Pace converter
Type a pace, get it back in every unit that matters — and what it adds up to over 5K, 10K, the half and the full.
Open the toolRace time predictor
Take a race you have actually run and project it onto nine other distances, using Riegel's equation with the fine print attached.
Open the toolHeart-rate zones
Five zones from your maximum. Add your resting rate and it switches to heart-rate reserve, which fits most people better.
Open the toolClimb calculator
Your FTP and weight into watts per kilo, and honest times on seven famous cols and two big sportives.
Open the toolAero lab
Where your watts actually go on the flat, and what each upgrade is really worth at your speed.
Open the toolVO2max estimate
From your resting and maximum heart rate, a steady ride with a power meter, or a steady run at a known pace — each with an honest range, every number traced to its source.
Open the toolWhat every one of these tells you
Each tool has a section called Under the hood: the sum it actually does, and a line-by-line table of the numbers that go into it — where each one comes from, and which ones are our own assumption rather than something anyone measured. Those are marked.
That is not modesty for its own sake. A calculator hands you a number that looks like a fact, with no argument around it you can weigh. The least we can do is show you which parts of that number are solid and which are a judgement call.
Use one of these on your own site
Club site, blog, coaching page: any of the six calculators drops in with one line of code. It sets no cookies, measures nothing on your page and sizes itself. How to embed a calculator →
Missing a tool?
These six are the start. If there's a calculator you keep wishing existed — fuelling planner, heat-adjusted pace, whatever keeps you up at night — tell us: mail info@enduranceproof.com or ping @EnduranceProof_ on X, and we'll put the best ones on the bench.
We write when a new tool or piece is finished, and not otherwise. One click to leave.