Fitness and Body Calculators
Body fat percentage estimate from tape measurements (US Navy method) with fat mass, lean mass and a general category.
OtherLiveeip155:8453Exactvia cdp
Body-fatHealthCalculator
Calls · 30d
1
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 4 snapshots so far.
$24.31
Verified settled volume
1,175 settlements proven x402 by their on-chain EIP-3009 marker.
$0.020
Listed price
As published in the catalog. Always read the live 402 before paying.
1
Calls · 30d
Upstream's own call count for this endpoint, not ours.
1
Unique payers · 30d
Last called 2026-10-20 20:46Z
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0xb531320805C5BED1D46AEaDcF4F008FDF172DBDaThe wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.
Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
Provider
The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.
Live 402 challenge
Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.
{
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"payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
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"mimeType": "application/json",
"resource": "https://fitness-calc.x402tookit.com/body-fat-navy",
"description": "Body fat percentage estimate from tape measurements (US Navy method) with fat mass, lean mass and a general category.",
"outputSchema": {
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"asOf": "2026-10-11T08:36:49.562Z",
"source": "computed locally",
"reasons": [
"US Navy circumference method (inches, base-10 logs). Accuracy is about 3 to 4 points against DEXA.",
"Categories are the American Council on Exercise ranges."
],
"summary": "Estimated body fat 17.5% (Average).",
"verdict": "AVERAGE",
"category": "Average",
"degraded": false,
"fatMassKg": null,
"bodyFatPct": 17.51,
"disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
"leanMassKg": null,
"notChecked": [
"measurement technique (a 1 cm error moves the result 1 to 2 points)",
"anything but a rough estimate: the Navy method is accurate to about 3 to 4 points against DEXA and is poor at very low or high body fat and for very muscular people",
"…2 more"
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"description": "Body fat percentage estimate from tape measurements (US Navy method) with fat mass, lean mass and a general category.",
"outputSchema": {
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"source": "computed locally",
"reasons": [
"US Navy circumference method (inches, base-10 logs). Accuracy is about 3 to 4 points against DEXA.",
"Categories are the American Council on Exercise ranges."
],
"summary": "Estimated body fat 17.5% (Average).",
"verdict": "AVERAGE",
"category": "Average",
"degraded": false,
"fatMassKg": null,
"bodyFatPct": 17.51,
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"leanMassKg": null,
"notChecked": [
"measurement technique (a 1 cm error moves the result 1 to 2 points)",
"anything but a rough estimate: the Navy method is accurate to about 3 to 4 points against DEXA and is poor at very low or high body fat and for very muscular people",
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"description": "Body fat percentage estimate from tape measurements (US Navy method) with fat mass, lean mass and a general category.",
"outputSchema": {
"input": {
"type": "http",
"method": "GET",
"queryParams": {
"sex": "male",
"neck": 15,
"units": "imperial",
"waist": 34,
"height": 70
}
},
"output": {
"sex": "male",
"asOf": "2026-10-11T08:36:49.562Z",
"source": "computed locally",
"reasons": [
"US Navy circumference method (inches, base-10 logs). Accuracy is about 3 to 4 points against DEXA.",
"Categories are the American Council on Exercise ranges."
],
"summary": "Estimated body fat 17.5% (Average).",
"verdict": "AVERAGE",
"category": "Average",
"degraded": false,
"fatMassKg": null,
"bodyFatPct": 17.51,
"disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
"leanMassKg": null,
"notChecked": [
"measurement technique (a 1 cm error moves the result 1 to 2 points)",
"anything but a rough estimate: the Navy method is accurate to about 3 to 4 points against DEXA and is poor at very low or high body fat and for very muscular people",
"…2 more"
],
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}
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"x402Version": 1,
"alsoAvailable": {
"llms": "https://fitness-calc.x402tookit.com/llms.txt",
"catalog": "https://fitness-calc.x402tookit.com/catalog",
"message": "Fitness and Body Calculators has 10 pay-per-call endpoints (BMI, ideal weight, calorie needs, macros, one-rep max, heart-rate zones, race pace and prediction, body fat, calorie burn, due date.), from $0.02 a call. See the full menu and send your agents our way.",
"openapi": "https://fitness-calc.x402tookit.com/openapi.json",
"related": [
{
"url": "https://fitness-calc.x402tookit.com/ideal-weight",
"path": "/ideal-weight",
"what": "Ideal body weight by the Devine, Robinson, Miller and Hamwi formulas from height and sex,…",
"price": "$0.02"
},
{
"url": "https://fitness-calc.x402tookit.com/bmi",
"path": "/bmi",
"what": "Body mass index from weight and height, metric or imperial, with the WHO adult category a…",
"price": "$0.02"
},
{
"url": "https://fitness-calc.x402tookit.com/calorie-burn",
"path": "/calorie-burn",
"what": "Calories burned by an activity (walking, running, cycling, swimming and more) from MET va…",
"price": "$0.02"
}
]
}
}Accepts
The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.
0.02USDC≈ $0.02 USD
on Base · exact scheme
Pay 0.02 USDC on Base to 0xb531…2DBDa. The signed payment is good for 5 minutes.
- Paid to
- 0xb531…2DBDa
- USD Coin contract
- 0x8335…02913
- Payment window
- 5 minutes
- As published
- 20000 smallest units
20000units
on solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp · exact scheme
That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.
- Paid to
- DUPiup…eEm8s
- Token contract
- EPjFWd…TDt1v
- Payment window
- 5 minutes
20000units
on Polygon · exact scheme
That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.
- Paid to
- 0xb531…2DBDa
- Token contract
- 0x3c49…c3359
- Payment window
- 5 minutes
20000units
on Arbitrum · exact scheme
That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.
- Paid to
- 0xb531…2DBDa
- Token contract
- 0xaf88…e5831
- Payment window
- 5 minutes
The catalog’s raw entry
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"scheme": "exact",
"network": "eip155:8453",
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{
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"info": {
"input": {
"type": "http",
"method": "GET",
"queryParams": {
"sex": "male",
"neck": 15,
"units": "imperial",
"waist": 34,
"height": 70
}
},
"output": {
"type": "json",
"example": {
"sex": "male",
"asOf": "2026-10-11T08:36:49.562Z",
"source": "computed locally",
"reasons": [
"US Navy circumference method (inches, base-10 logs). Accuracy is about 3 to 4 points against DEXA.",
"Categories are the American Council on Exercise ranges."
],
"summary": "Estimated body fat 17.5% (Average).",
"verdict": "AVERAGE",
"category": "Average",
"degraded": false,
"fatMassKg": null,
"bodyFatPct": 17.51,
"disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
"leanMassKg": null,
"notChecked": [
"measurement technique (a 1 cm error moves the result 1 to 2 points)",
"anything but a rough estimate: the Navy method is accurate to about 3 to 4 points against DEXA and is poor at very low or high body fat and for very muscular people",
"…2 more"
],
"inputsInches": {
"hip": null,
"neck": 15,
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"properties": {
"hip": {
"type": "number",
"description": "Hip at the widest point (required for women)"
},
"sex": {
"type": "string",
"description": "male or female"
},
"neck": {
"type": "number",
"description": "Neck circumference below the larynx"
},
"units": {
"type": "string",
"description": "metric (cm, kg; default) or imperial (inches, lb)"
},
"waist": {
"type": "number",
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},
"height": {
"type": "number",
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"weight": {
"type": "number",
"description": "Body weight to also give fat and lean mass"
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}
}Provenance
- Seen in the source catalog
- 2026-10-20 20:46Z
- Last indexed by Roundhouse
- 2026-10-22 12:40Z
- Last enriched (probe, favicon, geo)
- 2026-10-20 22:45Z
- x402 version
- 2
- Max timeout
- 300s
- Liveness probe
- HTTP 402
Hand this page to an agent
Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.
GET api.roundhouseai.io/v0/endpoints
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 4 snapshots so far. Verified volume counts only settlements with an on-chain EIP-3009 marker.
Show the promptHide the prompt
Using Roundhouse, look up the x402 service Fitness and Body Calculators and tell me whether it is worth paying: what a call costs, whether the endpoint answered when last probed, and what its payment record actually shows. curl -s 'https://api.roundhouseai.io/v0/endpoints?q=Fitness%20and%20Body%20Calculators' curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>' Then call it: read the price from the live 402 at https://fitness-calc.x402tookit.com/body-fat-navy, never from a cached figure, and pay with an x402 client. The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except /v0/unified* and /v0/endpoints. Either pay over x402 (mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402), or ask me for an organization key, which I create at https://roundhouseai.io/dashboard/connections. If you have neither, ask before going further. If you do not have Roundhouse tools or skills installed, read https://roundhouseai.io/skill.md first — it is the whole procedure.