About Race Time Predictor

Race Time Predictor is one free page that turns a race you have already run into the finish time your current fitness is worth at a different distance — plus the pace and the split plan that go with it.

What this site is

One tool, one page, no account. You enter a recent race and a target distance; the page does the arithmetic in your own browser and shows the answer. There is no sign-up, no email capture, no paywall and no daily limit.

It is a calculator, not a training plan. It reads the fitness you have already demonstrated and moves it along the distance curve. It does not know how much endurance work you have done, and it does not pretend to.

Who runs it

Race Time Predictor is built and maintained by an independent operator, and it is published under the site name only. There is no company behind it and no team. Questions, corrections and reports of broken pages go to the address on the contact page.

How the site is paid for

There is no advertising on this site today and nothing on it is for sale. If that changes, the privacy page will be updated to name the provider before any advertising code goes live. That is a commitment, not a placeholder.

What it deliberately does not do

No age or sex grading, no weather correction, no elevation model, no bulk mode, no accounts and no saved history. Each of those needs either a published data source or a server, and this page has neither. Shipping an unsourced adjustment would make the number look more precise than it is.

Where the maths comes from

The default engine is Peter Riegel's endurance equation, published in 1981 and still the standard baseline in running. The home page sets out the formula, the unit definitions and the limits of the method in full.

— Race Time Predictor