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Track Split Calculator

Your session

The pace you intend to hold for every rep — the same number for a 200 m repeat and a 1600 m repeat. The page opens on 4:45 per km as a worked example; put your own pace in.

Lane 1 is the measured 400 m line. Every lane out is longer, because the bends are bigger — the whole point of the first table below. The page opens on Lane 2, which is where most sessions are run.

or press Enter

Goal pace

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Lane lap distance
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In miles
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Extra per lap vs lane 1
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Laps per mile
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One lap at your pace
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Rep splits

Rep On the track Laps Split Clock

Lane by lane

the same 400 m geometry behind the lap column

Lane Radius m Lap m vs lane 1 Lap time

What this page does

A track split calculator usually answers one of two questions and not both. Ask about the rep and you get a split table — 200 m in such a time, 400 m in such a time. Ask about the lane and you get a lap-length table. The two never meet, and on a real track session they have to, because the lap you are actually running is not 400 m unless you are in lane 1 with a clear inside line, and the clock does not care which table you were looking at.

This page puts all three things on one screen from one goal pace and one lane choice:

  • The lane distances, 1 to 8. Each lane's full-lap distance, computed from the published track geometry rather than copied from a table, with each lane's correction against lane 1 shown beside it.
  • A full rep table. Twelve standard track distances — 100, 150, 200, 300, 400, 600, 800, 1000, 1200, 1600 m, one mile and 3200 m — with the split for each from your goal pace.
  • The cumulative clock. Beside every rep, the running total at the end of that rep, so the number on the clock when you come through is the number printed here.

Everything runs in your browser. There is no server, no account and no upload, and the pace you type never leaves the page. If your session is a race rather than a track workout, the running split calculator prints an even-split band for any road distance; if it has hills in it, the race time calculator prices those. Neither of them knows what a lane is, and this page is the one that does.

How the number is calculated

The lane distances are the one part of this page that can be worked out rather than looked up, so they are worked out. A 400 m track is two straights joined by two half-circles. The straights have a published length and the bends have a published radius, so the length of a lap is just the perimeter of that shape:

lap = 2πr + 2s

  • s — the length of one straightaway, 84.39 m.
  • r — the radius of the circle the bend is part of, 36.5 m for the inner line of lane 1.
  • 2πr — the two bends together, which is one whole circle.

Those two figures are the standard dimensions of a 400 metre running track as set out in the sport's facility rules — the World Athletics (formerly IAAF) Track and Field Facilities Manual, 2019 edition, which gives a 36.50 m radius for each semicircle and 84.39 m straightaways, and a nominal lane width of 1.22 m. The page does not take a table of lane distances from anywhere: it takes those four constants and derives every lane from them, which is why the working below can be checked line by line.

Put the inner-line radius straight into that formula and lane 1 comes out at 398.12 m, not 400. The 400 is a racing distance, not a piece of geometry: the measurement is taken 0.30 m out from the inner line, to stand for the width of the runner's body, so the radius that is actually used is 36.5 + 0.30 = 36.8 m. With that one number the same formula returns:

2×π×36.8 + 2×84.39 = 231.26 + 168.78 = 400.00 m

Every outer lane is the same shape with a bigger radius. Lanes are 1.22 m wide, so lane n uses a radius of 36.8 + (n−1)×1.22 m and the same formula again. Because the straights do not change with the lane — only the bends do — the extra distance per lane is exactly the two bends' difference:

Δ = 2π × 1.22 = 7.665 m per lane

That single number is what makes the first table checkable by hand. Every lane should sit 7.665 m further out than the one inside it, and further out than lane 1 by that multiple:

  • Lane 2 — r = 38.02 m, lap = 407.67 m, which is 400.00 + 7.665 = 407.665 to the millimetre.
  • Lane 4 — r = 40.46 m, lap = 423.00 m, which is 400.00 + 3×7.665 = 423.00.
  • Lane 8 — r = 45.34 m, lap = 453.66 m, which is 400.00 + 7×7.665 = 453.66.

Those three checkpoints are worth keeping, because a published table usually rounds to one decimal (407.7, 423.0, 453.7) while the formula gives two. The page prints what the formula gives, and the numbers would still be right if every published table disappeared.

The rep splits are the easier half: your goal pace is a time per distance, so the split for a rep is just the pace multiplied along the rep.

split = pace × rep distance   ·   clock = running total of the splits

No model, no correction factor and nothing fitted. The lane only enters the arithmetic through the laps column — how many laps a rep is in the lane you chose — and through the lap time in the second table, which is your pace multiplied along one lap of that lane. What the page deliberately does not add to the rep splits is recovery: the splits assume you run each rep at the goal pace, and the rest between them is yours. That is stated again below rather than left for you to discover.

What it accepts, and what it will not guess

  • Goal pace — any minutes-and-seconds from 1 second up. Below 3:00 per km the pace is faster than a world record over any track distance, but the page will still do the multiplication, because telling you the arithmetic is wrong is not the same as telling you the workout is.
  • Pace unit — per kilometre, per mile or per yard. Track sessions are still often written in minutes per mile (a "6:00 mile pace"), and some club sessions are written per 400 m; per yard is included for those. Per mile and per yard are converted exactly: a mile is 1609.344 m and a yard is 0.9144 m, both exact definitions.
  • Lane — 1 to 8 only. Eight is where almost all permanent tracks stop, and lanes 9 and 10 exist only on some sprint tracks; inventing a ninth lane would mean inventing a geometry.
  • Rep distances — the twelve listed. If your session is a 625 m or a 3-mile rep, the arithmetic is pace × distance and you can do it from the per-minute number; this page does not carry a box for every distance, because a table of twelve is what a session actually uses.

What this page deliberately does not do

  • No race staggers. The lane table answers a practice question — how far is one lap if you start and finish on the same line. Official race starts move the outer lanes forward so that every athlete covers the same racing distance, and those start lines are marked on the track you are standing on. This page does not compute them and says so rather than printing a stagger that would be wrong on a legacy facility.
  • No recovery times. The rep table is splits and clocks only. The rest between reps depends on the session's purpose, and this page has no way to know it, so it is left out entirely instead of being filled with an invented default. The lanes table has no rest in it either, for the same reason.
  • No pace band and nothing to print and wear. A session sheet is a table you glance at between reps, not a band on a wrist — the marathon pace band and the running split calculator are the two pages that draw one.
  • No race predictions and no equivalent performances. This page takes a pace you have already decided on and turns it into splits. What you are capable of over a track distance is a different question, and the predictor on the home page is the page that answers it.
  • No fall or fatigue in the pace. Your goal pace is held flat across every rep, so the tenth 400 m has the same split as the first. Real sessions slow down, and the amount they slow down is not something this page knows.
  • No facility-specific geometry. Every lane number here comes from the standard figures above. A very old track, or one measured to a different convention, can differ by a few metres a lap, and a handheld watch will read something a little different again because it follows the path you actually ran. If the track has a measurement certificate, its numbers beat this page's.
  • No shoe, surface or wind correction. None of those is modelled anywhere on this page and none of them is silently baked in.

Questions

What is a track split calculator?

A track split calculator turns a goal pace into the time each rep should take on a running track. This one does that for twelve standard rep distances at once, and it also shows the lap length of the lane you are training in, so the split and the lap it is run on sit on the same page. The lane part matters because a lap in lane 2 is 407.67 m, not 400, and a session planned as "six laps" is not the distance you thought it was.

Why is a lap in lane 2 not 400 metres?

Because the measurement line that defines the 400 m is inside lane 1, 0.30 m out from the kerb. Move out into lane 2 and the radius of the two bends grows by the lane width, 1.22 m, while the straights stay 84.39 m each. The lap therefore grows by 2π × 1.22, which is 7.665 m, and lane 2 comes to 400.00 + 7.665 = 407.67 m. Lane 3 is another 7.665 m on top of that, and so on round the track.

How many laps of the track is a mile?

It depends on the lane, and this is the clearest place to see why the lane table is not decoration. A mile is 1609.344 m, so in lane 1 it is 1609.344 / 400.00 = 4.02 laps. In lane 2 the lap is longer, so it takes fewer of them: 1609.344 / 407.67 = 3.95 laps. By lane 8 the same mile is 3.55 laps. The second table prints that figure for whichever lane you selected, and the rep table uses it to work out how many laps each rep is in your lane.

Is the mile row the same as the 1600 m row?

No, and the difference is worth about nine metres. 1600 m is exactly four laps in lane 1. A mile is 1609.344 m, so the mile row is always a little slower than the 1600 m row at the same pace: at 4:45 per kilometre the 1600 m split is 7:36 and the mile split is 7:39. The page keeps both rows rather than hiding one, because a session written as "4×mile" and a session written as "4×1600" are not the same session.

Does it count the recovery between reps?

No. The rep table is splits and clocks only, and the clock is the time at the end of each rep as if the reps were run back to back. Rest is not in the table, is not added to the clock, and is not guessed. The page says this in the "does not do" list as well, so nobody plans a session around a number that was never there.

Where do the lane distances come from?

From the formula, not from a copied table. The page uses a straightaway of 84.39 m, a lane-1 inner-line radius of 36.5 m, the 0.30 m measurement offset that turns the inner line into the racing line, and a nominal lane width of 1.22 m — the standard figures for a 400 m track. It then computes lap = 2πr + 2s for each lane. The values it produces (400.00, 407.67, 415.33, 423.00, 430.66, 438.33, 445.99, 453.66) are listed on the page beside the radius each one came from, so you can redo any line with a calculator.

How is this different from the running split calculator?

The running split calculator is for a road race: you give it a finish time and a distance from 400 metres to 100 miles and it draws an even-split band you can print and wear. This page is for a track session: it has no finish time, no band and no printable card, and instead of one distance it gives a table of reps and the lane arithmetic behind the lap you are running them on. Both take a pace; only one of them knows what a stagger is.