| Factor | BMI | Body Fat Percentage |
|---|---|---|
| Measurement | Height and weight only | Fat mass vs lean mass |
| Equipment needed | None | Calipers, scale or DEXA |
| Accuracy | Limited (no body comp) | High (with DEXA/hydrostatic) |
| Athletes | Often misclassifies | Accurate for all body types |
| Health correlation | Moderate | Strong |
| Cost | Free | Varies (free to £200+) |
| Ease | Immediate | Requires measurement method |
Choose BMI when…
A quick initial health screening with no equipment, broad population-level assessment, or a simple first check without specialist measurement.
Choose Body Fat Percentage when…
You want an accurate picture of your actual body composition, are an athlete or muscular individual (BMI may incorrectly classify as overweight), want to track fat loss vs muscle gain specifically.
Gear for both
Body Composition Scale (BIA)
Measure body fat %, muscle mass and more at home.
Check price on AmazonSkinfold Caliper
Simple, affordable body fat measurement tool used by coaches worldwide.
Check price on AmazonAs an Amazon Associate we earn from qualifying purchases.
FAQ
Is BMI useful at all?
Yes, as a population-level screening tool — it's free, requires no measurement equipment and strongly correlates with health risk across large populations. Its weakness is individuals who are muscular (often 'overweight' on BMI despite low body fat) or who carry fat internally with a normal BMI.
What body fat % is healthy?
For men, 10-20% is generally healthy; athletes are often 6-13%; above 25% indicates excess fat. For women, 18-28% is healthy; female athletes 14-20%; above 32% indicates excess fat. These ranges vary by source and individual factors.
How do I measure body fat percentage at home?
Practical home methods: skinfold calipers (require technique, moderate accuracy ±3–4%); bioelectrical impedance scales (convenient but affected by hydration, ±3–4%); DEXA scan (gold standard, requires a clinic visit, ±1–2%). For most people, tracking trends over time using consistent methods is more useful than obsessing over a precise number — any single measurement has inherent error.