Ideal Weight for Seniors: Age Is Not in the Math

There is no American ideal weight for older adults. The NIDDK publishes a single BMI table for adults ages 20 and older — one table for a 22-year-old and a 92-year-old — and none of the classic ideal body weight equations has an age term in it at all.

The “60 or older” checkbox widens the output to a BMI band of 22 to 27, a range used in some geriatric nutrition practice but not published by any US federal agency. Leave it unchecked to see the official adult band; tick it to see how much a wider band would change the answer.

What each band works out to

Height	Adult band (BMI 18.5–24.9)	Wider band (BMI 22–27)
5 ft 2 in	102–136 lb	120–148 lb
5 ft 4 in	108–145 lb	128–157 lb
5 ft 6 in	115–154 lb	136–167 lb
5 ft 8 in	122–164 lb	145–178 lb
5 ft 10 in	129–174 lb	153–188 lb
6 ft 0 in	137–184 lb	162–199 lb

The gap is not small. At 5 ft 6 in, 130 lb is comfortably mid-range on the official table and below the floor of the wider one. Which band you use changes the label on the same body, which is a good reason to treat both as screens rather than verdicts. The evidence behind the wider band, and what it does and does not establish, is covered in ideal BMI by age.

The formulas cannot age

Run Devine’s equation for a man of 5 ft 9 in: 50 + 2.3 × 9 = 70.7 kg, or 156 lb. Run it again for the same man sixty years later and it returns 156 lb, because the only inputs are height and sex. Robinson, Miller and Hamwi are the same — straight lines in height, with no place to put a birth year.

That is not an oversight. These equations were written to standardize drug doses, and a standardized dose does not want a variable that drifts. It does mean that using one as a personal target after 60 is asking a dosing tool a question it has no vocabulary for.

What changes after 60 is composition, not the target

The scale can stay flat for a decade while the body underneath it rearranges. StatPearls describes sarcopenia — progressive loss of muscle mass, strength and function — as affecting roughly 5 to 13 percent of adults over 60 and 11 to 50 percent of those over 80, driven mainly by loss of type II muscle fibers. When muscle leaves and fat replaces it at the same total weight, the condition is called sarcopenic obesity, and a normal BMI hides it completely.

So the useful question after 60 is rarely “am I inside the band”. It is whether grip is weaker, whether standing up from a chair takes hands, whether walking pace has slowed. None of that shows up in pounds.

Measure the height again before you trust the range

Because the range is height squared, a shrinking measurement quietly moves the target. Lose an inch and the top of the healthy band falls by four to five pounds; Devine’s single number falls by 5.1 pounds exactly, at every height. A person whose “ideal weight” appears to drop every few years is usually watching their spine compress, not their requirements change.

Measure barefoot against a wall, heels together, and record the date. If posture makes a standing measurement unreliable, clinicians use alternatives such as knee height or arm span rather than guessing.

What is worth bringing to an appointment

A weight trend beats a weight. Unintentional loss, appetite that has faded, clothes hanging differently — those carry more information at 75 than any row of a table, and they are worth raising even when the number still lands inside the band. For the arithmetic behind every band on this page, see the ideal weight calculator.

This content is informational and does not replace evaluation by a health professional.