Marathon Pace Calculator

Performance declines by approximately 60 seconds per hour for every 5°C above an optimal racing temperature of 10–12°C. Racing in 25°C? Add 90–120 seconds to your per-kilometer pace compared to a cool day.

Never increase your weekly running mileage by more than 10% from one week to the next. This prevents the accumulation of training stress that leads to overuse injuries like shin splints and stress fractures.

Negative splitting means running the second half of a race faster than the first half. It is the pacing strategy used in virtually every marathon world record because it conserves glycogen early and maximizes performance in the final 10km.

Most evidence-based plans are 16–20 weeks for first-timers, 12–16 weeks for experienced runners. The final 3 weeks are the taper period — reduce volume by 40–60% while maintaining intensity to arrive at the start line fully recovered.