I need damage math mid-fight
Open the soul calculator, enter resources, and check lethal before you commit the turn.
Soul calculator →sts2calc.com · Independent tools
Slay the Spire 2 calculators
for decisions that matter
Wiki sites help you look things up. STS2Calc helps you run the numbers — lethal windows, draw odds, forge investments, and co-op roles. Built for Early Access climbers who want less guesswork mid-run.
Positioning: Tools > database dump. We link to character/card reference pages, but the product is calculators.
Calculators
Tools that map to player intent
Is this lethal?
Necrobinder Soul Calculator
Estimate single-card soul and doom damage for fast combat checks.
Will I see my key card?Draw Probability
Hypergeometric odds for opening hands and next-turn draws.
Forge now or later?Regent Forge Estimator
Compare simplified forge and star power scaling scenarios.
Who should I queue with?Co-op Synergy Checker
Check curated two-character pairings and team-role coverage.
Jobs to be done
What do you need right now?
I am thinning my deck
Compare draw odds before and after removals so you know if the win-con is real.
Draw odds →I am on my first climbs
Read the first-run guide, then use tools only when the decision is actually numeric.
First-run guide →Why sts2calc.com exists
Sites like full STS2 wikis are excellent for browsing cards, relics, and character pages. Many players still bounce when the real question is numerical: draw probability, soul scaling, or forge EV. STS2Calc focuses on those moments — interactive tools first, short strategy notes second, reference lists third.
Start with the first-run guide, skim mechanics, then keep calculators open while you climb. For roster browsing, use characters and cards. Official purchases stay on Steam.
STS2Calc is an independent fan-made tools site and is not affiliated with Mega Crit or the official Slay the Spire 2 wiki. Game systems may change in Early Access.