ITRA Calculator: Km-Effort, Category & Index Estimate

Free ITRA calculator. Enter distance, elevation gain and finish time to get km-effort, the XXS to XXL race category and an indicative performance index. UTMB, CCC and OCC examples included.

How It Works

  1. Enter the race distance in kilometres and the total elevation gain in metres
  2. Enter your finish time, or the time you are targeting
  3. Read the km-effort, the ITRA distance category, your effort speed and an indicative band

Km-Effort Formula

km-effort = distance_km + (elevation_gain_m / 100)

This is ITRA's published formula and the calculator uses it exactly. A 42 km race with 2000 m of climb is 42 + 20 = 62 km-effort.

ITRA Distance Categories

Category Km-effort
XXS under 25
XS 25 to 44
S 45 to 74
M 75 to 114
L 115 to 154
XL 155 to 209
XXL 210 and above

Reference Races

Race Distance Gain Km-effort Category
UTMB (Chamonix) 176 km 10,000 m 276 XXL
CCC 100 km 6,100 m 161 XL
OCC 56 km 3,500 m 91 M
Western States 100 161 km 5,500 m 216 XXL
Zegama-Aizkorri Marathon 42 km 2,736 m 69.4 S
Eiger Ultra Trail E51 51 km 3,100 m 82 M

Course profiles change year to year — check the organiser's current data before planning against these.

The Performance Band (Important Caveat)

This tool cannot calculate an official ITRA Performance Index. Neither can any other free tool. ITRA's Performance Index is proprietary, compares your result against the whole field and the historical quality of the race, and can only be issued by ITRA from verified results at itra.run.

What this tool gives you is an indicative band. Effort speed (km-effort per hour) is normalised towards a 100 km-effort reference with a Riegel-style exponent so short and long results are comparable, then mapped onto seven bands from Developing through International. Use it to track your own trajectory and to sanity-check a goal, not for race registration.

ITRA Index vs UTMB Index

Two separate systems run by two separate organisations. ITRA's Performance Index covers races on the ITRA calendar; the UTMB Index is UTMB's own system used for the World Series and Running Stones. Both are broadly on a 0-1000 scale and both need verified results.

Improving Your Km-Effort Speed

Km-effort weights climbing heavily, so vertical-specific work moves the number fastest: sustained climbing at threshold, downhill running for eccentric tolerance, and enough long-run volume to hold pace late. Additional flat mileage generally does not.

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