Weight loss rate
calculator

Set your loss rate as a percent of bodyweight, not a flat 1–2 lb/week. You get the weekly loss, the daily calorie deficit it needs, and whether the rate sits in the range that holds onto muscle.

What a safe weight loss rate is

A sustainable loss rate is 0.5–1% of your bodyweight per week — the range that lets you lose fat while holding onto muscle (Helms, Aragon & Fitschen 2014). At 200 lb (90.7 kg) that's about 1 to 2 lb (0.45–0.91 kg) a week; at 150 lb (68 kg) it's 0.75 to 1.5 lb (0.34–0.68 kg). The percent is the point: a flat "2 lb a week" is a different diet for a 130 lb person than for a 300 lb one, and only one of them is inside the muscle-sparing band.

This calculator takes your bodyweight and a target rate, then returns the weekly loss and the daily calorie deficit that produces it — using the same 3,500 kcal-per-pound figure as the calorie deficit calculator (Wishnofsky 1958).

How the math works

The weekly loss is a straight percentage of bodyweight. The deficit that drives it comes from the energy content of a pound of loss — about 3,500 kcal (Wishnofsky 1958), the same rule the deficit page uses.

The last line is the one generic calculators skip. Run a flat 2 lb/week through it: at 200 lb it's 1.0%, at 130 lb it's 1.54% (aggressive), and at 300 lb it's 0.67% (moderate). Same number on the scale, three different diets — which is why the rate belongs in percent.

Where the 0.5–1% band comes from

Helms, Aragon & Fitschen (2014) reviewed the physique-sport literature and set the muscle-retaining band at 0.5–1% of bodyweight per week. Garthe et al. (2011) tested it directly: 24 elite athletes, all doing four resistance sessions a week, split into a 0.7%/week group and a 1.4%/week group. Both lost a similar amount of fat, but lean body mass rose 2.1% in the slow group and didn't move (−0.2%) in the fast group. Same fat loss; the faster group paid for the speed in muscle.

Worked example

A person starting a cut at 200 lb (90.7 kg), setting the rate at the recommended 0.7% of bodyweight per week.

• Weekly loss: 200 × 0.7 / 100 = 1.4 lb (0.635 kg)
• Daily deficit needed: 1.4 × 3,500 / 7 = 700 kcal/day
• The four reference rates here: 0.5% → 1.0 lb (0.45 kg) / 500 kcal; 0.7% → 1.4 lb (0.635 kg) / 700 kcal; 1.0% → 2.0 lb (0.91 kg) / 1,000 kcal; 1.4% → 2.8 lb (1.27 kg) / 1,400 kcal
• To lose 20 lb (9.1 kg) at 0.7%: a linear 14.3 weeks at the starting rate — but a percent-of-bodyweight rate slows as you get lighter, so the honest figure is 15.0 weeks (see below)

When this calculator is wrong

A percent-of-bodyweight rate is a ceiling that keeps muscle on, not a target to max out. Past about 1% a week, the extra speed comes almost entirely out of lean mass, not fat. Garthe et al. (2011) is the direct test: the 0.7%/week and 1.4%/week groups lost a similar amount of fat, but lean body mass rose 2.1% in the slow group and was flat (−0.2%) in the fast group. Doubling the rate didn't double fat loss — it bought lean-mass loss. The counter-case is the person carrying a lot of fat: the body can fuel a larger deficit from fat stores, so early in a cut a rate at or a little above 1% can still be mostly fat. The leaner you get, the more the low end of the band matters.

• A fixed percent slows as you lighten. The rate applies to your current bodyweight, so the absolute weekly loss shrinks as the scale drops. Losing 20 lb from 200 lb at 0.7% is a linear 14.3 weeks but a geometric 15.0 — and the gap widens the more you set out to lose. The linear timeline is a floor, not a promise.
• The bands were validated on trained, lean athletes. Helms 2014 and Garthe 2011 studied physique and elite athletes who lift. If you're not training — especially not doing resistance work — more of any loss comes from muscle at any rate, and protein and lifting matter more than the exact percent.
• The 3,500-kcal deficit is a short-term approximation. Past 4–8 weeks the body adapts and the same deficit yields less (Hall et al. 2011). The calorie deficit calculator flags where that rule stops holding.

What to do with the result

Pick a rate in the 0.5–1% band, take the daily deficit it gives you, and treat it as a two-week experiment. Track intake and weight for two weeks and average the scale — the first week is noisy from water, glycogen, and gut contents. If the average is falling near the predicted rate, the number is right. If it's falling faster, you're above your intended percent and closer to the lean-mass-loss end; ease the deficit up a little.

Lift and eat protein while you do it — that's what decides whether the loss is fat or muscle. On a cut, protein rises to about 2.3–3.1 g/kg of lean body mass (Helms et al. 2014); the protein calculator works out the grams, and the calorie deficit calculator turns the deficit into a daily intake target once you know your maintenance from the TDEE calculator.

Common questions

What is a safe rate of weight loss per week?

As a percent of bodyweight, 0.5–1% per week is the range that holds onto muscle (Helms 2014). That works out to roughly 1–2 lb (0.45–0.91 kg) a week for a 200 lb person, but less for a lighter one — which is why the percent is a better guide than a flat pound figure.

Why use a percent instead of pounds per week?

Because a flat number ignores your size. Two pounds a week is 1.0% of bodyweight at 200 lb, 1.54% at 130 lb, and 0.67% at 300 lb. The lighter person is on a much steeper cut at the identical scale figure. The percent tells you which diet you're actually running.

Will losing weight faster cost me muscle?

Past about 1% of bodyweight a week, largely yes. In Garthe et al. (2011), athletes losing 1.4%/week and 0.7%/week lost a similar amount of fat, but only the slower group gained lean mass — the faster group's was flat. The extra speed came out of muscle, not fat. The exception is someone with a lot of fat to lose early in a cut.

How do I turn a target rate into calories?

Multiply the weekly loss in pounds by 3,500 and divide by 7 for the daily deficit (Wishnofsky 1958). A 1.4 lb/week loss needs a 700 kcal/day deficit. Subtract that from your maintenance calories to get an intake target — the deficit calculator does that step.

Does the rate stay the same as I lose weight?

The percent does, but the pounds don't. A 0.7% rate on a lighter bodyweight is fewer pounds each week, so the loss slows on purpose as you go. That's why a fixed-percent timeline runs a little longer than the naive linear one — 15.0 weeks versus 14.3 in the worked example.

Is a very low bodyweight a reason not to use this?

It's a reason to be cautious. The bands were built on lean, trained athletes with fat to spare for a contest, not on medical weight loss at a low starting weight. If your weight is already low, or loss is being driven by health rather than physique goals, that's a conversation for a dietitian or physician, not a calculator.