Damage calculator

Estimate attack damage quickly using a classic StS-style teaching model (best for quick comparisons, not exact patch simulation).

Quick presets (click to load)

— Common early-attack feel check.
— How much raw scaling matters.
— When buffs and debuffs overlap.

Disclaimer: This uses a classic StS-style teaching model, not a guaranteed match for Slay the Spire 2 or current patches. Powers, relics, and keyword changes can alter real damage — verify in-game.

Formula (this page)

Start with base + strength (one strength = +1 to attack damage in many cases).
If target is vulnerable, multiply by 1.5 (unrounded; then we floor at the end).
If you are weak, multiply outgoing attack damage by 0.75 (common rounding pattern; games may differ).
Final: floor((base + strength) × vulnMult × weakMult).

Base card damage

Strength (each +1 to attack damage in classic model)

Target vulnerable (+50% taken → ×1.5 on this attack)

You are weak (outgoing attack ×0.75 in this model)

≈ 9 damage

How to use the result

Use it to compare lines (e.g. play order, whether a debuff is worth applying first).
If a relic/power changes rounding or multipliers, treat this as a baseline and verify in-game.
Link your deck idea with the Deck tool to share a quick plan with friends.

Long sessions? Consider a comfortable mouse for repeated clicks. Gear picks (affiliate) · Card list