Your calorie calculator is probably wrong
Formulas like Mifflin-St Jeor guess from population averages and can miss by 200 to 600 calories a day. Adaptive TDEE works backwards from your own scale and food log instead.
The math is one line
If you ate 2,300 a day and lost half a pound a week, your body burned more than you ate. The gap is your real maintenance.
TDEE = average calories − (weekly weight change × 3,500 ÷ 7)3,500 cal is roughly 1 lb of body mass, or 7,700 cal per kg
- Average intake
- 2,300 cal / day
- Weight trend
- −0.5 lb / week
- Covered by body mass0.5 × 3,500 ÷ 7
- +250 cal / day
Your TDEE
2,550cal
Two habits and some patience
You supply the weight and the calories. The trend does the rest.
1
Weigh in every morning
Same conditions each day: after waking, before eating. Single readings bounce around. The trend is what counts.
2
Log what you eat
Total calories, as close as you can get. Being consistent matters more than being perfect.
3
Give it two to four weeks
Once there is enough data, the gap between what you ate and what the scale did is your burn rate.
What a formula cannot see
A formula estimates once. Adaptive TDEE keeps measuring.
Activity
Formula: One of five preset multipliers
Adaptive: What you actually burned, week by week
Metabolism
Formula: A population average for your size
Adaptive: Yours, including muscle mass and genetics
During a cut or bulk
Formula: Stays fixed until you redo it
Adaptive: Moves as your body changes
Pick how you track it
All three use the same math. They differ in how much of it you do by hand.
Calculator
Paste in a few weeks of weight and calories and get a number now. No sign-up.
Open the calculatorSpreadsheet
The classic nSuns sheet. Log by hand in Google Sheets or Excel and watch the number settle.
Zolt
Pulls your weight from Apple Health or Health Connect, reads your food log, and updates your target every day. Nothing to calculate.
Common questions
What is adaptive TDEE?
Adaptive TDEE (Total Daily Energy Expenditure) is a personalized method of calculating your maintenance calories using your actual weight changes and food intake over time, rather than generic formulas. It adjusts automatically as your metabolism changes, where a traditional TDEE calculator can miss by several hundred calories a day and never corrects itself.
How is adaptive TDEE different from regular TDEE calculators?
Traditional TDEE calculators use formulas (like Mifflin-St Jeor or Harris-Benedict) that estimate your calorie burn based on height, weight, age, and activity level. These can be inaccurate because they cannot account for individual metabolic differences, muscle mass, genetics, or metabolic adaptation. Adaptive TDEE uses your actual body data to calculate what you are truly burning, making it significantly more accurate.
How long does it take for adaptive TDEE to be accurate?
Adaptive TDEE calculations become reasonably accurate after 2-3 weeks of consistent daily tracking of weight and calorie intake. For maximum accuracy, 4-6 weeks of data is recommended. The longer you track, the more precise your TDEE becomes as it captures your true metabolic patterns.
Is adaptive TDEE better for weight loss?
Yes, adaptive TDEE is superior for weight loss because it automatically accounts for metabolic adaptation: the slowdown in calorie burn that comes with dieting. Traditional calculators assume your TDEE stays constant, but adaptive TDEE tracks the actual changes in your metabolism and adjusts accordingly, helping you avoid plateaus and maintain consistent progress.
Can I use adaptive TDEE for bulking?
Yes. Adaptive TDEE works well for bulking because it helps you calculate the precise calorie surplus needed for muscle gain without excessive fat gain. As you gain weight and your TDEE increases, adaptive tracking automatically adjusts your targets to keep you in the optimal surplus range.
What is the nSuns adaptive TDEE method?
The nSuns (or 3-Suns) spreadsheet is a community-built sheet that made adaptive TDEE popular on Reddit. You log daily weight and calories, and it solves for the calorie burn that explains your weight trend. It is still a good option if you prefer tracking by hand.
Do I need special equipment for adaptive TDEE?
You only need a basic scale for daily weigh-ins and a way to track your food intake. For the easiest experience, apps like Zolt can automatically sync your weight from smart scales and health apps (Apple Health, Health Connect) and calculate your adaptive TDEE automatically. Alternatively, you can use free spreadsheets or calculators.
Let Zolt do the arithmetic
Log your food and step on the scale. Your target updates itself.