There is no single "should"
People want one number, and every tool that gives you one is guessing at a level of precision that doesn't exist. Two people the same height can both be perfectly healthy 20 lb apart. What you actually want is a healthy weight range for your height, and then a sense of where in that range makes sense for you.
Method 1 — your healthy weight range by height
The most widely used definition of a healthy weight is the span that puts you at a BMI between 18.5 and 24.9 for your height. Multiply each of those numbers by your height in metres squared, and you get the bottom and top of your range.
| Height | Healthy weight range (BMI 18.5–24.9) |
|---|---|
| 5 ft 0 in | 97 – 128 lb |
| 5 ft 4 in | 110 – 145 lb |
| 5 ft 8 in | 125 – 164 lb |
| 6 ft 0 in | 140 – 184 lb |
| 6 ft 4 in | 156 – 205 lb |
The ideal weight calculator shows this range for your exact height, marks where your current weight falls, and tells you how far you are from the nearest edge.
Method 2 — the ideal weight formulas
Before BMI ranges caught on, doctors used single-number formulas. Four are still quoted. They all follow the same shape — a base weight at 5 ft, plus a fixed amount for every inch above that — and differ only in the constants.
| Formula | Year | Notes |
|---|---|---|
| Hamwi | 1964 | Built for dietitians; the most generous of the four |
| Devine | 1974 | Created for drug dosing; the most cited in medicine |
| Robinson | 1983 | From revised insurance-company weight tables |
| Miller | 1983 | Same 1983 data; the most conservative |
For the same person the four land within about 5–10 lb of each other — and all of them fall inside the BMI healthy range. That's the useful way to read them: not as competing answers, but as four points near the middle of your range.
Where to aim within the range
Once you know your range, three things decide where in it to aim.
- Frame size. Bigger-boned people carry more weight as bone and structural muscle. Measure your wrist just below the bone: for men, under 6.75 in is small and over 7.5 in is large; for women it's under 5.5 in and over 5.75 in. A large frame points to the upper third of the range.
- Muscle. If you lift or play sport, you'll sit higher in the range — or above it — at the same body fat as someone sedentary. That's muscle weight, not a problem.
- How you feel and perform. Energy, training, sleep and bloodwork matter more than the exact figure. If those are good and you're inside the range, you're at a healthy weight.
How much should I weigh for my age?
The adult healthy weight range doesn't change with age, and none of the ideal weight formulas use age. What changes is body composition: after about 30, most people slowly lose muscle and gain fat even if the scale holds steady. So an "ideal" weight at 55 can hide more fat than the same weight did at 25. If you're older, check a body fat percentage alongside the number — it catches the shift the scale misses.
How much should I weigh for my height and gender?
Height sets your range. The formulas apply a sex difference — women get a base weight about 10 lb lower than men at the same height, reflecting average differences in frame and muscle. But the BMI healthy range itself is not adjusted for sex, so a 5 ft 6 in woman and a 5 ft 6 in man have the same range on paper — the woman will typically sit lower in it.
When the number is misleading
Any height-and-weight method is blind to two things that matter: how much of your weight is muscle, and where your fat is stored. A lean, trained person often reads as "over" their ideal weight while carrying very little fat. An older adult who has lost muscle can read as "ideal" while carrying too much. And fat around the waist raises health risk more than the same weight carried elsewhere — a waist over 40 in for men or 35 in for women is the usual flag. Use your weight range as a sanity check, and a body fat estimate plus a tape measure for the fuller picture.
Turning a number into a plan
If you've decided to move toward a target inside your range, the next question is how. Our calorie calculator takes your goal weight and turns it into a daily calorie target, a realistic weekly rate, and a projected timeline — so the plan is arithmetic, not guesswork.
Frequently asked questions
How much should I weigh for my height?
Use the healthy weight range — the weights that put you at a BMI of 18.5 to 24.9 for your height. A 5 ft 4 in person has a range of about 110–145 lb; at 5 ft 10 in it's about 129–174 lb. Anywhere inside your range is a healthy weight.
How much should I weigh for my age?
The healthy range is the same at every adult age. Body composition changes over time, so pair the number with a body fat estimate as you get older rather than adjusting the target.
What is the ideal weight for a woman?
It depends on height. As a guide, the Devine formula gives 100 lb at 5 ft plus about 5 lb per inch above that, so a 5 ft 6 in woman is near 130 lb — within a healthy range of roughly 115–154 lb.
Is BMI or an ideal-weight formula better?
The BMI range is what health bodies use and it gives you a band rather than a single figure, so it better reflects that healthy weight isn't one number. The formulas are a quick single estimate. Best is to see them together — a range with the formula points marked inside it.
My weight is "ideal" but I don't look lean — why?
Height-and-weight methods can't see body composition. If you've lost muscle over the years, or never built much, you can be at an ideal weight while carrying more fat than is healthy. A body fat percentage and a waist measurement will show it.