Pokémon Damage Formula, Step by Step

Every damage number in Pokémon Champions ranked comes out of one formula, at level 50. Here it is in the order the game applies it — base damage, then spread, weather, crit, the 85–100 roll, STAB, type effectiveness and burn — the same math our damage calculator runs.

Open the Pokémon Champions damage calculator →Level 50 ranked defaults, all 16 rolls, exact OHKO / 2HKO chance. Free, in the browser.

Step 1: base damage

base = floor(floor(floor(2×Level / 5 + 2) × Power × Atk / Def) / 50) + 2

At level 50 (the ranked standard), 2×50/5 + 2 = 22, so base damage is roughly 22 × Power × Atk/Def / 50 + 2. The Atk/Def ratio is the heart of it: doubling your Attack or halving their Defense do the same thing.

Those Attack and Defense numbers are the stats after nature (+10% / −10%) and stat stages (−6 to +6). A critical hit later in the chain ignores the attacker’s negative stages and the defender’s positive ones.

Step 2: the modifier chain

Modifiers then apply in a fixed order (each rounding as it goes):

Spread — a move hitting two targets in doubles does ×0.75 to each.
Weather — e.g. rain: Water ×1.5, Fire ×0.5. Sun is the inverse (Fire ×1.5, Water ×0.5).
Critical hit — ×1.5, and it ignores the attacker's negative stages and the defender's positive ones.
Random roll — every hit rolls ×0.85 to ×1.00 (16 possible values; that's why results are a range).
STAB — ×1.5 when the move matches the user's type (×2 with Adaptability).
Type effectiveness — ×4 / ×2 / ×1 / ×½ / ×¼ / ×0 from the type chart.
Burn — physical moves from a burned attacker do half damage (Guts ignores this).
Everything else — items (Life Orb ×1.3), abilities (Multiscale, Tinted Lens), screens, Friend Guard… all as 4096-based multipliers.

That order is why two calcs that “look the same” can disagree by 1 HP: each step floors as it goes. Change any input in the calculator and the range updates from this chain, not from a shortcut.

Worked example

Level 50 attacker, 150 Attack, 100 Power STAB move into 100 Defense, neutral matchup, no items: base = floor(floor(22 × 100 × 150/100)/50) + 2 = 68. STAB makes it 102; the random roll spreads that to 87–102. Against a 175 HP target that's a 50–58% chunk — a clean 2HKO. Change any input in the calculator and watch which step moved the number.

Why calculators matter

The stacked floors (round-downs) make mental math unreliable — two builds that look identical on paper can differ by one HP at the roll, and that HP is the difference between a guaranteed KO and a 6.3% miss. Exact rolls are the whole game at high rating.

Champs Calc evaluates every one of the 16 possible damage rolls, shows the percentage of the defender’s HP, and reports the exact chance to OHKO or 2HKO. Ranked defaults to level 50; the spread-move reduction (×0.75) and doubles screens are built in.

Run this formula on a real matchup →Pick attacker, move and defender. Same modifier order as above.

Related mechanics

Type chart — the ×4 / ×2 / ×½ / ×0 step, including dual-type products and immunities.
Natures chart — which nature raises or lowers the Attack or Defense that goes into base damage.
Stat stages — the −6 to +6 multipliers on those stats, and what a crit ignores.

Damage calculator · Damage formula · Type chart · Natures · Stat stages

Fan-made reference. Not affiliated with Nintendo, Game Freak or The Pokémon Company.