Skirmforge: Combat Calculator

Every percentage opens up: see the target number, the formula and the intermediate values behind each hit chance and damage result.

Run the fight. Skirmforge does the maths.

Skirmforge combines a fast encounter tracker with a combat calculator that shows its work, and a tactical square grid that feeds the two together. Built for game masters of tabletop role-playing games compatible with 5th-edition rule sets. Fully offline, no account, no tracking.

EVERY NUMBER OPENS UP A percentage you cannot check is worth nothing at the table. Every result carries its steps with it — the target number, the formula, the intermediate values — so you can verify it, explain it to a player, or overrule it.

ENCOUNTER TRACKER • Roll initiative for one combatant or for everyone, ties broken by Dexterity • Round counter, highlighted active turn, and a step back when somebody was skipped • Hit points, temporary hit points and conditions with an automatic round countdown • Concentration flag with the suggested save DC already worked out

COMBAT CALCULATOR • Hit chance with advantage, disadvantage, a third die, and crit ranges of 20, 19–20 or 18–20 • Expected damage per round: crits double dice only, several attacks per turn, reroll options and once-per-turn bonus damage weighted correctly • Damage resolution with resistance, immunity, vulnerability, flat reduction and half-on-save • Rounds to kill, plus the probability of finishing within a given number of rounds • Comparison mode: two attack profiles side by side with the delta

TACTICAL GRID • Tokens are generated from your combatants and snap to the square as you drag • Movement is counted by the rules and checked against the speed; difficult terrain doubles a square • Measuring tool and range check: in range, long range with disadvantage, or out of range • Area templates — cone, sphere, line, cube — mark the affected squares and the affected tokens • Those tokens go straight into a multi-target damage calculation, each target with its own saving throw, resistances and half-on-save

DICE • Expression parser: 4d6kh3, 2d20kh1+5, 1d8+1d6+3, explode with !, reroll with r1 • Roll history per encounter with every individual die still visible

APPLE WATCH • The initiative list on your wrist, next turn by tap with a haptic tick • Hit points on the Digital Crown, and a quick roll with a live hit-chance readout • Complication showing the round and whose turn it is • Keeps working when the iPhone is out of reach

IPHONE AND IPAD A real split layout on iPad with the map in the detail column — not a scaled-up phone screen.

PRIVACY No account, no sign-in, no analytics, no advertising, and no network requests at all. Everything you enter stays in a local database on your own device.

FREE AND PRO Free gives you one saved encounter with up to six combatants, hit chance, basic expected damage, the grid with tokens, movement and measuring, the dice roller, and the complete Apple Watch app. The one-time Pro unlock lifts the limits and adds comparison mode, rounds to kill, the damage distribution chart, area templates with multi-target damage, difficult terrain, and the grid rule variants. One purchase, Family Sharing enabled, no subscription.

English and German throughout, with Dynamic Type, VoiceOver and Reduce Motion supported.

Skirmforge is an independent tool and is not affiliated with, endorsed by or sponsored by any game publisher. Sample creatures and condition names come from the System Reference Document 5.1. This work includes material from the System Reference Document 5.1, licensed under CC-BY-4.0.

Open it at the table and stop doing arithmetic in your head.