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General estimate for planning only — not medical advice. Consult a doctor about your specific situation.
Calculation details
Energy-needs estimate only, not medical nutrition advice. Population equations and activity factors can differ from measured individual needs; discuss health decisions with a qualified clinician.
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What does this calculator estimate?
calorie calculator that estimates daily calorie needs and macros from age, weight, and activity level using Mifflin-St Jeor. Free, runs locally, no signup.
How this calculator works
Formula
Mifflin-St Jeor BMR: men 10x weight(kg) + 6.25x height(cm) - 5x age + 5; women subtract 161; multiply by the activity factor for maintenance calories.
Worked example
A 30-year-old, 170 lb (77.1 kg), 5 ft 9 in person at a 1.20x activity factor: BMR about 1,721 kcal/day, maintenance about 2,066 kcal/day.
Assumptions to verify
- Population equations cannot measure individual metabolism.
- Pregnancy, adolescence, medical conditions, medications, and training load can materially change energy needs.
- This is educational planning information, not medical nutrition advice.
- This tool provides general estimates for planning and education only; it is not medical advice and not a substitute for a qualified healthcare professional.
- Always consult your doctor or another healthcare provider about your specific situation.
Frequently asked questions
Should I eat exactly this number?
No. Treat it as a starting estimate and adjust based on real progress, hunger, training, and clinical guidance.
Does activity factor matter?
Yes. It is often the largest assumption and easy to overestimate.
Who should not rely on this alone?
People with medical conditions, pregnancy, eating-disorder risk, adolescence, or clinical nutrition needs should use qualified guidance.
Cite this tool
BoringToolsKit. “Calorie Calculator.” boringtoolskit.com/calorie-calc/. Free to reference in articles, syllabi, and answer posts with a link.
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