Weight Loss Time Calculator
By Rick Campbell · Updated · Sourced to primary literature · Not medical advice
The deficit calculator answers what to eat today. This page answers how long each safe speed takes, after the same rails have spoken: never faster than 1% of bodyweight a week, never below 80% of estimated TDEE, never below 1,500 kcal for men or 1,200 for women, and never toward a goal below BMI 18.5.
The table is a range, not a calendar. Adaptive expenditure, water and a falling bodyweight all make late weeks slower than the first ones. We do not print a finish date, because a date implies the rate will hold exactly, and it will not.
Enter height, weight, age, sex, activity and a goal. You get weeks at four paces, the daily calories that survive the rails, protein at 2.2 g/kg, and a link that carries the numbers into the deficit and macro calculators. If a rail binds, the weeks use the slower actual rate, which is the only version of this answer that matches what you can eat.
In brief
- Safe paces on this site are 0.25, 0.5 and 0.75 kg a week, plus a 1% of bodyweight cap.
- The calorie target at each pace uses the same rails as the deficit calculator, so the weeks you see are weeks that this site will actually plan.
- A finish date is not computed. Late kilograms usually take longer than the linear table.
- Protein while cutting sits at 2.2 g per kilogram to protect lean mass.
Calculator
What you'll see here
A table of weeks at 0.25, 0.5, 0.75 and 1% of bodyweight per week, each daily calorie target after the safety rails, protein, and a link that carries your numbers into the deficit calculator.
Why a pace table is not a countdown
Most 'how long to lose 20 pounds' pages multiply the kilograms by 7,700, divide by a deficit, and print a date. That arithmetic assumes expenditure stays put and the body does not respond. Hall and colleagues showed that a static 3,500 kcal per pound rule can predict about twice the annual loss a dynamic model does.
This site already refuses to print a goal date on the deficit page. This calculator still answers the search: it shows weeks at each allowed rate, then says the last weeks will slip. That is the honest version of the same question.
If a rail binds, the actual weekly kilograms fall and the weeks rise. The table names which rail fired. That is the difference between a plan you can hold and a plan a crash-diet site would sell.
The four paces, and the 1% cap
Gentle (0.25 kg a week) is the pace most people can live with for months. Steady (0.5 kg) is the usual first plan. Brisk (0.75 kg) is for a shorter block when the calorie maths still clears the floors. The fourth row is 1% of current bodyweight, the fastest rate this engine will compute.
At a high starting weight, 1% can be more than 0.75 kg. At a lighter weight, 1% is smaller than 0.75 kg, so the brisk row is the one the cap clips. Both cases are shown rather than hidden behind a single default.
Clinical programmes often treat 5% and 10% of starting weight as the first meaningful marks. The weight-change calculator tracks those. This page only answers duration at a safe speed.
How the daily calories are chosen
Maintenance is Mifflin-St Jeor times the activity factor you pick. A requested weekly rate becomes a daily deficit using 7,700 kcal per kilogram. That intake is then lifted if it would fall through 80% of TDEE or through the sex-specific floor.
When a rail binds, the weeks use the actual weekly kilograms after the rail, not the rate you asked for. Printing the asked rate and then ignoring the floor would be the dishonest version of this tool.
Activity is the usual source of error. Most people pick one level too high. If the weeks look short, drop a level and read the table again.
Why late weeks take longer
As weight falls, basal metabolism falls with it. Non-exercise movement often falls too. The same intake that produced 0.5 kg a week in month one may produce 0.3 kg in month four. That is expected, not a broken thyroid.
Water and glycogen can hide a fortnight of fat loss after a salty meal, a hard training week or a menstrual cycle. Use a seven-day average, not a morning panic.
The check-in calculator compares expected kilograms from your logged intake with the scale. Use that when the weeks on this page stop matching the bathroom.
Protein while the weeks run
A deficit will take tissue from somewhere. Protein plus resistance training is what steers that toward fat. This result shows 2.2 g per kilogram, the upper edge used on the deficit page while cutting.
If that gram target plus a fat floor will not fit the calorie target, the calorie target is too low for your size. The rails exist to catch that before you try to eat it.
The macro calculator will place the same protein figure inside the daily calories from the row you choose.
What to do with the number
Pick the slowest pace you can still care about. Adherence beats a short table. Carry the row into the deficit calculator, then into macros, then walk the check-in every two to four weeks.
If the goal sits above the healthy BMI range, treat it as a first stop, not a finish. If it sits below BMI 18.5, this page refuses the table and says so.
Children and teenagers are out of scope. Adult energy maths does not run under 18 on this site. If you are planning for someone else, run their own height, weight and activity, not yours, and do not share a calorie target across two bodies.
How it's calculated
Requested daily deficit
Daily deficit (kcal) = requested kg/week × 7,700 ÷ 7
7,700 kcal/kg is the planning constant used across this site, from Wishnofsky's 3,500 kcal/lb expressed per kilogram.
Intake after rails
Daily kcal = max(TDEE − deficit, 0.8 × TDEE, sex floor)
Sex floor is 1,500 kcal (male) or 1,200 kcal (female). Goal below BMI 18.5 is rejected.
Weeks
Weeks = (current kg − goal kg) ÷ actual kg/week after rails
A range, not a date. Adaptive TDEE makes late weeks longer.
Worked example: 80 kg, 178 cm, 35-year-old man, sedentary, goal 72 kg
- Mifflin BMR = 10×80 + 6.25×178 − 5×35 + 5 = 1,742.5 kcal.
- Sedentary TDEE = 1,742.5 × 1.2 = 2,091 kcal.
- A 0.5 kg/week ask wants 550 kcal/day off, which is 1,541 kcal.
- 80% of TDEE is 1,672.8 kcal, so the deficit rail lifts the target to 1,673 kcal.
- Actual weekly loss becomes about 0.38 kg, so 8 kg takes about 21 weeks, not the 16 weeks a raw 0.5 kg/week would claim.
Where this number is used in the real world
- Choosing between a gentle cut and a shorter block before a season.
- Checking whether a goal is even reachable at a safe rate.
- Seeing which safety rail would bind before you start.
- Handing a chosen pace to the deficit and macro calculators.
- Explaining to someone else why a crash-diet date is not on this site.
Frequently asked questions
Why will you not give me a finish date?
A date implies the weekly rate will hold exactly for months. Expenditure falls as you get lighter, water hides fat for weeks, and logged intake is usually short of the truth. Weeks at each safe pace, with the rails named, is the number you can plan from. A countdown is the number crash-diet sites sell.
Is 1% of bodyweight a week safe for everyone?
It is the fastest rate this engine will compute, taken from common clinical practice for medically supervised loss, not a target for a first attempt at home. Most people do better at 0.25 to 0.5 kg a week. If the 1% row is clipped by the calorie floor, the floor is the thing to obey, not the percentage.
What if my goal is below the healthy BMI range?
The table is refused. A BMI of 18.5 is the bottom of the WHO healthy range for height, and this site will not plan a cut that finishes under it. If a clinician has set a different target for a medical reason, that conversation belongs with them, not with a web form.
Does this include exercise calories?
Only through the activity factor on TDEE. Do not subtract a tracker session on top of that, or you double-count the same movement. If you walk more, raise the activity level one notch and re-read the table rather than stacking session calories onto the deficit. The walking and calories-burned pages exist to compare sessions, not to be subtracted twice.
Why is protein so high on a time calculator?
Because the weeks only matter if the mass you lose is mostly fat. 2.2 grams per kilogram is the cutting tier used on the deficit and protein pages. It is insurance for lean mass, not a hypertrophy programme, and it costs nothing but ordinary food choices at the fridge each day.
How often should I re-run this?
Every 4 to 6 weeks, or after a 3% change in weight. The TDEE underneath is computed from current weight, so the weeks and the calories both move when you do. The check-in calculator tells you whether the logged intake is matching the scale between those re-runs, which is the better weekly habit.
Keep going
A single number rarely tells the whole story. Alongside the weight-loss time result, the calorie deficit calculator, the TDEE calculator, the energy in fat calculator and the macros calculator each add a different angle on the same measurements. For the reasoning behind the numbers, read How long loss takes and Adaptation and plateaus.
Sources
- Hall KD, Sacks G, Chandramohan D, et al. Quantification of the effect of energy imbalance on bodyweight. Lancet 2011;378:826–37. doi.org/10.1016/S0140-6736(11)60812-X
- Wishnofsky M. Caloric equivalents of gained or lost weight. Am J Clin Nutr 1958;6:542–6. doi.org/10.1093/ajcn/6.5.542
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr 1990;51:241–7. doi.org/10.1093/ajcn/51.2.241
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- Campbell, R. (2026). Weight Loss Time Calculator. Body Stats. https://bodystats.co/app/weight-loss-time-calculator
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- “Weight Loss Time Calculator”, Body Stats, last updated 15 September 2026, https://bodystats.co/app/weight-loss-time-calculator
Every formula and threshold on this page is written out with its primary source on our methodology page. These results are informational and educational, not a diagnosis or a substitute for professional advice. See the medical disclaimer.
Last updated . Written by Rick Campbell; not medically reviewed. See review status.