Adjusting 100m Performance


I have posted a new calculator on my website which adjusts 100m sprint times for what’s called “density altitude”. This is an effective altitude which is different from the physical elevation of the track, and is affected by temperature, barometric pressure, and humidity.
The calculator is here:

Enjoy. If you have any questions, please email me at


I have always wondered how the windspeed affected sprint performance.

According to the calculator at sea level under “default” conditions the time of a 100m race run in 10.0 can vary between 9.86 and 10.09 within the legal wind limit ±2m/s.

I don’t know what the wind speed was for 9.78 but assuming it was 0 m/s according to this that could have been as slow as 9.87 or as fast as 9.64! Do environmental conditions really make this much of a difference?

I wonder if the track surface conditions were taken into consideration when calibrating this thing (or perhaps it was calculated purely from theory).

Food for thought!

No London in options!!?Interesting calculator though.

Powell’s 9.77 time was with a +1.6 wind so it’s about 9.85 I believe no wind. Therefore technically it is not the fastest run ever but it is the fastest time ever.

However I don’t trust these calculators, if they are correct then someone who ran a 12.1 into a -2 wind one week later ran an 11.86 into a -5.2 wind. That’s like a .6 improvement or something according to these in 1 week? These calculators have some explaining to do.

We’ve had these discussions before. Who says the variables accepted ca be relied on? Wind readings for instance, when Ashford’s 10.96 was ranked ahead of Gohr’s 10.88 in 1982 cause of a supposedly neg wind when the race had been turned around to get a tailwind and the wind meter was left in place- hence a pos wind was called neg. Another example was in Seville when Ben beat Carl in a fairly average time of 10.06 (Ben was nursing a calf injury) and the -.26 wind was officially recorded as -2.6 as I recall, making the race appear to have been far faster than it was.
What if the idiots in Edmonton hadn’t discovered their mistake with the wind readings??

Sorry, what does this refer to?

I would assume Charlie was talking about the World Champs in Edmonton. MLF ran 9.97 but this time couldn’t be ratified due to a faulty wind gauge.

They announced that guys were running sub10 with minus 5.5 wind readings

That would be impressive! Those were the days when MLF was good and GB had a future in the sprints. Lets hope Craig Pickering can keep on improving and stay injury free.

Even in Helsinki, for the 100m and 200m races, i absolutely don’t trust the wind readings. This stadium is a wind trap. I even took pictures the flags at different points on the track which were showing opposite directions, i couldn’t believe my eyes… It was really unfair for the qualification times in heats… Such calculations work in theory, but are non-sense if applied for Helsinki…

The only other place that these calculations don’t work is… everywhere else!

This was the same at Mt. Sac for the last couple of years. The flags alongside the track would be showing a strong tailwind (and you could feel it alongside the track), yet the wind guage varied between -3 and +3 m/s during the 100m. Yet I’m quite certain (based on casual observation of flags) that the wind didn’t change direction.