Use your IRONMAN 70.3 time to predict your 140.6 result.

Dark Arts

When estimating your performance for an IRONMAN event, please appreciate that it is certainly more art than science. It’s a guesstimate and a lot of things have to fall into line for your 70.3 PB to be extrapolated to a reasonably estimated 140.6 time.

Look at what you know

Instead of solely relying on the sum of personal bests or an average extrapolation of shorter distances within each swim, bike and run discipline; a more nuanced approach involves looking at your training sessions that have been tailored to race intensity. These sessions might entail sustained efforts at target race paces or structured intervals mirroring race demands and may (with the additions of transitions) provide a better picture of what you may be able to achieve.

Accounting for IRONMAN race experience adds another layer of complexity. Seasoned athletes possess a sweaty treasure trove of performance data for accurate projections, whereas novices don’t have those success and failures from which to draw a guideline. Elevation changes, weather, and terrain profoundly affect performance and should also be noted when looking at time estimates.

Data suggests

That said, you are likely here to simply extrapolate from an IRONMAN 70.3 result. So, how do we do that? Data suggests that multiplying the total minutes of your 70.3 result by 2.15 to 2.22 should get you in the right ball park.

For many, this may produce surprising results. The longer distance event requires a much better focus on the three key areas of pacing, fuelling and hydration. Any mistakes being made in an IRONMAN 70.3 can certainly have consequences. But, make them on a 140.6 and you can be in all sorts of trouble. The longer event magnifies mistakes and provides ample more time when things are already difficult, for things to get even worse.

Get your prediction

Ok, so, on with the show. Drop your 70.3 numbers in below and see your predicted time based on the equation above.

Time Calculator


Enter your 70.3 time below.

Hit the calculate button and your predicted times will appear below.

Does the Prediction look scary?

If the predicted IRONMAN time feels daunting, let me be the coach to help you bridge that gap. As your personal Ironman coach, I specialize in turning daunting goals into finish line celebrations; crafting a custom training plan that fits your unique strengths and one that is tailored to your busy lifestyle. Let’s get your journey started. Send me an email to discuss.

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