Most generic answers to “how many calories should I eat to lose weight” land somewhere around 1,200, 1,500, or 2,000 — numbers pulled from population averages rather than anything specific to you. The actual answer depends on your body size, age, sex, and activity level, and it’s genuinely calculable with a formula that takes just a few minutes to work through.
This guide walks through exactly how to find your own number, step by step, using the same method registered dietitians and sports scientists commonly use as a starting point.
The Two Numbers You Need First
Before getting to a weight-loss target, you need two intermediate numbers:
BMR (Basal Metabolic Rate): the calories your body burns just existing — breathing, circulating blood, maintaining organ function — if you stayed in bed all day.
TDEE (Total Daily Energy Expenditure): your BMR plus the calories burned through daily movement, exercise, and digestion. This is your actual maintenance number — what it takes to keep your current weight stable.
Weight loss happens by eating somewhat below your TDEE, not your BMR. Confusing the two is one of the most common reasons generic calorie targets end up too aggressive or too lenient for a given person.
Calculate Your BMR
The most widely used formula for this is the Mifflin-St Jeor equation, generally considered one of the more accurate options available without specialized lab equipment:
For men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + 5
For women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) − 161
If you’re working in pounds and inches instead of kilograms and centimeters:
For men: BMR = (4.536 × weight in lbs) + (15.88 × height in inches) − (5 × age) + 5
For women: BMR = (4.536 × weight in lbs) + (15.88 × height in inches) − (5 × age) − 161
Worked example: a 36-year-old woman who is 5’6″ (167.6 cm) and 160 lbs (72.6 kg): BMR = (10 × 72.6) + (6.25 × 167.6) − (5 × 36) − 161 = 726 + 1,047.5 − 180 − 161 ≈ 1,432 calories
That’s her estimated calorie need at complete rest — not her actual daily target.
Adjust for Activity Level to Find Your TDEE
Multiply your BMR by an activity factor that reflects your typical week, not just structured workouts:
| Activity Level | Description | Multiplier |
|---|---|---|
| Sedentary | Little to no exercise, desk job | 1.2 |
| Lightly active | Light exercise 1–3 days/week | 1.375 |
| Moderately active | Moderate exercise 3–5 days/week | 1.55 |
| Very active | Hard exercise 6–7 days/week | 1.725 |
| Extremely active | Physically demanding job or 2x/day training | 1.9 |
Continuing the example: if this woman is moderately active, her TDEE is: 1,432 × 1.55 ≈ 2,220 calories — this is roughly what it takes to maintain her current weight.
Apply a Moderate Deficit
A commonly cited, sustainable deficit is 300–500 calories below TDEE, generally corresponding to about 0.5–1 pound of fat loss per week, based on the widely used approximation that one pound of body fat represents roughly 3,500 calories.
Continuing the example: a 500-calorie deficit would put her weight loss target at: 2,220 − 500 ≈ 1,720 calories per day
Notice how different this is from a generic “1,500 calorie” recommendation — in this case, that generic number would have created a much larger deficit than intended for her specific stats and activity level.
Why This Beats a Flat, Generic Number
Two people can have the exact same generic “recommended” calorie target and end up with completely different real-world deficits, because that target doesn’t account for their individual TDEE. A flat number might represent:
- A comfortable, sustainable deficit for one person
- A negligible deficit for someone with a lower TDEE
- An aggressive, uncomfortably large deficit for someone with a higher TDEE
Calculating your own BMR and TDEE closes that gap, turning a population-average guess into a number that’s actually built around your specific body and activity level.
Important Safety Guardrails
Don’t go below your BMR. Since BMR represents what your body needs at complete rest, eating consistently below it isn’t a “bigger” deficit in a helpful sense — it’s a signal that your intake isn’t meeting basic physiological needs, which is associated with fatigue, muscle loss, and metabolic slowdown over time.
There are commonly cited general floors, regardless of calculation. Widely referenced guidance suggests most adult women shouldn’t go below roughly 1,200 calories per day, and most adult men shouldn’t go below roughly 1,500 calories per day, without direct medical supervision — even if a formula technically suggests a lower deficit target.
These formulas are estimates, not exact measurements. Individual metabolic variation, genetics, and factors like muscle mass mean your real-world results may land 5–15% higher or lower than the calculated number. Treat your first result as a starting point to test, not a fixed prescription.
Recalculate periodically. As you lose weight, your BMR gradually decreases along with it, since a smaller body requires less energy to maintain. Recalculating every 10–15 pounds of change, or if progress stalls for 2–3 weeks despite consistency, keeps your target aligned with your current body rather than your starting point.
Signs Your Calculated Target Needs Adjusting
- Persistent, unusual fatigue beyond normal adjustment to a new eating pattern
- Stalled progress for several weeks despite consistent adherence, which may indicate your TDEE estimate needs revisiting as your body changes
- Intense, hard-to-manage hunger or cravings, which can indicate the deficit is too aggressive for sustainable adherence
- Losing weight unexpectedly fast (well beyond 1–2 pounds per week consistently), which may indicate the calculated deficit is larger than intended
Any of these are reasonable signals to revisit the calculation, adjust the activity multiplier, or consult a doctor or registered dietitian rather than pushing through discomfort.
Who Should Skip Self-Calculation and Talk to a Professional Instead
- Anyone with a current or past history of disordered eating, for whom calorie counting itself can be a difficult or risky approach
- Anyone with a diagnosed medical condition that affects metabolism or nutrition needs (thyroid conditions, diabetes, and others)
- Pregnant or breastfeeding individuals, whose calorie needs differ substantially from standard weight-loss formulas
- Anyone who has tried self-calculated targets and consistently experiences the warning signs listed above
Frequently Asked Questions
Is the Mifflin-St Jeor equation actually accurate?
It’s widely considered one of the more accurate available formulas without lab equipment, generally estimated to be accurate within about 10% for most people. It was developed using a specific population sample, so individual results — particularly for people outside that original population or with significantly different body compositions — may vary somewhat more than that.
How much should I cut my calories to lose 1 pound a week?
Roughly 500 calories below your calculated TDEE, based on the commonly used approximation that one pound of fat represents about 3,500 calories. This is a widely used estimate rather than an exact measurement, and real-world results can vary.
Why did my weight loss stall even though I’m eating my calculated number?
This is common as your body adapts and your BMR naturally decreases somewhat as you lose weight. Recalculating your BMR and TDEE based on your current weight, rather than your starting weight, often resolves this.
Should I eat back the calories I burn from exercise?
This depends on how you calculated your activity multiplier. If your multiplier already accounts for your typical exercise routine, you generally shouldn’t need to add calories back for regular workouts. If you calculated based on a sedentary multiplier and add in unusually intense or unplanned activity, some adjustment may be reasonable.
Is it dangerous to eat below my calculated BMR?
Consistently eating below BMR isn’t recommended without medical supervision, since it represents less energy than your body needs even at complete rest, which is associated with fatigue, muscle loss, and other negative effects over time.
Final Thoughts
Finding your actual calorie target for weight loss doesn’t need to rely on a generic number pulled from an article or app default. Calculating your BMR, adjusting for your real activity level to find your TDEE, and applying a moderate, sustainable deficit gives you a number that’s actually built around your body — one that’s far more likely to produce steady, sustainable results than a flat recommendation designed for an “average” person who may look nothing like you.
