▸ The fitness math hub
Stop guessing.
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Eight precision-engineered calculators for the math behind cutting, bulking, hydration, and recovery. Built on peer-reviewed formulas. Zero signup.
Mifflin-St Jeor
BMR formula
Boer
LBM formula
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All calculators
Pick your number.
01
tdee
TDEE
Total Daily Energy Expenditure
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02
bulking
Bulking
Lean muscle gain calories
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03
cutting
Cutting
Fat loss deficit math
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04
lean body mass
Lean Body Mass
LBM via Boer formula
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05
intermittent fasting
Intermittent Fasting
Pick your fasting window
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06
water intake
Water Intake
Daily hydration target
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07
cycle
Cycle
Track your menstrual cycle
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08
reverse diet
Reverse Diet
Recover metabolism safely
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Real formulas.
Mifflin-St Jeor for BMR. Boer for LBM. Activity multipliers from peer-reviewed exercise physiology not random internet folklore.
Instant results.
Everything runs in your browser. No accounts. No tracking pixels selling your weight to advertisers. Just numbers.
Math you can verify.
Every calculator shows the formula and walks you through the inputs. Use it, learn it, never need us again.