How to Find Your Maintenance Calories (TDEE) Without the Guesswork
Almost every nutrition goal — losing fat, gaining muscle, or just holding steady — starts from one number: your maintenance calories. Get this wrong and every diet built on top of it is guesswork. Get it roughly right and fat loss becomes arithmetic. Here's how to find yours without a lab.
What "maintenance calories" actually means
Your maintenance calories are the amount of energy you burn in a typical day. Eat that amount and your weight stays flat. Eat less and you lose; eat more and you gain. The technical name is TDEE — Total Daily Energy Expenditure — and it's the sum of a few things:
- BMR (basal metabolic rate): what your body burns just staying alive — breathing, pumping blood, keeping warm. This is the biggest chunk, usually 60–70%.
- Activity: everything you do on top of that — walking, training, fidgeting, standing.
- Digestion: a small tax your body pays to process food (protein costs the most to digest).
You don't need to measure each piece. You estimate BMR from a formula, then multiply by an activity factor.
Step 1: Estimate your BMR
The most widely used equation is Mifflin-St Jeor, because it's accurate for most people and only needs numbers you already know: weight, height, age and sex.
- Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(years) + 5
- Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age(years) − 161
Take a 30-year-old man, 85 kg, 180 cm: BMR = 850 + 1125 − 150 + 5 = 1,830 kcal. That's what he'd burn lying in bed all day.
Step 2: Multiply by your activity level
Nobody lies in bed all day, so you scale BMR up by how active you are. This is the step people get wrong — most overestimate. Be honest about a typical week, not your best one.
| Activity level | Looks like | Multiplier |
|---|---|---|
| Sedentary | Desk job, little exercise | 1.2 |
| Lightly active | Light exercise 1–3 days/week | 1.375 |
| Moderately active | Training 3–5 days/week | 1.55 |
| Very active | Hard training 6–7 days/week | 1.725 |
| Athlete | Physical job + daily training | 1.9 |
Our 85 kg man trains four times a week, so he's moderately active: 1,830 × 1.55 ≈ 2,835 kcal. That's his maintenance — the number every plan starts from.
Step 3: Treat it as a starting estimate, then verify
Here's the part most calculators skip: the formula gives you an educated guess, not a fact. Real metabolisms vary by a few hundred calories in either direction. The only way to know your true maintenance is to eat a consistent amount for two weeks and watch the scale trend.
- Weigh yourself most mornings and look at the weekly average, not any single day (water weight swings daily).
- If your average is flat over two weeks, you found maintenance.
- Drifting up? Your real maintenance is lower than the estimate. Drifting down? It's higher.
Adjust by 100–150 kcal and check again. Two or three of these cycles and you'll know your number better than any equation could tell you.
Why the number matters more than the diet
Once you know maintenance, everything downstream gets simple. Want to lose fat? Eat a few hundred below it. Building muscle? A bit above. No more "I don't know why I'm not losing weight" — you'll be able to see exactly where you are relative to your own baseline.
The catch is that it only works if you actually track what you eat with enough consistency to compare against the number. That's the whole point of a fast food log: it turns your maintenance estimate from trivia into a tool you use every day.
ForgeLift estimates your maintenance calories from your profile the moment you set it up, then lets you log food in seconds to stay on target — free and private on iPhone.