This is a problem I have had many times.
When I am planning battles the biggest problem for me is how large to make the battlefield.
I can't find any references online.
Is there a formula or ratio to help me?
(Also feel free to edit the tag list as I have no idea which to use.)

  • $\begingroup$ What era? (1,000 hoplites or Roman soldiers are packed a lot closer together than 1,000 soldiers on a modern battlefield.) $\endgroup$ – RonJohn Feb 23 '18 at 12:14
  • $\begingroup$ @RonJohn i think the closest era would be medieval. its fantasy so your typical "bunch of people with swords trying to hack each other to death" sort of fight. $\endgroup$ – Ajnatorix Zersolar Feb 23 '18 at 12:16
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    $\begingroup$ Do you have a specific example from your work? This depends on sooo many things I had to use more than one "o" in the word "so" $\endgroup$ – Raditz_35 Feb 23 '18 at 12:26
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    $\begingroup$ @ajnatorixzersolar Do you have any more information? Do you want to know how to make up a realistic medieval battle? If so, what are the circumstances? Btw edit your original post instead of giving information in the comments $\endgroup$ – Raditz_35 Feb 23 '18 at 12:50
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    $\begingroup$ In the real world battlefields aren't planned they are selected. Both sides are balancing a large number of factors while trying to ensure that all engagements are favorable to their side. As written this question is extremely broad. $\endgroup$ – sphennings Feb 23 '18 at 13:09

It depends how many troops are fighting, what type they are, and what techniques they're using. If you work out the rough area your armies take up (give each person 1msq for simplicity) you can split that into appropriate battalions and work out the scale required. I'd recommend drawing it out on a grid based system, then massaging it into reality.

In terms of formula, I think that's not necessary, if you draw out your armies you should be able to get a feel for how far apart they should be. Calculate - or decide - the range of any archers/magic, and have at least that gap between the sides before they commit to the battle, and work from there.


Steal from history.

Think about the technology of the period you are emulating. Then find a battle that actually happened that is like the battle you want. In that history battle, how many combatants were there and how big was the battle field?


Battle of Agincourt between Medieval English and French - about 1000 yards and 30,000 combatants.

Battle of Marathon between the ancient Greek and Persians - about 2 square miles and 100-200,000 combatants.

The Battle of the Somme in world war 1 occurred over about 20 square miles and ultimately involved at least 2 million combatants.

A battle like the Somme that takes months will probably sprawl over more territory than something like Waterloo that was wrapped up expeditiously. But you will not have to make anything up. You can even lift the terrain of the actual battlefield right into your story.


I would use https://www.daftlogic.com/projects-google-maps-area-calculator-tool.htm and real battles to estimate.
For example Grunwald battle. Wiki says it was the biggest battle in medieval times (I doubt that) and it was fought on a field of 3.02 square miles

But the formula to calculate could be easily formed. For cavalry, you have a size of one horse rump. Usually, cavalry are organized by regiment. So with a given formation, you can calculate the width of it. Same with infantry. For example, Spanish Tercio was made of 3000 men divided into 10 divisions. Tercio as a hollow square that gives you 750 men on each side. Usually, 5 rows of them give you a width of 150 men. So 150 meters.

So based on your choice of army you can calculate space they would take. On the other hand, remember that sometimes generals choose to fight not on flat plains but among trees that required a wider spread of formation.


There are many variables however you can make it as small or large as you want.

Depending on what type of battle it is it can vary from 1-2 thousand square meter to vast fields of 1-2 hundred thousand! Sites for battles aren't chosen by the size alone!

If it's an ambush against a larger army then a smaller site is better! So their numbers have less impact!

Two armies facing each other need more space. Here are some rough numbers per unit, at the beginning of the battle( because troop tactics can vary), as I see them!

Spearman and swordsman need less space say maximum 1 sq m. Because they are packed together.

Archers need at least twice that in order to draw their bow (2 sq m).

Cavalry I would guess needs 4-6 sq m, in order to maneuver their horses.

So a army composed of 400 spearmen, 100 infantry, 200 archers, 250 cavalry would need around 2400 sq m for the starting position alone. when you take battle tactics in then it is going to be a lot more.

Will they just charge at each other or will they maneuver in order to obtain a better position?

And this is not even what I thing is the most important part. Geography of the region should always be taken into consideration! I am unsure how much that matters in this case!

In conclusion the large the better....in general!


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