Ironman finish time = your half-marathon result * a multiplier of 2.1
Here, we take the analysis a step further: defining the average multiplier for each age group. We analyzed the relative range of tough (Texas, with a 2.17 overall multiplier) and average (New Zealand, average multiplier of 2.12) ironman and half ironman 70.3 combinations.
Interestingly, the multipliers do vary across many age groups. Most fluctuate slightly above the 2.1 multiplier, with Texas exceeding New Zealand in most age groups. Notable exceptions are men aged 18 to 39, which see a higher multiplier at New Zealand, while women 18 to 54 have it tougher in Texas.