TriCoo

Swim pace and CSS calculator

Pace per 100 m, triathlon swim times, CSS estimate and zones

Pace and time

m

/100 m

If your time includes rest at the wall, the pace includes it too

Time at a constant pace
400 m8:00
750 m, sprint15:00
1500 m, Olympic30:00
1900 m, 70.338:00
3800 m, full1:16:00

Assumes the same pace throughout, with no stops

Everything is calculated in your browser. Your numbers stay on your device

CSS estimate from 400 m and 200 m

CSS

2:00 /100 m

CSS gives an estimate of your threshold pace in the pool. The result depends on how the test was done and does not set a pace for a long swim

Reference TriCoo zones from the threshold you entered. The calculator does not check the threshold or pick a workout. A bound shared by two zones belongs to the harder one, numbers are rounded
ZonePace per 100 m
Z1Easy, recoveryslower than 2:30
Z2Easy, endurance2:30 to 2:13
Z3Moderate, tempo2:13 to 2:04
Z4Hard, around threshold2:04 to 1:57
Z5Hard, above threshold1:57 and faster
How the TriCoo plan is built

How we calculate

Pace per 100 m is the time multiplied by 100 and divided by the distance in metres. The time over another distance is worked out the other way, at the same pace. If your time includes stops at the wall, they are in the pace too.

We estimate CSS from two separate swims of 400 m and 200 m: the difference in time divided by 2 gives the seconds per 100 m. The 200 m has to be faster on average, otherwise there is no estimate. If the result falls outside the range the test method covers, we don't build zones from it.

The five swim zones come from CSS with the TriCoo table: 80, 90, 97 and 103 percent of the speed at CSS. How to do the test is on the Threshold tests page.

Common questions

How do I work out my swim pace per 100 m?

Enter the distance and the time, and the calculator shows the pace. For example, 400 m in 8:00 is 2:00 per 100 m.

How long does 1500 m take at a 2:00 pace?

30 minutes, if you hold the pace evenly. Times for triathlon swim distances are in the table below the fields.

What is CSS?

CSS, critical swim speed, is an estimate of your threshold pace in the pool. With just two numbers the calculator cannot check that the test followed the protocol. So the result stays an estimate and does not count as a confirmed threshold.

Can I use CSS in open water?

Not directly. Open water has no walls, it has waves and you have to sight, so the pace is different. CSS does not set the pace of a long swim or a triathlon swim.

Other calculators