Endurometry
What does this calculator do?
From one goal time the chart page prints: even splits in min/km and min/mile, a speed↔pace grid (6.0–20.0 km/h), Daniels-style intensity bands from the VDOT of that goal, and the same wrap-around even wristband as the band page.
Splits and the speed grid are exact. Intensity rows are a published model (Daniels–Gilbert VDOT + published % bands). The band on this page is even only.
How does it work?
Goal pace = time / distance. Split clocks are n × pace (plus a true-distance finish row). The speed table inverts v km/h → 3600/v s/km. VDOT comes from the same oxygen-cost / duration pair as race prediction; Easy 59–74%, Marathon 75–84%, Tempo/Threshold 83–88%, Interval 95–100% of that VDOT. %HRmax labels on those rows are coaching ranges, not Karvonen.
Formula
pace/km = T / D pace/mi = pace/km × 1.609344 km/h = 3600 / pace_s_per_km VDOT = vo2(v) / %VO2max(T) // Daniels–Gilbert zone pace = inverse VO2(VDOT × p)
Paces to a second; speeds two decimals; VDOT one decimal. Goal 1 min–8 h.
Worked example
Default: marathon 4:00:00, km splits, interval 5, wrist M.
- Pace 5:41/km · 9:09/mi · 10.55 km/h
- Even 5 km cumulative at 10 km = 10 × 5:41 → 0:56:53 on the clock
- VDOT from 42.195 km in 4:00:00 (same engine as race prediction)
- Tempo row = 83–88% of that VDOT, in min/km and min/mi
- Wristband even, last mark 42.195 km at 4:00:00
Generate: 5:41/km, dual-unit split table, speed grid, VDOT zones, even band.
How to interpret the result
The big 5:41 is the even race pace. Tempo on this page is “threshold as a fraction of the VDOT implied by your goal,” which is only valid if that goal is realistic. A 4-hour marathon VDOT is not your 5K VDOT.
Full zone table from a recent race: training pace calculator. Wristband with negative splits: printable wristband.
Assumptions and limitations
Assumptions
- Even race pace equals T/D.
- VDOT treats the goal as a performance you could produce today.
- Speed grid is unit conversion, not a treadmill converter.
Limitations
- Intensity %HRmax is a label, not Karvonen from your resting HR.
- The embedded band is even; change strategy on the wristband page.
- No hills or GPS correction.
- Times outside 1 min–8 h rejected.
Methodology and sources
Method type: Published model
Split and speed tables are exact (NIST mile, World Athletics distances). Intensity rows implement Daniels–Gilbert VDOT and the same published % bands as the training-pace calculator. The wristband geometry matches the printable band page (even strategy).
- Methodology: Pace, speed and distance
- Methodology: Speed and unit conversion
- Methodology: Training paces (VDOT zones)
- Methodology: Rounding and displayed precision
Sources: NIST SP 811 · World Athletics Book of Rules · Daniels–Gilbert 1979 · Daniels’ Running Formula
Last reviewed: October 5, 2026