It is a post apocalyptic world, all government systems have broken down, approx 95% of the worlds population is gone and the few survivors left are beginning to trade with each other. I need a currency, and I am thinking of giving every thing a calorie value. Eg. 500 calories = 1.2kg carrots = 200g beef steak = 3 cups of milk A day of hard labour would be worth 3000 calories (eg. 2kg beef steak and 6 cups of milk)

How do I value non-food items? I feel these are not as valuable as there is so much lying around (at the moment) - the valuable things are food and skills (eg daily labour).

What are the problems with this sort of currency?


  • $\begingroup$ Welcome to WorldBuilding! If you have a moment please take the tour and visit the help center to learn more about the site. Is your scenario in the near future so that we can just pretend that tomorrow most people are gone and everything else stays the same? Otherwise we would need more information about the differences between our current world and your scenario. For example: what differences are there in regards to resources because of the apocalypse? Was it a nuclear war, zombies, ... Have fun! $\endgroup$
    – Secespitus
    Commented Apr 29, 2017 at 22:06
  • 7
    $\begingroup$ Are you sure that you are not confusing currency and units of account? Currency must be by definition usable as a medium of exchange. I don't see how energy can be used as a medium of exchange -- even without an apocalypse we don't have particularly good ways of storing energy. $\endgroup$
    – AlexP
    Commented Apr 29, 2017 at 22:33
  • 3
    $\begingroup$ Stuff is only worth what people will pay for it. And the stuff you pay with in only worth what people will give you for it. $\endgroup$
    – Hot Licks
    Commented Apr 30, 2017 at 2:07
  • 2
    $\begingroup$ in a free market, price is dictated by supply and demand rather than merely by intrinsic value. Some people may want to do a little extra work to get eggs or a specific cut of beef, or some tasty fruits - which is exactly what is happening right now. $\endgroup$
    – njzk2
    Commented Apr 30, 2017 at 4:19
  • 2
    $\begingroup$ This is why I love WorldBuilding... I was about to ask almost this exact question, and these answers are extremely helpful. So let me just add my thanks to everyone who answered. $\endgroup$
    – MadPink
    Commented May 3, 2017 at 15:57

11 Answers 11


There's a few tweaks that your society would make rather rapidly. First and foremost, they would choose to standardize on a long-lasting caloric source like grains. If I already have dinner tonight, and you offer me 2 steaks in exchange for my work, I'm going to say no. Why? I don't need steaks and they spoil. Spoiled food is wasted wages. If you offer me two steaks, I'm going to try to trade them in for a grain as soon as possible. Grain is an excellent store of calories in the long term. Do this for a few days, and your employer will quickly realize that they can cut the middle man out and pay you in grain directly! I'd say it'd take about 5 days for this transition to occur!

This transition will also save you from the other issue: scurvy. Well, scurvy and dozens of similar diseases brought on by malnutrition. We need a lot more than just calories to survive. Spinach has a mighty 79 calories per bunch, contrasted with potatoes which come in around 160 calories per potato. It's a lot easier to grow a potato than a bunch of spinach, so farmers will quickly start growing only potatoes. However, spinach has loads of nutrients you need that aren't in potatoes. Your entire post-apocalyptic society could starve while being well fed on potatoes!

If you have standardized on grain, rather than calories, the value of spinach is going to be much higher than its mere caloric value suggests. You have to get away from measuring worth in calories before anyone will grow spinach. If the standard is calories of grain, rather than calories in general, there's room for the value of spinach to grow beyond the value of its calories.

Speaking of which, another reality is that your system will result in 0 meat. No steaks. Why? Because their value in calories is far far below the value in calories you had to put into the animal. In most cases it's at least a 10 fold difference in calories going into the animal to meat harvested, and its typically higher. Anyone trying to feed cattle would quickly realize that they're driving themselves bankrupt with such an inefficient industry. There's a reason why, when you go to the store, a 200g steak costs quite a lot more than 3 cups of milk!

This also avoids the reality that caloric content is remarkably hard to measure short of burning the food to see what it had in it. Caloric references like we have today are really just intended to be a reference point. Your actual caloric intake may be markedly different depending on many factors.

Edit: To respond to several comments, I'm not advocating a purely vegetarian diet, especially not one consisting just of potatoes and spinach. I'm merely pointing out that the caloric value of these foods is not their only source of value, and if the prices were fixed according to their caloric value, many source of food would simply not be used. Instead, I would expect the currency to transfer from calories to some other unit of value which is more capable of expressing the value of different food products.

  • 5
    $\begingroup$ Anyone trying to feed cattle would quickly realize Factory farming feeds grain to cattle, but I think that in a less industrial society cows might subsist on grass and hay. $\endgroup$
    – ChrisW
    Commented Apr 30, 2017 at 3:42
  • 2
    $\begingroup$ Plants alone do not provide enough nutrition for humans. A mix of plat and animal nutrition is the easiest way, especially in these scenarios. Depending on the apocalypse, hunting might become very viable. Eggs would still be viable anyways (some grains aren't well suited for human consumption). Honey would also be very valuable, and bees enhance certain crops. $\endgroup$
    – jaxad0127
    Commented Apr 30, 2017 at 4:06
  • 1
    $\begingroup$ This answer formulates well what can be answered to almost any question about how to get rid of money in a future society: if you remove, limit, or regulate money too much, people will re-invent money in some other way, so you can't get rid of it: people will find a substitute and money will exist again. Whether it will be precious metals, bottle caps or cigarettes, money will always be part of human society in some form or other. $\endgroup$
    – vsz
    Commented Apr 30, 2017 at 11:04
  • 1
    $\begingroup$ This answer demonstrates a fundamental lack of nutritional knowledge. People cannot live without protein and fat, just vegetables won't cut it even if micronutrients are taken care of. That's why people eat steak (or for example eggs/milk if vegetarian or soybeans in large quantities and avocado if vegan). All in all, it's not really an answer to the question but rather a plug for going vegetarian. $\endgroup$ Commented May 2, 2017 at 6:41
  • 2
    $\begingroup$ @SebastiaanvandenBroek I picked a single example of why calories would not be enough. Going further to describing the entirety of what a human body needs to function would have been overkill, since my next point was that we would still pick a currency, grains being a choice that's similar enough to calories for the OP. I do not advocate a spinach and potato diet =) $\endgroup$
    – Cort Ammon
    Commented May 2, 2017 at 14:46

A wage system requires a functioning market. If 95% of the population was wiped away, it is quite likely that you won't have a functioning market. People will work for food, and this is going to be far from standardised. It also means that there is going to be no market for much things besides food and shelter (as implied, btw, in your hypothetical example of 1 work day = 2 steaks + six glasses of milk): you are going to eat your salary, which means no provision for buying cell phones / automobiles / wheelbarrows / knives / clothes.

We are talking of a population similar to that of 500 AD. At such level of social decay, any currency, or "currency", will be local, not global or even "national" in the sense we understand "nations" today. And quite probably the whole economy will be replaced by a land-based system of production: if anyone can retain legitimate "property" of a stretch of land, they won't pay salaries for workers: they will allow workers to use the land for subsistence, and collect whatever surpasses subsistence levels as rent. Think feudalism or similar forms of landlordism. Excedents will be low, industry impossible, artisanship quite limited, commerce quite rare and mostly in the form of barter.


Food isn't currency, unless it keeps nearly forever and generally won't be used as food at that point. Food is a TRADE item.

Here is a lovely link to a story listing many food items used as currency.

As you can see, they have something in common. They don't spoil.

You asked for flaws in your system, here's a list.

  • Food is only valuable if you are hungry or you don't have any food.
  • If food spoils and you don't get to eat it, food LOSES value, it does not retain it.
  • You're talking caloric value in an APOCALYPSE? In order to measure that, the process involves burning the food in a controlled environment. For a regular person, there is not actually a way to measure that accurately. Sure, it's on the back of food, but that's for a limited time only.
  • There's way more to nutrition than calories. We need all kinds of stuff to survive. See Cort Ammon's answer here for more detail.
  • I see that you're talking early apocalypse here, because you're talking about other stuff not being as valuable because it's "lying around." It is counterintuitive to think that there's been time to set up an intricate calorie economy, but not enough time for people to grab everything they could get their hands on. Stuff like that has to be enforced, which means a government.

Requirements for currency.

  • There's a finite amount at any given time. There isn't too much or too little of it.
  • It doesn't rot or wear out. Best if it CAN get wet without being destroyed.
  • Portable, lightweight.
  • Difficult to cheapen, thin, or counterfeit.
  • Possibly fungible. That is, the value of the currency does not depend on weight or measurement. You might have different denominations or sizes, but they tend to be static enough that they don't have to be measured to know the value. Not true in the case of salt or tea, but as it was used more often, things like that would be compressed into bricks that are of uniform size and shape so that one doesn't have to have equipment to know the value of the money.

Resources you might want to look to:

Two Years Before the Mast is a great book, but the feature you do want to look at is what the currency in it actually was. Before California was adequately settled, they used hides as currency. Through out history, the pelts of animals, be they snake, squirrel, cattle, whatever, have been used as currency in places with either low cash or none at all.

Look at Cowrie shells.

Blankets, because they take time and resources to make.

Actual livestock.

Weapons. Specifically, knives because of portability.

In Fallout, it's bottle caps. They are everywhere, but, they are in limited quantity. Any object that fits the criteria can be your currency.NOTE: Don't ever use Fallout as you model for "stuff laying around" 200-300 years later, because most of that stuff and the skeletons supposedly lying around exposed, outdoors since the blast, actually would be disintegrated. Highly recommend the series "Life After People" if you want to see how quickly stuff breaks down.

  • $\begingroup$ Food is only valuable if you are hungry or you don't have any food. So is money, if you already have it you don't need it. Items which spoil easily would be localized to the areas with high demand. Assuming that this apocalypse did not destroy technology, we can measure the calorie content. Its like traveling in space. $\endgroup$ Commented Apr 30, 2017 at 2:29
  • 1
    $\begingroup$ @11thdimension Money is still valuable even if I have some. Even if I don't need money, having more for a time when I've spent what I already have is valuable. However, if someone tries to pay me in food that will spoil and I already have food that will spoil if I don't eat it, it doesn't have any value because I am not hungry, unless I can IMMEDIATELY find someone who is. $\endgroup$ Commented Apr 30, 2017 at 4:27
  • $\begingroup$ @11thdimension While technology might not be destroyed, do you currently have any method of measuring calories in your kitchen? This measurement does involve actually destroying the food by burning it. The poster says nothing about the tech level, so I am assuming our world. No idea if there's electricity. Food that spoils would not go to areas with high demand. It would be everywhere, if they are growing fresh produce. Non-perishable food is possible, but takes A LOT of work--like the process to dry rice... $\endgroup$ Commented Apr 30, 2017 at 4:36
  • 1
    $\begingroup$ I'd add to your list "fungible" (in that one item has equal value to another item). So random lumps of gold are not fungible because my lump is a different weight to your lump, but if you mint the gold into standardized coins then the coins are fungible. $\endgroup$ Commented Apr 30, 2017 at 9:54
  • 1
    $\begingroup$ @11thdimension Poster says: "all government systems have broken down, approx 95% of the worlds population is gone" with these figures it's almost impossible that a system like the one outlined has spread uniformly. There's no one to run power, any systems on anything but a local level. And again, food is a trade good unless it exhibits the characteristics of currency. $\endgroup$ Commented May 1, 2017 at 19:34

The only problem I could see with your calorie system, is that you're implementing it in a post apocalyptic world...

Basically I can picture people squabbling over the true vale of their foodstuffs and it's also easy to guess that in a post apocalyptic world where food and resources may be scarce that people would be inclined to barter and haggle based on perceived need. People who are starving are likely going to be willing to pay a little extra, call it gouging, but it's an unfortunate reallity.

Without a governing body, or people who are really inclined to work cooperatively, establishing standard values for goods is going to be really difficult.


Medieval Japan used the system you are looking for. The currency unit was the "koku" defined as:

"The standard unit of measure was the koku, the amount of rice needed to feed one person for one year."


There were also gold coins used for more valuable items (properties/animals/weapons/luxury items etc...) by the feudal elite. Paying everyting in rice bags was too impractical for high value items.

The value of a gold coin was initially set to 1 koku but as time passed and lords debased their currency, the value changed. Later, silver and brass coins were introduced as trade flourished and commoners used them too.

The common currency should be something that has intrinsec value,can be consumed even if there is no one to trade it with and doesn't decay with time (rice/grains). For more valuable transaction you want something Rare that cannot be duplicated or counterfeit easily (rare metal/minreal).

I can imagine the same system emerging in a post apocalyptic world. Food,bullets,tabacoo could be used as a commoners currency and some rare metal/mineral could be used for bigger transactions.

  • 1
    $\begingroup$ If we apply this logic to today, 1 koku would be the equivalent of about 150kg of rice which is about 750$. A small lord would earn about 1000 kokus in tax per year (750,000$). Medium lords would earn about 10,000 kokus per year (7,500,000$) and the most powerful lord in japan earned about 1,025,000 kokus (768 MMUSD). He was a billionaire! $\endgroup$
    – Fred
    Commented May 1, 2017 at 2:21
  • 1
    $\begingroup$ I really like that answer because most of answers above this one were saying more or less: "Well, that idea is stupid". And you just showed historical example that it might actually work. $\endgroup$
    – running.t
    Commented Jun 14, 2017 at 13:40

The word "salary" (wage) comes from salt in latin. This is because some societies paid their workers in salt. Salt is an important commodity to make another very important food : salty meat. Lacking refrigeration infrastructure meant that the only long term way to store meat (meat quickly spoils) is to salt it (there are other more complex ways like smoking it). Meat is a basic need due to the protein uptake needed too sustain human life (our brains and muscles demand a lot of protein to repair and keep alive). So, in a post apocalyptic world, salt might very well become an important commodity (or salted meat) and a reference of price. The only drawback is that the ancients did not produce salt from seawater due to lack of knowledge, but we nowadays can produce it (unless too far from sea) from sea water, wich is something way cheaper than the salt used in the past that came from mining operations.

tl;dr Use salt in areas far away from sea.


At first, non-perishable calories are probably the only thing starving people will trade for, but that won't last long, once people have a surplus to trade. I suspect that the initial unit would work out to one adult meal (or perhaps a day's food, instead?)

Dry rice, corn or especially beans (for the extra protein), since those can be eaten without being finely milled. Most people won't have access to a working mill, and unmilled wheat is not easy to digest!

I expect that the relative value of other items would vary by circumstances.

But dry grain or beans have a problem, they're not very value dense, relative to what an adult can carry. How many day's food could you carry, of dry corn and beans? (Milled flour is even worse, since it's bulky as well.)

But if you want to carry or trade more stored value than a week or two's calories (and still be able to eat), you'd want to hold your tradable-value in something more value per unit mass, some agreed-value, hard-to-forge tokens, like coins. In my post-apocalypse world, one group overstrikes certain coins, issuing them for local trade. Since they have about the only tools for that, it's a workable solution, at least short term.


Your currency is your trade items and supply and demand. Using a food as currency in such a World will lead to strife very quickly. Trying to store any large amount without protection is going to lead to strife. Control of the sources of this will lead to strife.

You hold what you can protect, if you hold too much someone else will want to take it from you and everyone is a bit nuts and probably heavily armed after going through an apocalypse.

Swapping resources between primitives was accomplished a few ways. Following is three commonish ones.

GIFTS:- a group would go (in numbers) singing (so the others know they have no bad intentions trying to conceal themselves. And gift the other group a bunch of resources they took with them, everyone has a meal meets some new ladies and leaves. Then in time the other group amasses some surplus and reciprocates.

TRADERS:- travel around swapping resources for other resources and taking them to places which are short on a particular resource. This is driven by supply and demand basically. The traders could be group sanctioned or group owned instead just trading within certain groups where they have treaties of some kind.

RAIDING:- a belligerent group attacks another and takes what it wants if it can get away with it.

TRIBUTE:- a group basically taxes others around it, either because it is the most powerful or because it has some other advantage such as bloodline. This is very common both large scale and small within groups themselves. The tribute comes in the form of freely given gifts in outward appearance, but it's really essentially tribute in that there will be repercussions if they stop freely giving these gifts out of the kindness of their hearts..

Between nominally friendly groups the first is best, and it was used even during wars in some places. It's drawback is it's basically a trust relationship, although there is much more involved including gene flow than just the exchange of resources. It's a very important way of exchanging ideas, stories and other things as well. In theory these are called gifts, but they're actually well thought out and calculated. The reciprical gits need to match or better the original or there will be some nasty gossip. Nasty gossip in primitive societies can quickly lead in nasty directions.

Anything along the lines of universal wages or currency needs an organised society to protect/enforce it. So the Japanese used units of rice as a measure of wealth, but they could only do so because they were highly structured and strong. In times of trouble this fell to bits just as currencies do today.

  • $\begingroup$ "singing, so the others know they have no bad intentions" They did that in a musical about the French, ironically singing "Do you hear the people sing?" before letting them eat cake. ;) $\endgroup$
    – Loduwijk
    Commented May 3, 2017 at 15:08

Depending on the type of post-apocalypse you're working with, an unexpectedly great need may stem from consumables that can no longer be produced due to the waning of industry. In a simple example that always comes up: Ammo.

There is a limited and always dwindling supply of it. Therefore, its value will continuously go up with only minor bumps in the opposite direction as new caches are discovered.

Turning it on its head, your reality could function in this way on a variation of the gold standard: Any small portable object that can no longer be produced but is never consumed, and exists in relatively large quantities.

An example of such a currency is the bottlecaps in the Fallout universe, which are accepted for exactly the reasons above.

  • $\begingroup$ The downside to ammunition as a currency is that ammunition has a shelf time. So, after max. two generations, your currency is worthless and may in part be dangerous to the owner. While bullets might be a valuable commodity, i doubt their general usefulness as a currency. $\endgroup$
    – Burki
    Commented May 3, 2017 at 12:31
  • $\begingroup$ @Burki My first part was mostly there to counter the "food is the only thing that matters!" argument. The second part is what really counts. $\endgroup$
    – Weckar E.
    Commented May 3, 2017 at 12:42
  • $\begingroup$ @Burki So the story unfolds during those two generations; problem solved - for the author, at least, though not for the general case. Still, I have seen people shoot ammo that is approximately 100 years old. Some people found boxes of 40-50 year old ammo and made youtube videos about shooting it, showing it was still good; after that a bunch of similar accounts came up with people trying to find the oldest ammo they could among grandpa's old stuff. Some people found 90+ year old ammo and shot it with few problems. It just needs to be stored well. We do not know the age limit of modern ammo. $\endgroup$
    – Loduwijk
    Commented May 3, 2017 at 15:15
  • $\begingroup$ @WeckarE. In some areas, there are reasonable amount of people to make their own ammo. I knew a guy (deceased now) who stored raw lead and brass in his basement and made his own ammo. I don't know if he ever made his own propellant; probably not, but it would not surprise me if he did that too since he was that kind of guy. These kind of people would cause the situation you describe to level out eventually, though it would be very scarce for sure, and the value would be very high at that point. $\endgroup$
    – Loduwijk
    Commented May 3, 2017 at 15:20
  • 1
    $\begingroup$ @WeckarE. I don't think I understood it. What you said is fairly straightforward. I was just adding more information. Concerning your ammo example, you stated that occasional caches would be found which would introduce more quantity. I agree. I was merely stating that there would also be a small but steady input from ammo-reloaders. This input would likely be smaller than the output, but it would cause the numbers to stabilize eventually, even if the stable point is a very low number. If you think we are misunderstanding, point out where, or clarify. I don't think this is a bad answer at all. $\endgroup$
    – Loduwijk
    Commented May 5, 2017 at 17:39

A currency has to be limited in amount available (like gold, which is rare, or bottlecaps, which are not made anymore). Any grain would instantly crash the market because you can plant it and produce more of it. Some rare sort of ammunition (like incendiary 7.62 Warsaw Pact rounds) would be more reasonable. As a general rule, however, consumables aren't good currency.

  • 1
    $\begingroup$ Welcome to WorldBuilding! Interesting answer. Reminds me of the Metro Series. If you have a moment please take the tour and visit the help center to learn more about the site. Have fun! $\endgroup$
    – Secespitus
    Commented May 2, 2017 at 17:42

I think it depends on how seriously you're taking your universe - with a "campy" universe you can take liberties with realism and the holes that can be poked in it are fun. With a very serious universe those kinds of liberties are problematic and immersion-breaking.

The caloric currency concept makes it sound like you're going for seriousness, in which case (for reasons stated by others) caloric currency has too many holes in it to work.

By just replacing "currency" with "trade" you solve a lot of your problem. You wouldn't need to worry about precise measurements on foodstuffs, because it's not currency - it's trade. One guy might be able to trade a handful of bullets for a steak, but another guy might need to sweeten the pot. Trade isn't as rigid and leaves room for interpretation, haggling, unfairness, etc.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .