Weight Loss Calculator: How Long Will Your Cut Take?
Enter your current weight, goal weight and maintenance calories to see a realistic timeline for your cut and the daily calories that match your chosen pace.
Your results
Estimates for healthy adults, for education only. Not a medical assessment. Built and reviewed by Umair Hazrami.
How this calculator works
You give it four things: current weight, goal weight, maintenance calories (TDEE) and a rate of loss. The rate is a percentage of body weight per week: 0.5%, 0.7% or 1%.
Weeks to goal. Your weight is assumed to drop by the same percentage every week, so the loss compounds downward:
- Weeks = ln(goal ÷ current) ÷ ln(1 - rate), rounded up
Starting weekly loss. Current weight × rate.
Daily calorie target. The calculator converts that weekly loss into a daily deficit using 7,700 kcal per kg, then subtracts it from your maintenance:
- Daily deficit = (weekly loss in kg × 7,700) ÷ 7
- Target = TDEE - daily deficit
If the target falls under 1,200 kcal, you get a warning to choose a slower rate.
A worked example
An 80 kg lifter wants to reach 70 kg with a TDEE of 2,500 kcal.
| Rate | Weeks | Starting loss | Daily deficit |
|---|---|---|---|
| 0.5% | ~27 | 0.40 kg/week | 440 kcal |
| 0.7% | ~20 | 0.56 kg/week | 616 kcal |
| 1% | ~14 | 0.80 kg/week | 880 kcal |
At 0.7% that means eating about 1,884 kcal a day. Seven extra weeks at 0.5% feels like a lot. For a lifter it can buy better training and less muscle loss.
Why the default is 0.7%
In a small randomised trial in elite athletes who lifted four times a week, the group targeting 0.7% per week increased lean mass by about 2%, while the group targeting 1.4% per week saw no change (Garthe et al., 2011). A review for natural bodybuilders lands on a similar range, 0.5-1% per week (Helms et al., 2014). Neither is a big dataset, so the deficit guide covers when faster can make sense.
How to use the result
The calorie target is a first guess. Weigh yourself every morning, average the week, and compare that average to the starting loss above. Off by a lot after three weeks? Move calories by 100-200 and check again. Set protein first with the protein calculator, then fill in the rest using the macro calculator.
In Indian kitchens a common leak is cooking oil and ghee, which rarely get measured. Track them before you cut food.
Limitations and who this is not for
The 7,700 kcal per kg rule is a simplification. Modelling suggests the energy cost of each kg lost depends on how much fat you start with: the rule roughly fits people with plenty of body fat but overstates the deficit needed for leaner people (Hall, 2008). Compared against supervised weight loss studies, the static rule also overpredicts how much weight people actually lose over time (Thomas et al., 2013). One reason is that a lighter body burns less, so the same intake produces a smaller deficit. The calculator holds your calorie target fixed at your starting weight, so recalculate with a fresh TDEE every 4-6 weeks. The metabolic adaptation guide explains why.
Choosing a goal weight? South Asians tend to carry more health risk at a given BMI, so Asian BMI cut-offs are lower than the global ones. The BMI calculator shows both.
This tool is not for under-18s, pregnancy or breastfeeding, anyone with a history of eating disorders, or people managing diabetes or other conditions on medication. In those cases, plan any weight loss with a doctor or registered dietitian.
Frequently Asked Questions
How fast should I lose weight if I lift?
A review of natural bodybuilding contest prep recommends losing roughly 0.5-1% of body weight per week to hold on to muscle. In a small trial in elite athletes, the slower group (targeting 0.7% per week) gained lean mass while the faster group did not. That is why 0.7% is the default here, but the data come from small samples, so treat it as a sensible starting point rather than a magic number.
Why does the calculator say my weekly loss will slow down?
The rate is a percentage of your current weight, so 0.7% of 80 kg is 0.56 kg, but 0.7% of 72 kg is only about 0.5 kg. The timeline accounts for this shrinking loss each week. The daily calorie target, though, is set from your starting weight and does not shrink, so recalculate every few weeks.
Is 7,700 calories really equal to 1 kg of fat?
It is a rough rule of thumb, and the research says it is often wrong for individuals. Modelling work suggests leaner people need a smaller deficit per kg lost because more of that weight comes from lean tissue, and comparisons with supervised studies show the static rule overpredicts weight loss over time. Use it to set a starting deficit, then let your weekly scale average tell you the truth.
What does the warning about a very low target mean?
If your maintenance calories minus the deficit lands below 1,200 kcal a day, the calculator flags it. Eating that little makes it hard to get enough protein and micronutrients and is tough to sustain. Pick a slower rate, or speak to a doctor or dietitian before going that low.
Do I really need diet breaks on a long cut?
The calculator suggests adding 1-2 maintenance weeks to long cuts as a practical buffer for life, travel and festival season, not because a break is required. Evidence on whether planned breaks improve fat loss is limited and mixed. Many lifters simply find a long cut easier to stick to with a planned pause.
Where do I get my maintenance calories?
Use the calorie calculator for a starting estimate, then refine it with real data. If your weekly average weight has been stable for two to three weeks while you track honestly, the calories you were eating are your true maintenance. That real number beats any equation.
When should I talk to a doctor before dieting?
See a doctor first if you have diabetes, take medication that affects blood sugar or appetite, are pregnant or breastfeeding, are under 18, or have a history of disordered eating. Also see a doctor if you are losing weight without trying. This calculator plans a deliberate cut; it cannot assess medical risk.
Sources & References
Every claim above is checked against peer-reviewed research (PubMed, U.S. National Library of Medicine) or guidance from established health bodies. How we fact-check.
- Hall KD. What is the required energy deficit per unit weight loss? Int J Obes (Lond). 2008. PMID: 17848938
- Thomas DM, et al. Can a weight loss of one pound a week be achieved with a 3500-kcal deficit? Commentary on a commonly accepted rule. Int J Obes (Lond). 2013. PMID: 23628852
- Garthe I, et al. Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes. Int J Sport Nutr Exerc Metab. 2011. PMID: 21558571
- Helms ER, et al. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. J Int Soc Sports Nutr. 2014. PMID: 24864135