BMI category cut-offs by height: weight ranges in kg and lb

BMI category cut-offs by height: weight ranges in kg and lb

BMI is weight in kilograms divided by height in metres squared. At 170 cm, the Normal range (BMI 18.5 to under 25) is 53.46 kg up to just under 72.25 kg, and at 5'8" it is 121.68 lb up to just under 164.44 lb. The tables below convert every cut-off into a weight for common heights.

Informational only, not medical advice. BMI is a screening number and does not measure body fat, muscle, age, sex or health. Talk to a clinician about your own situation.

What are the BMI cut-offs?

The cut-offs used by Mathify's BMI Calculator are:

• Under 16: Severe Thinness
• 16 to under 17: Moderate Thinness
• 17 to under 18.5: Mild Thinness
• 18.5 to under 25: Normal
• 25 to under 30: Overweight
• 30 to under 35: Obese Class I
• 35 to under 40: Obese Class II
• 40 and over: Obese Class III

Each lower bound is included in its category and the upper bound is not. This page does not attribute the cut-offs to any organization because the calculator's code does not cite one.

How do you turn a BMI cut-off into a weight?

Rearrange the formula. In metric units, weight (kg) = BMI x height (m)^2. In imperial units, weight (lb) = BMI x height (in)^2 / 703. Every boundary in the tables was verified by running the BMI calculator code on a weight just below and just above it, and confirming the category changes. The generating script is scripts/content-data/bmi-cutoffs-by-height.ts.

What weight ranges apply at each height in kg?

Assumptions: adult BMI formula, height in cm, weights in kg rounded to two decimals. Each row lists the weight at which the category ends, so "Overweight up to under 86.70 kg" means Overweight runs from the Normal upper limit to just below 86.7 kg.

• 150 cm: Normal 41.63 to under 56.25 kg | Overweight up to under 67.50 kg | Obese Class I up to under 78.75 kg | Class II up to under 90.00 kg
• 155 cm: Normal 44.45 to under 60.06 kg | Overweight up to under 72.08 kg | Obese Class I up to under 84.09 kg | Class II up to under 96.10 kg
• 160 cm: Normal 47.36 to under 64.00 kg | Overweight up to under 76.80 kg | Obese Class I up to under 89.60 kg | Class II up to under 102.40 kg
• 165 cm: Normal 50.37 to under 68.06 kg | Overweight up to under 81.67 kg | Obese Class I up to under 95.29 kg | Class II up to under 108.90 kg
• 170 cm: Normal 53.46 to under 72.25 kg | Overweight up to under 86.70 kg | Obese Class I up to under 101.15 kg | Class II up to under 115.60 kg
• 175 cm: Normal 56.66 to under 76.56 kg | Overweight up to under 91.88 kg | Obese Class I up to under 107.19 kg | Class II up to under 122.50 kg
• 180 cm: Normal 59.94 to under 81.00 kg | Overweight up to under 97.20 kg | Obese Class I up to under 113.40 kg | Class II up to under 129.60 kg
• 185 cm: Normal 63.32 to under 85.56 kg | Overweight up to under 102.68 kg | Obese Class I up to under 119.79 kg | Class II up to under 136.90 kg
• 190 cm: Normal 66.78 to under 90.25 kg | Overweight up to under 108.30 kg | Obese Class I up to under 126.35 kg | Class II up to under 144.40 kg
• 195 cm: Normal 70.35 to under 95.06 kg | Overweight up to under 114.07 kg | Obese Class I up to under 133.09 kg | Class II up to under 152.10 kg

What weight ranges apply at each height in lb?

Assumptions: same cut-offs, height in inches (shown with feet and inches), weights in pounds rounded to two decimals.

• 4'10" (58 in): Normal 88.53 to under 119.63 lb | Overweight up to under 143.56 lb | Obese Class I up to under 167.48 lb | Class II up to under 191.41 lb
• 5'0" (60 in): Normal 94.74 to under 128.02 lb | Overweight up to under 153.63 lb | Obese Class I up to under 179.23 lb | Class II up to under 204.84 lb
• 5'2" (62 in): Normal 101.16 to under 136.70 lb | Overweight up to under 164.04 lb | Obese Class I up to under 191.38 lb | Class II up to under 218.72 lb
• 5'4" (64 in): Normal 107.79 to under 145.66 lb | Overweight up to under 174.79 lb | Obese Class I up to under 203.93 lb | Class II up to under 233.06 lb
• 5'6" (66 in): Normal 114.63 to under 154.91 lb | Overweight up to under 185.89 lb | Obese Class I up to under 216.87 lb | Class II up to under 247.85 lb
• 5'8" (68 in): Normal 121.68 to under 164.44 lb | Overweight up to under 197.33 lb | Obese Class I up to under 230.21 lb | Class II up to under 263.10 lb
• 5'10" (70 in): Normal 128.95 to under 174.25 lb | Overweight up to under 209.10 lb | Obese Class I up to under 243.95 lb | Class II up to under 278.81 lb
• 6'0" (72 in): Normal 136.42 to under 184.35 lb | Overweight up to under 221.22 lb | Obese Class I up to under 258.09 lb | Class II up to under 294.96 lb
• 6'2" (74 in): Normal 144.11 to under 194.74 lb | Overweight up to under 233.68 lb | Obese Class I up to under 272.63 lb | Class II up to under 311.58 lb
• 6'4" (76 in): Normal 152.00 to under 205.41 lb | Overweight up to under 246.49 lb | Obese Class I up to under 287.57 lb | Class II up to under 328.65 lb

Worked example: 70 kg at 170 cm

• BMI = 70 / (1.70 x 1.70) = 70 / 2.89 = 24.2, which is Normal.
• The Normal range at 170 cm is 53.46 kg to just under 72.25 kg.
• At the lower categories, BMI 16 = 46.24 kg, BMI 17 = 49.13 kg, BMI 18.5 = 53.46 kg at 170 cm.

A second case: 160 lb at 5'8" (68 in) gives BMI = 160 / 68^2 x 703 = 24.3, which is Normal. The Normal range at that height is 121.68 lb to just under 164.44 lb. As a cross-check, 160 lb is 72.6 kg and 68 in is 172.7 cm, which lands on the same category in metric.

For a higher weight, 90 kg at 170 cm gives BMI 31.1, which is Obese Class I. The gap between 90 kg and the top of the Normal range at 170 cm is about 17.8 kg.

How much does height change the numbers?

The weight bands move quickly with height because height is squared. Between 170 cm and 175 cm the upper Normal limit rises by about 4.3 kg. That is why the same weight can fall in different categories for two adults who are only a few centimetres apart.

What can BMI not tell you?

BMI uses only height and weight. It does not separate muscle from fat, and it does not reflect where fat is carried or any health measurement. Other Mathify tools look at different angles, such as the Ideal Weight Calculator and the Body Fat Calculator. For energy needs, see the BMR Calculator.

Common mistakes

• Mixing units, such as entering pounds with centimetres.
• Entering height in feet as a decimal (5.8) when it means 5 feet 8 inches.
• Reading the upper bound as part of the category; 25 itself is Overweight.
• Treating BMI as a diagnosis rather than a screening number.
• Using adult cut-offs for children, where different methods apply.

Key takeaways

• Weight at a BMI cut-off equals BMI x height squared (metric).
• Use the kg or lb table above to find the Normal range for your height.
• A few centimetres of height shifts the range by several kilograms.
• BMI is one measure and should be read with other information.

FAQ

What is a healthy weight for 170 cm?

By BMI, the Normal range at 170 cm is 53.46 kg to just under 72.25 kg. BMI is a screening tool, not a verdict on health.

What is the BMI range for Normal weight?

18.5 up to, but not including, 25.

How do I calculate BMI in pounds and inches?

Multiply weight in pounds by 703 and divide by height in inches squared.

Is 25 Normal or Overweight?

Overweight. The Normal category ends just below 25.

Do these tables work for children?

No. They apply the adult formula and cut-offs used by the calculator. Children's assessments use different methods.