Why it exists
Most sports calculators on the internet share the same problem: they give you a number and do not tell you where it comes from. You cannot see what model they use, what they assumed on your behalf, or how far off they might be. And in endurance sport, a number without its error margin is an elegant way to be wrong with confidence.
This site grew out of that frustration. Every calculator publishes the equation it applies, the assumptions it makes and the expected error range, and every page explains why the model works better under some conditions than others. The idea is that you can argue with the result, not just accept it.
Where the formulas come from
None of the models is original. They all come from published, established literature:
- Cycling — the power equation of Martin, Milliken, Cobb, McFadden and Coggan (1998), and the critical power model of Monod and Scherrer, with the power profile categories of Coggan and Allen.
- Swimming — critical swim speed from Wakayoshi and colleagues, and the distance-time power law for predicting between distances.
- Running — Riegel's formula for predicting between distances and the gradient energy cost curve of Minetti and colleagues (2002).
- Triathlon — intensity and accumulated fatigue factors from documented practice in training with power, applied on top of the three models above.
When a model is applied outside the range it was validated for, the page says so.
Who writes it
DigitalAsteroid is a small, independent project: there is no editorial team and there are no sponsors. Behind it is a triathlete who trains, measures and gets things wrong, with a technical background and the habit of wanting to understand the formula before trusting the result. The same models you see here are the ones underpinning the training logs we publish on paper.
How it is funded
In two ways, both declared:
- Advertising from Google AdSense, kept separate from the content and never disguised as a result.
- Affiliate commissions from Amazon on the DigitalAsteroid training logs linked at the end of the calculators.
There is no sponsored content, no paid reviews and no brands deciding what gets published. If that ever changed, it would be marked on the page itself.
Errors and suggestions
If you find a calculation error, a badly referenced table or a translation that grates, write to contacto@calculadorasdeportivas.com. It gets fixed and it is appreciated. If a calculator is missing, the same applies: the list of upcoming ones comes largely from what people ask for.