Ideal weight by height · four classic formulas

Ideal weight for a 5'6" (168 cm) woman

Quick answer

At 5'6" (168 cm), the four classic ideal weight formulas give 129 to 135 lb (58.7 to 61.3 kg) for a woman. The weight range for a BMI of 18.5 to 24.9 at this height is 115 to 154 lb.

Lowest of four, Hamwi: 129lb; 58.7 kg
Highest of four, Miller: 135lb; 61.3 kg
Spread between formulas: 6lb; 2.6 kg
BMI 18.5 to 24.9: 115 to 154lb; 52 to 70 kg

Four formulas estimate an “ideal” body weight from height and sex alone. This page works them out for a woman who is 5 ft 6 in, shows the arithmetic, and sets the answers beside the heights around it, 5'3" to 5'9". Treat the numbers as reference points to talk over with a professional, not as a goal.

The four formulas at 5'6"

Each formula is a base weight at 5 ft plus a fixed amount for every inch above it, a little differently for women and men. At 5'6" that is 6 inches above 5 ft.

Ideal weight for a woman at 5'6" (168 cm), by formula
Formula	Arithmetic (kg)	Result	In pounds	Against BMI 18.5 to 24.9
Robinson (1983)	49 + 1.7 × 6	59.2 kg	131 lb	Inside the range
Miller (1983)	53.1 + 1.36 × 6	61.3 kg	135 lb	Inside the range
Devine (1974)	45.5 + 2.3 × 6	59.3 kg	131 lb	Inside the range
Hamwi (1964)	45.5 + 2.2 × 6	58.7 kg	129 lb	Inside the range

How the formulas change around 5'6"

At 5'6" the four formulas give 129 to 135 lb for a woman. The lines show how each formula changes from 5'3" to 5'9"; the shaded band is the weight range for a BMI of 18.5 to 24.9.

Ideal weight for nearby heights, female

Ideal weight in pounds for a woman, 5'3" to 5'9"
Height	Robinson	Miller	Devine	Hamwi	All four
5'3"	119	126	116	115	115 to 126 lb
5'4"	123	129	121	120	120 to 129 lb
5'5"	127	132	126	125	125 to 132 lb
5'6" (this page)	131	135	131	129	129 to 135 lb
5'7"	134	138	136	134	134 to 138 lb
5'8"	138	141	141	139	138 to 141 lb
5'9"	142	144	146	144	142 to 146 lb

What is specific to 5'6"

At 5 ft 6 in the formulas sit 6 inches above their 5 ft starting point. Miller (1983) gives the most at 135 lb (53.1 + 1.36 × 6 = 61.3 kg) and Hamwi (1964) the least at 129 lb (45.5 + 2.2 × 6 = 58.7 kg), a gap of 6 lb. For a woman, each extra inch adds between 3 and 5.1 lb across the four, which is why the gap changes with height.

Against the weight range for a BMI of 18.5 to 24.9, which at this height is 115 to 154 lb: Robinson and Miller and Devine and Hamwi are inside it. The BMI range is 39 lb wide at 5'6", against 6 lb for the four formulas together, so it leaves more room.

One inch shorter, at 5'5", the four formulas give 125 to 132 lb; one inch taller, at 5'7", 134 to 138 lb. For a man at the same 5'6", the same formulas give 140 to 143 lb, because each formula has its own base weight and per-inch step for each sex (see the 5'6" male page).

Ideal body weight formulas were first developed to help clinicians dose medication, not to say how anyone should look. They use height and sex only, so they cannot see your muscle, bone structure, age or health, and a woman of 5'6" can be well outside them for good reasons.

Where the formulas come from

The Robinson (1983), Miller (1983), Devine (1974) and Hamwi (1964) formulas are the ones in our ideal weight calculator, which also takes any height. The weight range for a BMI of 18.5 to 24.9 is weight = BMI × height² for those two BMI values. Full citations are on the sources page, and the arithmetic is explained on how we calculate.

Frequently asked questions

What is the ideal weight for a 5'6" woman?

The four classic formulas give 129 to 135 lb (58.7 to 61.3 kg) at 5'6": Robinson 131 lb, Miller 135 lb, Devine 131 lb, Hamwi 129 lb. They are estimates from height and sex alone, so they are a starting point for a conversation, not a goal.

Why do the formulas give different answers at 5'6"?

Each starts from a different base weight at 5 ft and adds a different amount per inch. At 5'6" that is 6 in above 5 ft, and the formulas end 6 lb apart, from Hamwi at 129 lb to Miller at 135 lb.

What weight range does a BMI of 18.5 to 24.9 give at 5'6"?

115 to 154 lb (52 to 70 kg) at 168 cm. BMI ignores muscle and frame, so it is a screening number, not a diagnosis.

Should I aim for the number on this page?

Not on the strength of a formula. They were written to help dose medication and know nothing about your muscle, frame, age or health. A doctor or registered dietitian can tell you what weight is right for you.

From a number to a daily plan

CalorTracker turns a weight you and your doctor settle on into calorie and macro targets, and logs meals from a photo, your voice or text. Free to start.

Start free on the web

These figures come from formulas that use height and sex only. They are not a medical target and not advice about what you should weigh. Muscle, frame, age, pregnancy and health conditions all matter. Talk to your doctor or a registered dietitian about a weight that is right for you.