How is charge range calculated in most wargames?

A unit's charge range is its charge dice roll, usually 2D6, plus any flat bonuses, minus terrain penalties. The total is the maximum distance it can move into combat. This tool adds your bonus, subtracts penalties, and reports the full range of outcomes.

What is the probability of making a charge?

For a 2D6 charge you need the dice to roll at least the gap minus your bonus plus penalties. The tool computes the exact 2D6 distribution, so you can see, for instance, that a 9-inch charge succeeds about 28 percent of the time before bonuses.

What counts as a reliable charge?

A common rule of thumb is a charge you make 80 percent or more of the time, which on 2D6 means needing a 6 or less after bonuses. The tool flags whether your gap clears that threshold so you can decide whether to commit or reposition.

Does it handle 3D6 or single-dice charges?

Yes. Select the dice your game uses and the tool rebuilds the probability distribution accordingly, whether that is 2D6, 3D6 keep highest two, or a flat single die, so the odds match your ruleset.

How do terrain modifiers work?

Many games slow charges through difficult terrain. Enter the penalty in the same units as movement and the tool subtracts it from the charge total, lowering both the expected reach and the success probability for the gap.

What is the Wargame Charge Range & Reach Calculator?

Enter your unit's movement, charge dice, terrain modifiers, and a target gap to compute average, best-case, and worst-case charge range plus the probability of making a 2D6 charge over the distance. For Warhammer and similar tabletop wargamers. It runs free in your browser on Gera Tools, with nothing uploaded.

Wargame Charge Range & Reach Calculator

Name: Wargame Charge Range & Reach Calculator
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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Committing a charge in a tabletop wargame is a gamble on the dice, and knowing the odds before you declare it saves games. This calculator reports your unit’s average, best, and worst charge range and the exact probability of covering the gap to the enemy.

How it works

Charge range is the charge dice plus a flat bonus minus terrain penalties. For the default 2D6 charge:

needed roll = gap − bonus + penalty
P(success)  = P(2D6 ≥ needed roll)   from the exact 36-outcome distribution
average     = 7 + bonus − penalty    (2D6 averages 7)
best        = 12 + bonus − penalty
worst       = 2 + bonus − penalty

The 2D6 distribution is not flat — 7 is the most likely result and the tails are rare — so a one-inch change in the gap can swing the odds sharply. The tool builds the full distribution for 2D6 or 3D6 so the probability is exact, not a guess.

The full 2D6 probability table

Because the distribution is bell-shaped, the odds change dramatically at the margins:

Roll needed	P(2D6 ≥ roll)	Verdict
2	100%	Guaranteed
4	92%	Very safe
5	83%	Safe
6	72%	Comfortable
7	58%	Coin flip
8	42%	Risky
9	28%	Long shot
10	17%	Very unlikely
11	8%	Desperate
12	3%	Almost never

This is why a +1 charge bonus is often worth far more than it appears: it shifts every entry one row up. A unit needing a 9 with no bonus (28%) suddenly needs an 8 with a +1 bonus (42%), a meaningful difference when the game depends on contact.

Tips and worked example

A unit needing a 9-inch charge on 2D6 with no bonus succeeds only about 28 percent of the time, which is why a +1 or +2 charge ability is so valuable: a +2 bonus turns that into needing a 7, jumping success to roughly 58 percent. Treat anything you make less than about 60 percent of the time as a gamble, and use repositioning or charge-boosting abilities to pull risky charges down to a 6-or-less roll, which lands better than 70 percent of the time.

Consider difficult terrain carefully. A terrain penalty of 2 inches on a 7-inch gap is effectively the same problem as a 9-inch gap in the open — both need a 7 or better, with the same coin-flip odds. The calculator lets you model this directly so you can decide whether to wait for a cleaner line or commit now.