UNDERSTAND THE METHOD
How to use this calculator
Use the same unit system for waist and height. Divide waist by height. Half your height gives the waist measurement at a ratio of 0.5.
What the result can tell you
This adult screening ratio does not measure body-fat percentage or distinguish visceral from subcutaneous fat. It does not diagnose underweight, obesity, or disease. Do not use these adult comparisons for children or pregnancy.
Waist-to-height ratio by height, including the military limit
Waist-to-height ratio is your waist divided by your height, in the same unit. Half your height is the waist at a ratio of 0.5, the general screening reference this calculator compares against.
Waist at a 0.5 ratio by height
| Height | Waist at 0.5 (in) | Waist at 0.5 (cm) |
|---|---|---|
| 4 ft 10 in | 29.0 in | 73.7 cm |
| 5 ft 0 in | 30.0 in | 76.2 cm |
| 5 ft 2 in | 31.0 in | 78.7 cm |
| 5 ft 4 in | 32.0 in | 81.3 cm |
| 5 ft 6 in | 33.0 in | 83.8 cm |
| 5 ft 8 in | 34.0 in | 86.4 cm |
| 5 ft 10 in | 35.0 in | 88.9 cm |
| 6 ft 0 in | 36.0 in | 91.4 cm |
| 6 ft 2 in | 37.0 in | 94.0 cm |
| 6 ft 4 in | 38.0 in | 96.5 cm |
| 6 ft 6 in | 39.0 in | 99.1 cm |
| 6 ft 8 in | 40.0 in | 101.6 cm |
The US military uses a different line. Under Department of War Instruction 1308.03 (August 31, 2026), a waist-to-height ratio below 0.55 meets the upper limit, and height and waist are recorded in inches rounded down to the nearest half inch. The next table lists, for each recorded height, the largest recorded waist that stays below 0.55 and the first half inch that does not.
Largest recorded waist below 0.55, by recorded height
| Recorded height | Largest waist below 0.55 | Ratio | First waist at 0.55 or above |
|---|---|---|---|
| 4 ft 10 in (58 in) | 31.5 in | 0.543 | 32.0 in (0.551) |
| 4 ft 11 in (59 in) | 32.0 in | 0.542 | 32.5 in (0.550) |
| 5 ft 0 in (60 in) | 32.5 in | 0.541 | 33.0 in (0.550) |
| 5 ft 1 in (61 in) | 33.5 in | 0.549 | 34.0 in (0.557) |
| 5 ft 2 in (62 in) | 34.0 in | 0.548 | 34.5 in (0.556) |
| 5 ft 3 in (63 in) | 34.5 in | 0.547 | 35.0 in (0.555) |
| 5 ft 4 in (64 in) | 35.0 in | 0.546 | 35.5 in (0.554) |
| 5 ft 5 in (65 in) | 35.5 in | 0.546 | 36.0 in (0.553) |
| 5 ft 6 in (66 in) | 36.0 in | 0.545 | 36.5 in (0.553) |
| 5 ft 7 in (67 in) | 36.5 in | 0.544 | 37.0 in (0.552) |
| 5 ft 8 in (68 in) | 37.0 in | 0.544 | 37.5 in (0.551) |
| 5 ft 9 in (69 in) | 37.5 in | 0.543 | 38.0 in (0.550) |
| 5 ft 10 in (70 in) | 38.0 in | 0.542 | 38.5 in (0.550) |
| 5 ft 11 in (71 in) | 39.0 in | 0.549 | 39.5 in (0.556) |
| 6 ft 0 in (72 in) | 39.5 in | 0.548 | 40.0 in (0.555) |
| 6 ft 1 in (73 in) | 40.0 in | 0.547 | 40.5 in (0.554) |
| 6 ft 2 in (74 in) | 40.5 in | 0.547 | 41.0 in (0.554) |
| 6 ft 3 in (75 in) | 41.0 in | 0.546 | 41.5 in (0.553) |
| 6 ft 4 in (76 in) | 41.5 in | 0.546 | 42.0 in (0.552) |
| 6 ft 5 in (77 in) | 42.0 in | 0.545 | 42.5 in (0.551) |
| 6 ft 6 in (78 in) | 42.5 in | 0.544 | 43.0 in (0.551) |
| 6 ft 7 in (79 in) | 43.0 in | 0.544 | 43.5 in (0.550) |
| 6 ft 8 in (80 in) | 43.5 in | 0.543 | 44.0 in (0.550) |
Worked example: you measure 70¼ in tall with a 38.9 in waist. The instruction records 70 in and 38.5 in, so the ratio is 38.5 ÷ 70 = 0.550, which is not below 0.55. At 70 in, the largest recorded waist below the limit is 38.0 in, so this waist is 0.5 in over. Rounding the height down raised the ratio; rounding the waist down lowered it.
The military table shows the Department of War upper limit only. Your service can set a lower ratio, and its trained measurers and its own instruction decide the official result. For a height on the half inch, use the military screen above.
Each service also publishes its own rules, and as of October 2026 they differ from the instruction and from each other. All five were issued before the instruction and may change to match it. The Marine Corps uses a lower limit, four services measure the waist at the navel, and the Army has no body fat step.
Waist-to-height rules by service, as published by October 2026
| Service and rule | Meets the standard | Waist measured at | Above the limit |
|---|---|---|---|
| Department of War, Instruction 1308.03 (Aug 31, 2026) | Below 0.55 (upper limit for all services) | Midpoint between the lowest rib and the top of the hip bone | Body fat calculation |
| Army, Directive 2026-13 (effective Jul 7, 2026) | Below 0.55 | Navel | Enrollment in the Army Body Composition Program; no tape test |
| Navy, Guide 4 (Jun 2026) | 0.5499 or below | Navel | Body fat estimate; limit 26% for men, 36% for women |
| Marine Corps, MARADMIN 066/26 and 073/26 (from Jan 1, 2026) | 0.52 or below; the MARADMIN table of largest waist by height decides | Navel | Body fat by multi-site tape or bioelectrical impedance |
| Air Force, AFMAN 36-2905 (Mar 24, 2026) | Not high risk at .55 or below, after the ratio is cut to two decimals | Midpoint between the lowest rib and the top of the hip bone | Body fat assessment only if the fitness assessment is also failed; below 26% men, 36% women |
| Space Force, SPFMAN 36-2905 (Change 3, Apr 24, 2026) | Below 0.55, after the ratio is cut to two decimals | Navel (paragraph 9.4.3.1; the manual's step-by-step instructions say the rib-to-hip-bone midpoint) | Body fat calculation; limit 26.0% for men, 36.0% for women |
Rounding differs too. The instruction and the Marine Corps round both height and waist down to the half inch. The Navy rounds the waist down but the height up to the half inch, which lowers the ratio. The Air Force rounds the waist down and records height to the nearest half inch. The Army records the ratio to three decimals and drops the rest. The screen above starts with the instruction's rules. Pick your service there to apply its own rounding, limit, waist site and, for the Marine Corps, the MARADMIN table of largest waist by height.
Common questions
How is the waist-to-height ratio calculated?
Use the same unit system for waist and height, then divide waist by height. Half your height is the waist measurement at a ratio of 0.5.
Can I use this adult screening reference for a child or pregnancy?
No. These are adult comparisons. They do not measure body fat or diagnose underweight, obesity, or disease, and they are not for children or pregnancy.
Does the military use waist-to-height ratio?
Yes. Department of War Instruction 1308.03 (August 31, 2026) makes waist-to-height the first body composition check for the Army, Navy, Marine Corps, Air Force and Space Force. The upper limit is a ratio below 0.55, and each service can set a lower one. The instruction records height and waist in inches rounded down to the nearest half inch, and at 0.55 or above, or above a service's lower limit, it calls for a body fat calculation. Service rules differ; see the next question. The military screen on this page applies the instruction, or a service's own rules when you pick one.
Does every military service use the same waist-to-height limit?
No. As of October 2026 the Army, Navy and Space Force require a ratio below 0.55, the Air Force rates a ratio above .55 as high risk after cutting it to two decimals, and the Marine Corps requires 0.52 or below. The Army, Navy, Marine Corps and Space Force measure the waist at the navel, the Navy rounds height up to the half inch, and the Army has no body fat step after a failed ratio. The table in the calculation reference on this page lists each service's rule with its source.
Sources & limitations16 sources
Sources checked September 12, 2026. These notes identify methods and assumptions. They have not received an independent clinical review.
- Review of waist-to-height ratio as an adult screening measure.pubmed.ncbi.nlm.nih.gov
- Evidence review of the 0.5 screening boundary.pubmed.ncbi.nlm.nih.gov
- DoW Instruction 1308.03 (August 31, 2026): body composition by waist-to-height ratio below 0.55, measured in inches rounded down to the nearest half inch, with a body fat calculation at 0.55 or above or above a lower service limit.esd.whs.mil
- Army Directive 2026-13: standard is a waist-to-height ratio below 0.55; 0.55 or greater means enrollment in the Army Body Composition Program.home.army.mil
- Army ABCP FAQ (effective July 7, 2026): waist at the navel, ratio recorded to three decimals, tape test rescinded.army.mil
- Navy Guide 4 (June 2026): height rounded up and navel waist rounded down to the half inch; 0.5500 or more goes to a body fat estimate (26% men, 36% women).mynavyhr.navy.mil
- MARADMIN 066/26: waist at the navel and height rounded down to the half inch, with a maximum-waist table by height.marines.mil
- MARADMIN 073/26 (February 27, 2026): the Marine Corps waist-to-height standard is less than or equal to 0.52, regardless of sex.marines.mil
- AFMAN 36-2905 (March 24, 2026): waist at the rib-to-hip-bone midpoint, ratio cut to two decimals; above .55 with an unmet fitness assessment needs a body fat assessment.static.e-publishing.af.mil
- SPFMAN 36-2905 (Change 3, April 24, 2026): Space Force standard below 0.55, ratio cut to two decimals, body fat calculation at 0.55 or above (26.0% men, 36.0% women).static.e-publishing.af.mil
- CDC adult BMI categories apply from age 20.cdc.gov
- WHO reviews waist and hip measurement methods and adult screening thresholds.who.int
- Krakauer and Krakauer define ABSI and publish population study comparisons.journals.plos.org
- Original Table S1 provides age- and sex-specific reference means and standard deviations.journals.plos.org
- Thomas and colleagues introduced the geometric body roundness index using height and waist circumference in adult research samples.onlinelibrary.wiley.com
- The BRI equation uses 364.2 − 365.5 × √(1 − (waist ÷ (π × height))²), with matching length units.nature.com