Weight Loss Calculator: Calorie Deficit and Goal Date
Plan your weight loss in numbers. Enter your goal weight and how fast you want to lose it, and get your daily calorie target, the deficit behind it and the date you could reach your goal.
Your results
| Maintenance (TDEE) | 2759 kcal |
| Daily deficit | -550 kcal |
| Time to goal | 16 weeks |
| Maintenance at goal weight | 2635 kcal |
How it works
- 1We estimate your maintenance calories (TDEE) with the Mifflin-St Jeor equation and your activity level.
- 2Each kilogram of body weight lost is counted as about 7,700 kcal, so your weekly pace sets the daily deficit.
- 3We flag paces above 1% of body weight per week and calorie targets that drop too low.
How the goal date is calculated
Daily calories = maintenance (TDEE) minus weekly pace x 7,700 / 7. At 0.5 kg a week that is a deficit of 550 kcal a day. Example: a 30-year-old, 180 cm, 90 kg man with moderate activity has a TDEE of about 2,914 kcal, so eating about 2,364 kcal a day reaches 80 kg in about 20 weeks.
Where these numbers come from
Maintenance calories use the Mifflin-St Jeor equation. The 7,700 kcal per kg rule is a planning figure: research by Kevin Hall and colleagues shows real loss slows over time because energy needs fall with body weight, so treat the date as the earliest realistic one. The CDC recommends a gradual pace of about 1-2 lb (0.5-1 kg) a week. Not medical advice; see a doctor before dieting if you have a health condition, are pregnant or have a history of eating disorders.
Frequently asked questions
How long will it take to reach my goal weight?
Divide the weight you want to lose by your weekly pace. Losing 10 kg at 0.5 kg a week takes about 20 weeks; real progress usually slows a little near the end.
How big should my calorie deficit be?
A deficit of about 400-550 kcal a day gives roughly 0.4-0.5 kg of loss per week, a pace most people can keep while holding on to muscle.
What is a safe rate of weight loss per week?
About 0.5-1 kg (1-2 lb) per week, or 0.5-1% of body weight, is the usual recommendation. Faster loss is harder to keep off and costs more muscle.
Why is my weight loss slower than the calculator says?
As you lose weight your maintenance calories fall, and water shifts hide fat loss for days at a time. Recalculate every few kilograms and judge the trend over 2-3 weeks.
Using the result
What the number is
An estimate for an average person with your height, weight, age, sex and activity. The Mifflin-St Jeor equation behind it is accurate to roughly plus or minus ten percent for most people: close enough to start, never close enough to argue with the scale.
How to use it
Eat at the calculated intake for two to three weeks and weigh yourself under the same conditions. If the trend is not moving the way you want, adjust the intake by a few hundred calories rather than recalculating from scratch.
When to stop guessing
If you have been adjusting for months without progress, the missing piece is usually training and accountability rather than a better number. That is what a coach on Trainera does.
What this calculator cannot know
This calculator works from height, weight, age, sex and activity, which is most of the picture and not all of it. It does not know your training history, your medication, your thyroid, how well you sleep, how much you actually move outside training, or how honestly you log food. Treat the output as a starting estimate: pregnant and breastfeeding women, children, competitive athletes at very low body fat and anyone managing a medical condition should get a number from a doctor or dietitian instead of from a form. Nothing here is medical advice.
Related calculators
Turn these numbers into a real plan
Train on your own with Trainera's free workout and diet tracker, or get matched with a certified personal trainer who builds your plan around these numbers.