BMI, Category, and Code — in One Step.
A BMI is only useful on a claim when it’s paired with the right code and a documented condition. Enter height and weight to get the BMI, the CDC category, the matching ICD-10-CM Z68 code, and a quick check against MIPS Quality Measure #128.
- Imperial or metric, calculated to one decimal
- The exact Z68 code for adults, and pediatric guidance
- Healthy weight range for the patient’s height
Runs entirely in your browser — nothing you enter is stored or sent anywhere.
Height and weight
Units
Patient aged 20 or over?
Body mass index
28.9
Overweight
ICD-10-CM code
Z68.28
BMI 28.0–28.9, adult
Z68 codes are secondary codes. Report them only alongside an associated, documented condition — such as obesity, overweight, or underweight — that the provider has addressed.
Healthy range for this height
125 lb – 169 lb
BMI 18.5–24.9
MIPS Measure #128
Follow-up plan needed
Adults 18+: normal is ≥18.5 and <25
BMI is a screening measure, not a diagnosis. It doesn’t distinguish muscle from fat and is interpreted differently for children, older adults, and some populations. Clinical judgment always applies.
How It Works
Coding BMI Correctly
BMI codes (Z68) are supplementary. Under the ICD-10-CM Official Guidelines they should only be reported when there is an associated, reportable diagnosis — obesity, overweight, underweight, or another condition the provider addresses. BMI may be documented by clinicians other than the provider, but the associated diagnosis must come from the provider.
The formula
BMI = weight (kg) ÷ height (m)² · imperial: 703 × weight (lb) ÷ height (in)²
Adults 20+
Z68.1 – Z68.45
One code per BMI band: Z68.1 for 19.9 or less, Z68.20–Z68.39 for each whole number from 20 to 39, then Z68.41–Z68.45 for 40 and above.
Ages 2–19
Percentiles, not BMI values
Pediatric codes Z68.51–Z68.56 are based on BMI-for-age percentile. Z68.55 and Z68.56 were added in FY2025 for severe obesity (120% and 140% of the 95th percentile).
MIPS #128
Screening plus a plan
Quality Measure #128 credits a documented BMI and, when it is outside normal parameters (adults: 18.5 to under 25), a documented follow-up plan.
Adult BMI categories (CDC) and Z68 codes
| BMI | CDC category | ICD-10-CM |
|---|---|---|
| Under 18.5 | Underweight | Z68.1 (19.9 or less) |
| 18.5 – 24.9 | Healthy weight | Z68.1 / Z68.20–Z68.24 |
| 25.0 – 29.9 | Overweight | Z68.25–Z68.29 |
| 30.0 – 34.9 | Obesity, class 1 | Z68.30–Z68.34 |
| 35.0 – 39.9 | Obesity, class 2 | Z68.35–Z68.39 |
| 40.0 and over | Obesity, class 3 (severe) | Z68.41–Z68.45 |
Questions
Frequently Asked Questions
Can I report a Z68 code on its own?
No. BMI codes should only be assigned with an associated, reportable diagnosis the provider documents — for example obesity (E66.x), overweight, or underweight. A BMI by itself isn’t a reportable condition.
Who can document BMI?
BMI can be taken from documentation by other clinicians, such as a nurse or dietitian. The associated diagnosis (for example, obesity) must be documented by the provider.
Which code do I use for a BMI of exactly 40.0?
Z68.41 (BMI 40.0–44.9, adult). This calculator rounds BMI to one decimal before selecting the code.
Do adult BMI codes apply to an 18-year-old?
Adult Z68 codes are for patients aged 20 and over. For ages 2–19, use the percentile-based pediatric codes from CDC growth charts.
How does BMI relate to MIPS?
Quality Measure #128 (Preventive Care and Screening: BMI Screening and Follow-Up Plan) requires a documented BMI and, if it’s outside normal parameters, a follow-up plan. It’s one of the most commonly reported primary care measures.
Is BMI accurate for every patient?
No. It doesn’t distinguish muscle from fat and is interpreted differently for older adults, athletes, and some populations. It’s a screening tool — clinical judgment comes first.
Sources
- [1]CDC — Adult BMI categories
- [2]CDC — ICD-10-CM codes for adult and childhood obesity (2024)
- [3]CMS — ICD-10-CM Official Guidelines for Coding and Reporting
This is an independent planning tool built by MedVersify from published methodology. It is not an official CMS, payer, or clinical tool, and results are estimates — confirm decisions against your own reports, payer contracts, and clinical judgment.
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