TDEE calculator

Every activity level, on your numbers

This is the table worth reading twice. The same body, the same equation, and a spread of roughly a thousand calories between the top row and the bottom one. Choosing a level one step too high is how a carefully calculated deficit quietly becomes maintenance.

How the number is built

Your resting rate comes first, from the Mifflin St Jeor equation, which takes weight, height, age and sex. It is the cost of being alive and doing nothing: breathing, pumping blood, holding temperature. For most people it is 60 to 70% of the whole day.

That resting figure is then multiplied by an activity factor covering everything else. Training is the loud part of it and usually not the big part. Walking, standing, fidgeting and carrying things add up to more than most people's gym sessions do, which is why someone with a physical job outburns a desk worker who trains five times a week.

Digestion takes a cut too, around 10% of what you eat, and it is already folded into the multipliers rather than shown separately.

Using it without fooling yourself

The calculated figure is where you start, not what you are. Eat at it for two weeks, weigh yourself at the same time each morning, and take the average of each week. If the averages are flat, the estimate was right. If you are losing half a kilo a week and did not mean to, your real expenditure is about 500 kcal higher than the page said.

Two weeks is the shortest window that survives a normal amount of water weight. A single morning tells you what you drank and whether you ate salt, and almost nothing about fat. There is more on that in the guide to why weight fluctuates.

Sources

• A new predictive equation for resting energy expenditure in healthy individuals (Mifflin St Jeor), American Journal of Clinical Nutrition, 1990
• Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults, Journal of the American Dietetic Association, 2005
• Human energy requirements: report of a joint FAO, WHO and UNU expert consultation, Food and Agriculture Organization, 2004
• Non exercise activity thermogenesis (NEAT), Best Practice and Research Clinical Endocrinology and Metabolism, 2002
• Diet induced thermogenesis, Nutrition and Metabolism, 2004

How this was made

Written by Abdullah Javaid, founder of Calfit, drafted with AI assistance and edited by hand. The resting rate comes from the Mifflin St Jeor equation using weight, height, age and sex, and each activity level multiplies it by a standard factor from 1.2 to 1.9. The fat loss and build figures are 20% under and 10% over that total.

Quick questions