WeightSnap Tools / Weight loss percentage calculator
Enter your starting weight and your current weight. This works out the percentage of body weight you've lost, shows the 5/10/15/20/25% milestones, and marks the ones you've already passed.
| Milestone | Weight at milestone | Status |
|---|
Milestones are percentages of your starting weight. About 5% is the threshold the obesity literature calls clinically meaningful.
No calculator needed, it's one line of arithmetic. To figure out the percentage of body weight you've lost, take the weight you lost, divide it by your starting weight, and multiply by 100:
Worked example: you started at 250 lb and you're at 225 lb now. You've lost 25 lb. Divide 25 by 250 and you get 0.10. Multiply by 100 and that's a 10% loss. The formula is identical in kilograms, just keep both weights in the same unit.
Two things people trip on when they work out their percentage: always divide by the starting weight, not the current one, and don't mix units (a start in kg and a current weight in lb will produce nonsense). That's it, the math is the easy part.
Where common starting weights land at each milestone, pre-computed with the same formula. All values in lb.
| Starting weight | −5% | −10% | −15% | −20% | −25% |
|---|---|---|---|---|---|
| 150 lb | 142.5 | 135 | 127.5 | 120 | 112.5 |
| 175 lb | 166.3 | 157.5 | 148.8 | 140 | 131.3 |
| 200 lb | 190 | 180 | 170 | 160 | 150 |
| 225 lb | 213.8 | 202.5 | 191.3 | 180 | 168.8 |
| 250 lb | 237.5 | 225 | 212.5 | 200 | 187.5 |
| 275 lb | 261.3 | 247.5 | 233.8 | 220 | 206.3 |
| 300 lb | 285 | 270 | 255 | 240 | 225 |
| 325 lb | 308.8 | 292.5 | 276.3 | 260 | 243.8 |
| 350 lb | 332.5 | 315 | 297.5 | 280 | 262.5 |
The reason clinicians and studies talk in percent rather than pounds is that the health thresholds are written that way (all figures as of mid-2026):
About 5% is the level the obesity literature usually calls clinically meaningful. Reviews of the trial data tie a 5 to 10% loss to measurable improvements in blood pressure, HDL cholesterol, blood sugar, and quality-of-life measures. On a 250 lb start, that's 12.5 lb, a much closer target than most people assume.
About 10 to 15% is where studies report improvement in harder problems, like obstructive sleep apnea and fatty liver disease. It's also roughly what the first-generation GLP-1 trials averaged: semaglutide 2.4 mg came in around 15% over 68 weeks in STEP 1.
About 20% and beyond was, until recently, bariatric-surgery territory. Tirzepatide 15 mg averaged about 21% over 72 weeks in SURMOUNT-1, and retatrutide (still investigational) averaged about 24% at 12 mg over 48 weeks in its phase 2 trial. Our GLP-1 weight loss calculator applies those trial averages to your own starting weight if you want the milestone-by-milestone view.
One clarification, since the terms get mixed up: this page measures total body weight percentage, not body fat percentage. The scale number includes fat, muscle, and water; composition is a different measurement from a different tool.
Subtract your current weight from your starting weight, divide by your starting weight, then multiply by 100. Example: starting at 250 lb and now at 225 lb is (250 − 225) ÷ 250 × 100 = 10%. The formula works the same in pounds or kilograms, as long as both weights use the same unit.
About 5% of body weight is the threshold the obesity literature usually calls clinically meaningful. Reviews tie 5 to 10% loss to improvements in blood pressure, HDL cholesterol, blood sugar, and quality of life, while larger losses of roughly 10 to 15% are where studies report improvement in conditions like obstructive sleep apnea and fatty liver (as of mid-2026). Whether any target makes sense for you is a conversation with your provider, not this page.
The pace most commonly cited as sustainable in mainstream guidance is roughly 0.5 to 1% of body weight per week, which is the familiar 1 to 2 lb per week for many people. Faster than that tends to cost more muscle and is harder to hold. That figure is general guidance, not a target for you specifically, and weeks will vary a lot around any average.
No. This calculator measures the change in your total scale weight, which includes fat, muscle, water, and everything else. Body fat percentage measures composition, what share of your weight is fat, and needs a different tool (DEXA, calipers, or a smart-scale estimate). You can lose 10% of your body weight while your body fat percentage changes by a different amount.
The pivotal trials reported averages of about 15% of body weight for semaglutide 2.4 mg over 68 weeks (STEP 1), about 21% for tirzepatide 15 mg over 72 weeks (SURMOUNT-1), and about 24% for retatrutide 12 mg over 48 weeks in its phase 2 trial, with retatrutide still investigational as of mid-2026. Those are averages across thousands of participants, not predictions for any one person.
Percentage puts different body sizes on the same scale. Twenty pounds is 13% of a 150 lb starting weight but only 6% of a 320 lb one, which is why researchers and clinicians report results in percent, and why the health-benefit thresholds are written as percentages. Pounds are fine for day-to-day tracking; percent is the number to use when comparing your progress to studies or to anyone else.
WeightSnap is a tracking tool, not medical advice. This calculator does arithmetic on the numbers you enter; the milestone thresholds summarize published research and are informational only. Weight-loss targets and pacing are individual, so always work with your healthcare provider.
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