Rockport one-mile walk VO2 max calculator
A 40-year-old man weighing 70 kg who walks a mile in 15:30 and finishes with a heart rate of 140 has an estimated VO2 max of 39.2766 mL/kg/min. Enter time, heart rate, weight, age and sex to gauge fitness without running. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Time min
- 15.5
- Heart rate
- 140
- Weight
- 70
- Weight unit
- Kg
- Age
- 40
- Sex
- male
- Vo2max ml kg min
- 39.2766
- Time display
- 15:30
- Weight lb
- 154.3236
- Weight (kg)
- 70
This Rockport walk test VO2 max calculator estimates maximal oxygen uptake in millilitres per kilogram per minute from a timed one-mile walk, the heart rate measured at the finish, body weight, age, and sex. The Rockport Fitness Walking Test is a classic submaximal field protocol used in fitness labs, coaching, and workplace wellness when a full graded treadmill test is impractical. The engine applies the published Kline and colleagues regression with fixed coefficients, converts weight between kilograms and pounds when needed, and returns a deterministic estimate plus the normalised inputs. Small reference checks include a middle-aged adult walking the mile in about fifteen minutes with a moderate recovery pulse, which should land in a plausible mid-thirties to forties range of millilitres per kilogram per minute depending on sex and body mass. There is no network call, no random sampling, and no dependence on the current date.
What your Rockport estimate tells you
VO2 max is the standard laboratory measure of cardiorespiratory fitness: the highest rate at which the body can take up and use oxygen during intense exercise, usually expressed relative to body mass as millilitres per kilogram per minute. Direct measurement needs a metabolic cart and a maximal effort, so field tests estimate the same quantity from easier submaximal work.
The Rockport one-mile walk asks the participant to walk one mile as quickly as is comfortable without running, then records the finish time and the immediate post-walk heart rate together with age, sex, and body weight. Those five inputs enter a multiple linear regression published by Kline and co-authors that maps slower times, higher recovery rates, greater age, and greater weight toward lower estimated VO2 max, with a positive offset for male sex in the original coding. The path is fully deterministic: identical inputs always produce the same rounded output.
Values above the documented soft ceilings for age, weight, walk time, and heart rate are also refused so a typo cannot produce a meaningless estimate. The tool does not prescribe training zones, medical clearance, or diagnosis; it only evaluates the published Rockport equation on the numbers you supply.
Where the Rockport walk test fits in coaching, education, and software
Coaches and personal trainers use the one-mile walk when clients cannot or should not run a maximal shuttle or treadmill protocol, yet still want a numeric fitness baseline that can be retested after a training block. Teachers and exercise physiology courses assign the Rockport walk as a laboratory that students can complete on a measured track, then plug time and recovery heart rate into the regression to see how body mass and age shift the estimate.
Workplace wellness and insurance-adjacent programmes sometimes prefer a walk-based field test because it is low skill and low impact compared with a one-and-a-half-mile run. Developers call the same contract from scripts to seed deterministic test vectors for fitness apps, to normalise coach-entered logs before charting, or to satisfy programming exercises that demand a documented VO2 max formula rather than a hand-waved chart lookup.
Pair it with pace or heart-rate helpers when you build a small lab of free, deterministic health calculators, and always treat the number as an estimate from a submaximal walk, not a clinical diagnosis.
What you can do with it
Baseline fitness tracking
Estimate VO2 max after a timed one-mile walk and retest monthly to track aerobic gains without a lab cart.
Exercise physiology labs
Generate reproducible Rockport results for student worksheets, answer keys, and classroom demos from measured time and heart rate.
FAQ
What does the Rockport VO2 max calculator cost?
It is free in your browser on this page.
What happens if time, heart rate, weight, or age is zero or negative?
Non-positive values are not valid for the Rockport estimate.
Is this a medical diagnosis of cardiorespiratory fitness?
No. It is a deterministic field-test estimate from published coefficients. It does not replace graded exercise testing or clinical advice.
What VO2 max does a 15:30 Rockport walk give?
For a 40-year-old man weighing 70 kg whose heart rate is 140 at the finish, the estimate is 39.2766 mL/kg/min. A different heart rate, age, weight or sex shifts the result.
How do I do the Rockport walk test?
Walk one mile on a measured course as quickly as is comfortable without running. Note your finish time and your heart rate right at the end, then enter them with your age, sex and body weight.
Related tools
For developers — API access
Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.
API endpoint
Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.
Call it from your stack
curl -X POST https://api.kit.forhosting.com/health/vo2max-rockport \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"heart_rate":140,"weight":70,"age":40,"sex":"male","time_min":15.5}'const res = await fetch("https://api.kit.forhosting.com/health/vo2max-rockport", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"heart_rate": 140,
"weight": 70,
"age": 40,
"sex": "male",
"time_min": 15.5
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/health/vo2max-rockport",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"heart_rate": 140,
"weight": 70,
"age": 40,
"sex": "male",
"time_min": 15.5
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/health/vo2max-rockport", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"heart_rate":140,"weight":70,"age":40,"sex":"male","time_min":15.5}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"heart_rate":140,"weight":70,"age":40,"sex":"male","time_min":15.5}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/health/vo2max-rockport", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"heart_rate": 140,
"weight": 70,
"age": 40,
"sex": "male",
"time_min": 15.5
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "health.vo2max_rockport",
"status": "queued",
"_links": {
"result": "/tasks/tsk_…/result"
}
}The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.
Pricing
Published price — no tokens, no invented credits. A failed task is never charged.
Limits
max_age | 120 |
max_weight_lb | 1000 |
max_time_min | 60 |
max_hr | 250 |
Errors
| HTTP | Code | Meaning |
|---|---|---|
401 | unauthorized | Missing or invalid API key. |
402 | insufficient_balance | Your balance doesn't cover the task price. |
404 | unknown_type | That task type doesn't exist. |
429 | rate_limited | Too many requests. Use the webhook instead of polling. |
Technical notes
What the Rockport estimate means and what the response contains
This calculator returns vo2max_ml_kg_min as the primary result, echoes time in decimal minutes and a clock display, heart rate, weight in both pounds and kilograms, age, sex label and numeric sex code, the unit string ml/kg/min, a method tag rockport_fitness_walking_test, the precision used, and a short formula reminder. Invalid cases fail with invalid_input and are not charged. Rejected inputs include missing time, heart rate, weight, age, or sex; non-finite values; and any non-positive time, heart rate, weight, or age, because the regression was never defined for zero or negative physiological quantities.
How inputs are read and how the equation stays reproducible
Age is years as a positive number; sex accepts male or female, single-letter m or f, man or woman, and numeric codes one for male and zero for female, matching the published sex coefficient of six point three one five. Computation uses only finite arithmetic: VO2 max equals one hundred thirty-two point eight five three minus zero point zero seven six nine times weight in pounds minus zero point three eight seven seven times age plus six point three one five times the sex code minus three point two six four nine times time in minutes minus zero point one five six five times heart rate. Walk time can be supplied as time_min in decimal minutes, such as fifteen point five for fifteen minutes and thirty seconds, or as a time clock string like fifteen colon thirty, with aliases walk_time, duration, and clock. Heart rate accepts the preferred field heart_rate and aliases hr, pulse, bpm, and ending_hr, and must be a positive finite number of beats per minute. Weight is a positive finite number with optional weight_unit defaulting to kilograms; set weight_unit to lb or pounds when the scale reads in pounds. The original Rockport coefficients use weight in pounds, so kilogram inputs are converted with the exact international pound factor before the regression runs, and both weight_lb and weight_kg appear in the response for auditability. Optional precision, with aliases decimals and dp, controls decimal places on the numeric fields, defaulting to four and capped at fifteen so JSON goldens stay stable. Pair the free browser run on this page with the priced API when you need the identical mathematical result inside an automated coaching or research pipeline.
Where the Rockport walk test fits in coaching, education, and software
Product teams use the endpoint when a form collects mile time, pulse, weight, age, and sex and the UI must show millilitres per kilogram per minute without shipping a custom implementation of the Kline equation. On this page the work runs entirely in your browser; through the API each successful lookup costs $0.002, failed validation is not charged, and nothing is stored after the response returns. That split — free interactive exploration and a priced, identical API — matches the rest of the KIT tier-A catalog and lets you move from a classroom demo to an automated pipeline without changing the mathematical result.
Integration use cases
Fitness app fixtures
Seed unit tests and CI with deterministic vo2max_ml_kg_min values from known walk time, pulse, weight, age, and sex.
Technical questions
Which formula does this tool use?
The Kline et al. (1987) Rockport Fitness Walking Test regression: VO2max = 132.853 − 0.0769×weight_lb − 0.3877×age + 6.315×sex − 3.2649×time_min − 0.1565×HR, with sex coded 1 for male and 0 for female.
Can I enter weight in kilograms?
Yes. weight_unit defaults to kg; set it to lb if your scale is in pounds. The equation uses pounds internally and the response echoes both units.