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Heart rate zones
Five zones, by Karvonen or by plain percentage.
It runs entirely in this browser tab: what you type is never uploaded, and the tool makes no network request while it works. Open your browser's network panel and try it — nothing leaves the page. There is no sign-up and no account.
What it takes
- Age (years)
- A value you supply.
- Resting (bpm)
- A value you supply.
- Maximum (bpm)
- Optional.
An example
age = 40
resting = 60
Settings
- Zone method
- Karvonen works off the reserve and needs a resting rate. Choices: Karvonen, Percentage of maximum.
- Sex
- Every formula here was fitted separately to men and to women. Choices: Female, Male.
How to use it
- Fill in the boxes above. Anything you leave blank the tool works out.
- Adjust the settings beside it until the result is what you wanted.
- Copy the result, or save it as a file. The result updates as you type.
Questions
- Is this medical advice?
- No. It is arithmetic on the numbers you supplied, with the formula named, and it says so on every result. Nothing here diagnoses or prescribes.
- Where do the numbers in the formula come from?
- From published equations, each named on the result, and from whatever you typed. Nothing is looked up: there is no drug database, no national schedule and no reference range invented to fill a gap. Where a tool has no answer it says so with the reason.
- Is what I type uploaded anywhere?
- No. This page carries the whole tool as WebAssembly and runs it on your own device. Nothing you type is sent anywhere, which for a health calculator is the point rather than a feature.
- Is there a version that is not a web page?
- Yes. The same tools are built as a desktop application from the same code, with a save dialog instead of a download and no network code at all.
Other tools for fitness
Maximum heart rate
Five estimates, and the twelve beats of error on all of them.
VO₂ max
Three field tests, and where the result sits for your age.
One-rep max
Four formulas, the whole percentage table and the plates to load.
Calories burned
An hour of something, from the metabolic-equivalent table.
Steps to distance
A pedometer's number, through a stride you measured or estimated.
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