TL;DR
- DEXA is the more accurate body-composition method; InBody is precise (consistent) but carries a systematic offset against DEXA, so use InBody to track change and DEXA when you need an absolute number.
- DEXA is a reference method validated against the 4-compartment model, with body-fat precision often cited around 1 to 2 percentage points under standardized conditions.[1]
- InBody multi-frequency BIA correlates strongly with DEXA (often r ≥ 0.95) but Bland-Altman analysis shows statistically significant mean bias and wide limits of agreement for individuals.[2][3]
- InBody is often free or low-cost at gyms; a DEXA body-composition scan typically runs about $40 to $200 in 2026.[5]
When you need a trustworthy absolute body-fat number, DEXA is the better tool; when you want a frequent, cheap, repeatable read to watch a trend, InBody is the practical choice. InBody is highly precise but offset from DEXA, which makes it excellent for tracking change and unreliable for one-time absolute classification. This compares verified accuracy data, cost, and where each method belongs.
Verified comparison
| Dimension | DEXA | InBody (multi-frequency BIA) |
|---|---|---|
| Method class | Reference method, validated vs 4-compartment model[1] | Multi-frequency bioelectrical impedance[4] |
| Body-fat precision | ~1 to 2 percentage points under standardized conditions[1] | High precision (repeatable) but systematic offset vs DEXA[3] |
| Agreement with DEXA | n/a (criterion) | Strong correlation (often r ≥ 0.95) but significant mean bias, wide limits of agreement[2] |
| Hydration sensitivity | Low; ~5% hydration shift alters DEXA fat by ~3%[1] | High; BIA depends directly on body water[4] |
| Typical cost (2026) | ~$40 to $200 per body-comp scan[5] | Often free or low-cost at gyms[5] |
| Best for | Absolute body-fat and segmental lean/fat reference | Frequent, cheap trend tracking |
What DEXA's accuracy actually is
DEXA is treated as a reference method because it validates well against the four-compartment model (fat, water, bone mineral, residual), with body-fat precision frequently cited around 1 to 2 percentage points under standardized conditions.[1] It is not flawless: studies report mean differences against criterion methods in the 2 to 4 percentage-point range depending on population, and individual error can be larger than the mean error suggests.[1] Even DEXA is sensitive to hydration — a 5% shift in hydration status can move its body-fat estimate by roughly 3 percentage points — so consistent measurement conditions matter even for the reference method.[1]
What InBody gets right and wrong
InBody's strength is precision: repeated scans on the same person under the same conditions are highly consistent, which is exactly what you want for tracking change. A comparison of four InBody devices against DXA found high correlations (often r ≥ 0.95) for muscle and fat mass — but Bland-Altman analysis revealed statistically significant mean biases and wide limits of agreement across all four devices.[2] A separate study summarized the pattern bluntly: standing BIA shows high precision but a systematic offset compared with DXA.[3]
The "wide limits of agreement" point is the one that matters for an individual. A strong group correlation can still mean a single person's InBody body-fat reading sits several percentage points away from their true DEXA value. Because InBody infers composition from body water and uses population assumptions about hydration, it can over- or under-estimate fat-free mass when an individual's hydration or body geometry deviates from those assumptions.[4]
The cost difference and what it buys
InBody scans are often free or low-cost as part of a gym membership or training consultation, which is the practical reason they are everywhere.[5] A DEXA body-composition scan typically costs about $40 to $200 in 2026 at wellness clinics, with mobile providers often in the $65 to $150 range.[5] The cost gap maps directly to the use case: InBody's near-zero marginal cost makes frequent re-testing realistic (which suits trend tracking), while DEXA's per-scan cost makes it a periodic checkpoint for an absolute number.
Decision guidance
- You need a trustworthy absolute body-fat figure: DEXA — it is the reference method.[1]
- You want to track change every few weeks cheaply: InBody — precise enough for a trend, and often free at gyms.[2][5]
- You will use both: Anchor with a DEXA, then track with InBody between scans, holding measurement conditions constant.[3]
- You only have InBody access: Always measure under the same hydration and time-of-day conditions and read the trend, not the absolute.[4]
For how these clinical and gym methods compare with home options, see DEXA vs smart-scale body fat and the caliper vs BIA vs DEXA accuracy breakdown. To turn a measured body fat into a fuller composition picture, the Body Fat Percentage Calculator cross-checks circumference methods against your scan result.
Accuracy figures and cost ranges verified as of 2026-05-25 against the cited validation studies and 2026 scan-pricing sources. Per-scan prices vary by provider and region.
FAQ
Is InBody as accurate as DEXA?
No. InBody correlates strongly with DEXA at the group level but shows a systematic offset and wide limits of agreement for individuals, so it is precise for tracking change but not a substitute for DEXA's absolute accuracy.[2][3]
Why does InBody disagree with DEXA on a given day?
InBody infers composition from body water and population hydration assumptions, so individual hydration, food intake, and body geometry shift its reading away from the DEXA value.[4]
How much does each cost in 2026?
InBody is often free or low-cost at gyms; a DEXA body-composition scan typically runs about $40 to $200, with mobile providers often $65 to $150.[5]
Which should I use for a cut?
InBody for frequent trend checks during the cut, ideally bookended by a DEXA at the start and end for accurate absolute numbers — measuring InBody under identical conditions each time.[3]
References
- 1 DEXA scans: precision, validity against the 4-compartment model — Science for Sport (2024)
- 2 Comparison of four InBody devices and DXA: high correlation, significant mean bias and wide limits of agreement — Korean Journal of Health Promotion (2023)
- 3 High precision but systematic offset in standing BIA compared with DXA — Scientific Reports (2023)
- 4 Reliability, biological variability, and accuracy of multi-frequency BIA for body composition — Frontiers in Nutrition (2024)
- 5 DEXA Scan Cost: 2026 pricing breakdown — Primary MD (2026)