Gaming / Strategy and uncertainty
A 60% chance to hit is not a promise
Read Wesnoth’s combat numbers with a simple probability example—and see what an average leaves out.
In The Battle for Wesnoth, an attack’s numbers describe damage per successful hit and the number of strikes. The official 1.18 manual also distinguishes terrain defence—the chance not to be hit—from damage. A displayed probability describes uncertainty; it does not promise a fixed number of successes. This guide is based on documentation and arithmetic, not a claimed gameplay test. Read section 2.5 of the official manual.
What three chances really mean
Consider a deliberately simplified example: three strikes, each with an independent 60% chance to hit. Assume that all three strikes happen and that the probability does not change. A miss has probability 40%, so three misses have probability 0.4 × 0.4 × 0.4 = 0.064, or 6.4%.
That is not the same as saying a 60% attack “should always hit at least once.” The chance of at least one hit in this example is 93.6%. The remaining 6.4% is a real part of the model, even if it is the outcome a player least wants.
| Hits | Probability | Raw damage at 6 per hit |
|---|---|---|
| 0 | 6.4% | 0 |
| 1 | 28.8% | 6 |
| 2 | 43.2% | 12 |
| 3 | 21.6% | 18 |
For exactly one hit, there are three possible orders: hit–miss–miss, miss–hit–miss and miss–miss–hit. Each has probability 0.6 × 0.4 × 0.4. Adding them gives 28.8%. The same reasoning gives the other rows; together they total 100%.
Why average damage is not a result
If each successful strike causes six points of raw damage, the expected damage is 3 × 0.6 × 6 = 10.8. But none of the four possible outcomes in the table is 10.8. An expected value averages over possible outcomes; it is not a damage amount the attack must deliver.
This distinction gives a useful way to compare decisions. An average can help describe an option, while the low-end outcomes show what happens if it goes badly. If your plan fails after zero or one hit, the relevant probability in this example is 6.4% + 28.8% = 35.2%, not just the 60% printed beside an individual strike.
Return to the actual combat preview
Our table is not a replacement for Wesnoth’s combat calculation. It leaves out damage modifiers, units dying before all strikes happen and scenario-specific effects. The manual points players to the fight dialog’s Damage Calculations button for more information, including the chances that attacker and defender are killed. Check the actual encounter there. Consult the manual’s Fighting and Resistance sections.
The practical question is not simply “Which number is bigger?” Try asking “Which outcomes can this plan survive?” That is a decision aid from the example, not a claim that one universal strategy wins every battle.
Version and method
Scope: the project’s official 1.18-branch manual, read on 26 September 2026. Probabilities were calculated independently and checked in Python. No game installation, current-release compatibility test or hands-on review is claimed. Explore the Gaming reading path.