The pace calculator
runners actually use

Pace equals total time divided by distance. Example: a 26-minute 5K is 26 ÷ 3.1 miles = 8:23 per mile. The calculator above does this automatically — enter any two of pace, time, and distance and the third is computed instantly, along with splits for every common race distance.

Riegel's formula predicts your time at a new distance: T₂ = T₁ × (D₂ / D₁)^1.06. Example: a 45:00 10K predicts a marathon of 45:00 × (26.2 / 6.2)^1.06 ≈ 3:28. The 1.06 exponent accounts for fatigue — longer distances run proportionally slower. It is accurate within roughly 3 percent for trained runners between 5K and the marathon.

Daniels derives five training paces from your VDOT (a fitness score from a recent race): Easy (E) for recovery and long runs, Marathon (M) for race-specific work, Threshold (T) at lactate threshold, Interval (I) at VO₂ max, and Repetition (R) for speed and economy. A single race time anchors all five — the calculator above outputs them automatically.

Divide the min/mile pace by 1.609. Examples: 8:00 per mile ÷ 1.609 = 4:58 per km. 7:00 per mile = 4:21 per km. 6:00 per mile = 3:44 per km. The calculator displays both side by side so no manual conversion is needed.

A sub-4:00 marathon requires 9:09 per mile (5:41 per km). Splits: 5K in 28:25, 10K in 56:50, half marathon in 1:59:30. Run the first 5K about 10 seconds per mile slower than goal pace, lock onto 9:09 from mile 3 onward, then target a small negative split in the final 6 miles.

A 5K predicts a 10K within about 2 percent for most runners, a half marathon within about 4 percent, and a marathon within about 6 to 8 percent. The marathon prediction is less reliable because finishing time depends heavily on endurance training, fueling, and pacing discipline — not just raw speed. Predictions from a recent half marathon are more accurate for marathon goal-setting.

Easy pace is typically 60 to 90 seconds per mile slower than marathon pace. For a runner with a 4:00 marathon goal (9:09 per mile), easy runs sit around 10:15 to 10:45 per mile. Easy pace builds aerobic capacity without accumulated fatigue; marathon pace teaches race-specific economy. Roughly 80 percent of weekly miles should be easy.

Yes for walking — the pace, time, and distance math is identical. For cycling, the splits and training-pace logic do not apply (cyclists train by power, not pace), but the basic pace-to-time conversion still works for any speed.