βοΈ BMI Weight Loss Calculator
Your healthy weight range, pounds to goal, and a realistic timeline.
Targets for planning only. Aim for 1 to 2 lb per week and check with a clinician before starting.
Forget vague goals like "lose some weight." Your healthy BMI range converts directly into a target weight range, and the gap between that and the scale is your real number. This calculator takes your height and current weight, works out your BMI, and tells you exactly how many pounds sit between you and a BMI of 24.9, plus how long that takes at safe weekly rates.
How to Use This Calculator
Enter your height and current weight. The calculator finds your BMI, your healthy weight range, and the pounds you need to lose to reach the top of that range.
Enter height and current weight in imperial or metric. Weigh yourself in the morning, after the bathroom, before eating, for the most consistent number.
Read your healthy weight range: the weights that put your BMI between 18.5 and 24.9. The mid-range target (BMI 21.7) suits most people as a long-term goal.
Pick a weekly rate. One to two pounds a week is the evidence-backed safe zone. The calculator converts your total into weeks at 1, 1.5, and 2 pounds per week.
Turn the timeline into a daily plan with our calorie deficit planner, which builds your calorie target from your TDEE.
The Math: From BMI Bands to Pounds
The WHO healthy BMI band is 18.5 to 24.9, and since BMI is just weight over height squared, you can solve backward: multiply each band edge by your height squared to get the matching weights. The top of the band (24.9) is the nearest milestone, the middle (about 21.7) is a comfortable long-term target for most adults, and the bottom (18.5) is a floor, not a goal. One pound of body fat stores roughly 3,500 kcal, so losing a pound a week needs about a 500 kcal daily deficit, which is where the timelines come from.
A warning about the 3,500 rule: it is a decent planning approximation, not a law. Metabolic adaptation means real loss slows as you get lighter, so treat the week counts as minimums. People with more to lose move faster early on; the last ten pounds always crawl. That is normal physiology, not failure.
Worked Example
Height 5 foot 6 (66 inches), weight 190 pounds. BMI = 703 x 190 / 66^2 = 30.7, obesity range. Healthy weight range: 18.5 x (1.676 m)^2 = 52.0 kg to 24.9 x (1.676 m)^2 = 70.0 kg, or 114.6 to 154.3 pounds. Pounds to reach BMI 24.9: 190 - 154.3 = 35.7 pounds. At 1 pound a week that is about 36 weeks; at 1.5, about 24 weeks; at 2, about 18 weeks. The mid-range target (BMI 21.7) is 134.5 pounds, which would mean losing 55.5 pounds total. My take: aim for the 24.9 milestone first, stabilize there for a month, then decide whether the middle of the range is worth chasing.
Setting a Target You Will Actually Hit
The most common mistake is targeting the bottom of the healthy range on day one. A 5-foot-6 person at 190 pounds staring at 114.6 pounds sees an 8-month mountain and quits by February. Aim at the top of the range instead: 154.3 pounds is a real, reachable milestone, and every pound below 190 already improves blood pressure, blood sugar, and joint load. Research consistently shows that losing 5 to 10 percent of body weight delivers most of the health benefit, so the first 10 to 19 pounds here matter more than the last 10.
Also know what BMI cannot see. If you lift weights and carry real muscle, the healthy range may sit too low for you; pair this with a body fat reading before deciding your target. And if your BMI is already under 25, this calculator's job is done: your target is maintenance, and our TDEE calculator gives you the number to eat at.
What a Safe Timeline Looks Like
One to two pounds a week, from a daily deficit of 500 to 1,000 kcal split between eating a bit less and moving a bit more. Faster than that and you start burning meaningful muscle, feeling terrible, and rebounding: very-low-calorie crash diets have dismal 1-year maintenance rates. Slower than half a pound a week is fine too if that is what you can sustain, because the diet you can keep for a year beats the perfect one you keep for three weeks. Protein around 0.7 to 1 gram per pound of body weight plus strength training 2 to 4 times weekly protects muscle while the fat comes off. For the full calorie plan behind the timeline, see our macro calculator.
For informational purposes only, not medical advice. Consult a healthcare professional.
Frequently Asked Questions
How much weight should I lose to reach a healthy BMI?
Subtract the top of your healthy weight range (BMI 24.9 for your height) from your current weight. That is the minimum meaningful target. For example, at 5 foot 6 and 190 pounds, the healthy range tops out at 154.3 pounds, so the target is 35.7 pounds. Enter your numbers above for your exact figure.
What BMI should I target for weight loss?
Target BMI 24.9 first, the top of the healthy range. It is the closest milestone and captures most of the health benefit. Once stable there, many people aim for the middle of the range around BMI 21 to 22. Do not target 18.5; that is a floor, not a goal.
How fast can I safely lose weight?
One to two pounds per week, which needs a daily deficit of roughly 500 to 1,000 kcal. Faster loss costs more muscle, feels worse, and rebounds more often. People with more to lose can sustain the higher end; the last ten pounds always come off slowest.
Is the 3,500 calorie rule accurate?
Approximately. A pound of body fat stores about 3,500 kcal, so a 500 kcal daily deficit predicts a pound a week. In practice, metabolic adaptation slows loss as you get lighter, so treat it as a planning estimate and expect the real timeline to run a bit longer.
Why does weight loss slow down over time?
Three reasons: a lighter body burns fewer calories doing everything, the calorie deficit shrinks if intake stays fixed, and the body adapts by becoming slightly more efficient. The fix is recalculating your calorie target every 10 to 15 pounds lost, not slashing intake further each stall.
Should I lose weight if my BMI is already under 25?
Probably not for health reasons, unless a clinician advises it for a specific condition. Below BMI 25 the goal is maintenance: eat at your TDEE, keep protein up, and train. Chasing a lower number past healthy usually costs muscle and sanity for no health gain.
Does BMI work for setting weight loss goals if I am muscular?
Only loosely. BMI cannot tell muscle from fat, so a muscular person can be "overweight" by BMI while lean. If you lift seriously, set your target from body fat percentage instead: for most men 12 to 18 percent and most women 20 to 26 percent are athletic-healthy zones.
What is a realistic weight loss goal for 3 months?
At 1 to 2 pounds a week, 12 to 24 pounds in 3 months. The honest answer for most people lands around 12 to 15 pounds of fat, because life interrupts perfect weeks. Anyone promising 40 pounds in 3 months is selling something.
How do I keep the weight off after reaching my goal?
Maintenance is its own phase: raise calories gradually back to your new TDEE over 2 to 4 weeks, keep weighing yourself weekly, keep protein high, and keep training. People who maintain successfully keep monitoring; the scale is an early-warning system, not a judgment.
Do I need to count calories to hit my BMI target?
It helps enormously at first, because most people underestimate intake by 30 to 50 percent. You do not need to count forever: a few weeks of honest tracking calibrates your eye, and many people then maintain on habit. If tracking triggers disordered patterns, work with a dietitian instead.