Calorie Calculator
Adjust the inputs below. Results update as you type.
How it works
A calorie target estimate combines resting energy needs with activity to suggest daily intake for maintenance, loss, or gain. Numbarn supports common equations (such as Mifflin–St Jeor or Harris–Benedict style workflows) and goal adjustments with safety-minded floors—useful for planning, not for medical treatment.
Enter age, sex, height, weight, and activity level, then choose a goal. Aggressive deficits can undermine adherence and nutrient intake; very high surpluses can outpace training recovery. Recalculate as weight and activity change rather than locking one number for months.
Pair calorie targets with protein, sleep, and strength or cardio context. Medications, medical conditions, and disordered-eating history require professional care—do not use a web calculator as a substitute. If weight is not moving after several weeks of honest tracking, adjust one variable at a time (intake, steps, or training) and reassess.
Input guidance
- Age, sex, height, and weight should be current and measured when possible.
- Pick the activity level that matches a typical week, not your best week.
- Choose a modest goal adjustment before aggressive deficits or surpluses.
The formula
Maintenance calories = BMR × activity factor (1.2 sedentary to 1.9 very active). For weight loss, subtract about 500/day to lose roughly 1 lb/week; add a surplus to gain.
Worked example
A BMR of 1,600 with a lightly active factor of 1.375 gives about 2,200 maintenance calories. A 500-calorie deficit (1,700/day) targets about 1 lb of loss per week.
More examples to test
- Maintenance calories at moderate activity, then a moderate deficit: compare weekly vs daily targets.
- Switch formula (Mifflin vs Harris-style) and note the spread before locking a target.
How to interpret results
Treat the output as a starting intake estimate. Adjust from trend weight and adherence over weeks, not day-to-day noise.
When this can be inaccurate
Equations estimate populations. Medical conditions, medications, and measurement error can shift true needs.
Change history
- July 2026: Goal workflow, formula choice, and safety floors documented.
- June 2026: Energy-estimate path quality-reviewed.
Site-wide corrections also appear on the corrections log.
Track calories and macros with a proven app
General wellness tracking resource.
Frequently asked questions
How many calories should I eat to lose weight?+
A deficit of about 500 calories below maintenance loses roughly a pound a week. Larger deficits work faster but are harder to sustain and can lose muscle.
Why a 3,500-calorie rule?+
A pound of fat stores roughly 3,500 calories, so a 500/day deficit (3,500/week) approximates one pound of loss — a useful estimate, not an exact law.
Are these numbers exact?+
No. They estimate from formulas and activity factors. Track your weight over a few weeks and adjust intake based on real results.
Can this calculator diagnose a condition?+
No. It is a screening and education tool only, not a clinical diagnosis.
When should I seek professional advice?+
Seek professional advice when results are extreme, persistent, or conflict with symptoms, goals, or prior medical guidance.
Guided next steps
Want the full workflow? Use this calculator inside a step-by-step guide.
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