# Calorie Calculator

> calorie calculator that estimates daily calorie needs and macros from age, weight, and activity level using Mifflin-St Jeor. Free, runs locally, no signup.

- **Canonical URL:** https://boringtoolskit.com/calorie-calc/
- **Category:** Health
- **Evidence level:** authored-methodology
- **Reviewed:** July 26, 2026
- **Last verified:** 2026-10-12
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

## How it works

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

- 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.

## Common 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.

## Related tools

- /bmi-calc/
- /body-fat-calculator/
- /calculators/health/

## Sources

- [Mifflin-St Jeor resting metabolic rate equation](https://pubmed.ncbi.nlm.nih.gov/2305711/)
- [Body weight planner and nutrition resources](https://www.niddk.nih.gov/bwp)

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*Local planning estimate. Verify current terms, rates, and policies before acting.*