About StatPlay

StatPlay is a free collection of 60 sports and fitness calculators built for lifters, runners, bettors-free stat heads and fantasy players. The site exists for one reason: sports math should be instant, transparent and free.

What we make

Our tools cover four areas. Fitness — one-rep max, BMI, body fat, BMR, TDEE, running pace, heart-rate zones, VO2 max and FFMI. Pro sports — NFL passer rating and win pace, NBA true shooting and usage rate, MLB ERA, WHIP and OPS, NHL save percentage and GAA. Season math — Pythagorean win expectations and magic numbers for all four leagues. Fantasy — points calculators for every league, trade evaluators, FAAB bidding, DFS value and standings.

How the formulas work

Every calculator shows the formula it uses and cites the standard source — the NFL's own passer-rating formula, Mifflin-St Jeor for BMR, the Riegel race-time model, Basketball-Reference's Pythagorean exponent for each league, and official scoring for DraftKings, FanDuel and season-long fantasy. Where a metric such as WAR or PER needs league-context data that a browser cannot know, we label the result clearly as an estimate and explain the simplification.

Privacy first

Everything runs locally in your browser. Your numbers are never uploaded, stored or shared — there is no backend to send them to. See our Privacy Policy for details on cookies and advertising.

Frequently Asked Questions