Track Lane Distance and Stagger Calculator
Track Lane Distance and Stagger Calculator
The exact length of one lap in any lane, and the stagger that makes a one-lap race fair, from the kerb radius, the lane width and the straight. It reproduces World Athletics’ own 400 m marking plan to the millimetre.
Lane length and stagger
Two bends and two straightsLane 8 of the IAAF 400 m standard track: 1.22 m lanes, 36.50 m kerb radius, 84.39 m straights
Formula
measurement radius, lane n ≥ 2 = kerb radius + (n − 1) × lane width + 0.20
one lap = 2 × straight + 2 × π × measurement radius
stagger for one lap = 2 × π × (radius of lane n − radius of lane 1)
marking plan stagger = 2 × ceil(π × radius difference, to the mm)
- 0.30 and 0.20
- Technical Rule 14.2, the measurement “shall be taken 0.30m outward from the kerb or, where no kerb exists on a bend … 0.20m from the line marking the inside of the track”, and Rule 14.4, “the remaining lanes shall be measured 0.20m from the outer edges of the lines”. The two offsets differ, which is why lane 2 is only 7.04 m longer than lane 1 while lane 3 is 7.67 m longer than lane 2
- 1.22 m
- Technical Rule 14.4: each lane up to and including 400 m is “1.22m ± 0.01m”, including the 50 mm line on its outside. An input here, because the tolerance is real and narrower tracks exist
- 36.500 and 84.390
- the IAAF Track and Field Facilities Manual, 2008 edition, Figure 2.2.1.6a: construction radius including the raised kerb 36.500 m, each straight 84.390 m, lane 1 measurement line 36.800 m, each bend along the line of running 115.611 m. Inputs here, because a 200 m indoor and a 300 m training track have neither
- the straight does not affect the stagger
- the straights are identical in every lane, so they cancel in the difference. The stagger is 2π times the radius difference and nothing else — the easiest property to test a lane calculator against
- ceil, to the millimetre
- the marking plan’s published staggers are each exactly one millimetre per bend larger than the exact geometry, which is the geometric figure rounded UP to the next whole millimetre. The manual does not say why in the text read for this page
Worked example
Lane 8 of the IAAF 400 m standard track: 1.22 m lanes, 36.50 m kerb radius, 84.39 m straights
Lane 8's measurement line sits at 36.50 + 7 × 1.22 + 0.20 = 45.240 m, the radius the manual prints for lane 8
One lap is 2 × 84.39 + 2π × 45.24 = 453.031 m, against the manual's 453.030
Lane 1's line is at 36.800 m and its lap is 400.0012 m — the manual prints 400.001, so the standard track is a millimetre over 400 m
The radius difference is 8.440 m, so the exact stagger is 2π × 8.44 = 53.0301 m, and rounded up to the millimetre per bend 2 × ceil(π × 8.44) = 53.032 m — the manual's published 400 m figure exactly
Half of that, 26.516 m, is the manual's published 200 m stagger for lane 8 exactly: one bend instead of two
The step from lane 7 to lane 8 is 2π × 1.22 = 7.6655 m; from lane 1 to lane 2 only 2π × 1.12 = 7.0372 m, because the offset changes
Change the straight to 90 m and every lap grows by 11.22 m while every stagger stays exactly where it was
The IAAF 400 m standard track, lane by lane
| Lane | Radius | One lap | Stagger, 400 m | Published | Stagger, 200 m |
|---|---|---|---|---|---|
| 1 | 36.800 m | 400.0012 m | — | — | — |
| 2 | 37.920 m | 407.0384 m | 7.0372 m | 7.038 m | 3.519 m |
| 3 | 39.140 m | 414.7039 m | 14.7027 m | 14.704 m | 7.352 m |
| 4 | 40.360 m | 422.3694 m | 22.3681 m | 22.370 m | 11.185 m |
| 5 | 41.580 m | 430.0348 m | 30.0336 m | 30.034 m | 15.017 m |
| 6 | 42.800 m | 437.7003 m | 37.6991 m | 37.700 m | 18.850 m |
| 7 | 44.020 m | 445.3658 m | 45.3646 m | 45.366 m | 22.683 m |
| 8 | 45.240 m | 453.0313 m | 53.0301 m | 53.032 m | 26.516 m |
What moves the stagger and what does not
| Change | Lane 8 lap | Lane 8 stagger | Step between outer lanes |
|---|---|---|---|
| Defaults | 453.031 m | 53.030 m | 7.666 m |
| Straight 84.39 → 90.00 m | 464.251 m | 53.030 m | 7.666 m |
| Kerb radius 36.50 → 40.00 m | 475.023 m | 53.030 m | 7.666 m |
| Lane width 1.22 → 1.00 m | 443.345 m | 43.345 m | 6.283 m |
| Lane width 1.22 → 2.44 m | 560.724 m | 106.724 m | 15.331 m |
| Radius and width transposed | 171.146 m | 222.531 m | 229.336 m |
Why lane 2 is not 7.67 m longer than lane 1
This page is about athletics — track and field, and road running — whose competition rules, technical rules and scoring tables are published by World Athletics, the body that was the IAAF until 2019. Where a figure below belongs to a particular edition of those rules, the edition is named beside it, because World Athletics revises them and a number quoted without its edition will be wrong for somebody.
The specification, with its rule numbers, from the World Athletics Technical Rules in the edition carrying amendments effective 1 January 2022. Rule 14.1: “The length of a standard running track shall be 400m”, two parallel straights and two bends of equal radii. Rule 14.2: the measurement “shall be taken 0.30m outward from the kerb or, where no kerb exists on a bend … 0.20m from the line marking the inside of the track”. Rule 14.4: lanes of “1.22m ± 0.01m”, with the remaining lanes measured 0.20m from the outer edges of the lines.
A lap is two straights and two half-circles, and only the half-circles differ between lanes, so the stagger is 2π times the difference between two measurement radii and the straights cancel out of it.
The part almost nothing gets right is where that measurement line sits. Lane 1 is measured 0.30 m out from the kerb; every other lane is measured 0.20 m out from the outer edge of the line on its inside. The two offsets are different, so the step from lane 1 to lane 2 is 2π × (1.22 − 0.10) = 7.0372 m while the step from lane 2 to lane 3, and between every outer pair after it, is 2π × 1.22 = 7.6655 m. A calculator that multiplies 7.67 by the lane number minus one is wrong in lane 2 by 63 cm and in lane 8 by more than four metres.
Two honest wrinkles. The standard track is not exactly 400 m: with the manual’s own construction radius of 36.500 m and straights of 84.390 m, lane 1’s measurement line is 400.0012 m, and the manual itself prints 400.001 for the line of running, so the millimetre is in the specification and not in this page’s rounding. And the manual’s published staggers are each one millimetre per bend larger than the exact geometry. Taking the geometric value and rounding it UP to the next whole millimetre reproduces the manual’s 200 m stagger table exactly for every one of lanes 2 to 8, and doubling that reproduces its 400 m table exactly. The manual does not explain the rounding in the text read for this page, but its direction is the one World Athletics applies to a time and to a wind reading: round so the athlete is never flattered.
Nothing here assumes a 400 m track — indoor tracks are 200 m, training tracks often 300 m, school tracks neither and often not 1.22 m lanes either — which is why all four numbers are inputs. For whether a sprint time on this track can count as a record, the wind reading and altitude legality interpreter has the wind rule and the surprising way a reading is rounded.
Frequently asked questions
How long is lane 8 of a 400 m track?
453.031 m on the IAAF standard track — 1.22 m lanes, a 36.50 m kerb radius and 84.39 m straights. Lane 8’s measurement line is at a radius of 45.240 m, and one lap is 2 × 84.39 + 2π × 45.24. The IAAF Track and Field Facilities Manual gives 453.030.
What is the stagger for a 400 m race?
7.038 m for lane 2 and 7.666 m for every lane after that on a 1.22 m lane width, so 53.032 m for lane 8. The two differ because lane 1 is measured 0.30 m out from the kerb and the outer lanes 0.20 m out from their inside line, under Technical Rule 14.2.
Why is the step from lane 1 to lane 2 smaller than the others?
Because the measurement offset changes. Lane 1’s line is 0.30 m out from the kerb and lane 2’s is 0.20 m out from the line between them, so the radius grows by the lane width minus 0.10 m rather than by the full lane width: 2π × 1.12 = 7.0372 m instead of 2π × 1.22 = 7.6655 m.
Is a 400 m track exactly 400 m?
Not quite. On the IAAF manual’s own construction figures — a 36.500 m kerb radius and 84.390 m straights — lane 1’s measurement line comes out at 400.0012 m, and the manual itself prints 400.001 m for the line of running. Technical Rule 14.1 specifies 400 m; the construction geometry delivers a millimetre more.
Does this work for an indoor or a 200 m track?
Yes, if you give it that track’s numbers: the kerb radius, the lane width and the straight are all inputs and nothing is hard-coded to the 400 m standard. Indoor bends are banked, which this page does not model — a banked bend’s running line is longer than its plan projection.
Related calculators
References
- World Athletics. Technical Rules (Book C, C2.1), copy read 12 Oct 2026 carrying amendments effective 1 January 2022; about 60,000 characters of readable text, truncated before the combined-events material. Rule 14.1, “The length of a standard running track shall be 400m”, two straights and two bends of equal radii, kerb 50mm to 65mm high. Rule 14.2, the measurement “shall be taken 0.30m outward from the kerb or, where no kerb exists on a bend … 0.20m from the line marking the inside of the track”. Rule 14.4, lanes of “1.22m ± 0.01m” with “the remaining lanes … measured 0.20m from the outer edges of the lines”. Rule 14.5, eight lanes minimum at the top international competitions; Rule 14.6, lateral inclination not over 1:100 and downward inclination not over 1:1000.
- IAAF. Track and Field Facilities Manual, 2008 edition — Figure 2.2.1.6a, “Marking plan for the IAAF 400m Standard Track” (© IAAF 2008). Construction radius including the raised kerb 36.500 m; measurement line in lane 1, 0.30 m outside the kerb, 36.800 m; each straight 84.390 m; each bend along the line of running 115.611 m; the track along the line of running 400.001 m; lane width 1.220 m including the 0.05 m line on the outside; lanes 2 to 8 measured 0.20 m out from the outer edge of the inner line. Published staggers, 400m start: 7.038, 14.704, 22.370, 30.034, 37.700, 45.366, 53.032 m for lanes 2 to 8; 200m start: 3.519, 7.352, 11.185, 15.017, 18.850, 22.683, 26.516 m. Read 12 Oct 2026 from the copy hosted by the Vlaamse Atletiekliga; about 5,000 characters, and the construction measurements and both stagger tables came through as readable TEXT while the track diagram is an image. Every figure used here is from the text, not the drawing.
- Wikipedia. Running track (read 12 Oct 2026). An independent corroboration of the IAAF manual’s lane table, which it reproduces with the same radii (36.80 to 45.24 m) and the same lane lengths (400.000 to 453.030 m), and for “the radius of the curve 0.30m (for lane 1) and 0.20m (for lane 2 to lane 8) from the inner side into that lane”. Not a governing body, and nothing here rests on it alone.