Virtual Race Pace Calculator

From easy pace to race pace

Feed it your easy-training pace and it estimates what you could hold over 5K, 10K, the half-marathon and the full marathon. The math behind it stays deliberately simple: race_pace = easy_pace · factor, where the factors run 0.85 (5K), 0.88 (10K), 0.92 (half) and 0.96 (marathon). The pattern is intuitive once you see it. As the distance grows, your race pace drifts back toward the conversational shuffle you do on recovery days. Say your easy pace sits at 6:00 min/km. The tool projects a 5K at 5:06/km (~25:30), a 10K at 5:17/km (~52:48), a half at 5:31/km (~1:56:30) and a marathon at 5:46/km (~4:03:00). The ratios land close to what Jack Daniels' VDOT and Garmin Coach assume for runners logging 4 to 5 sessions a week.

Applications and context

Runners reach for it when mapping out an 80/20 polarized block, when setting goals they can actually defend, or when trying to line up treadmill work against what they run on the road. The treadmill comparison deserves care. A 1% incline roughly cancels out the missing air resistance (Mark Allen / Jones & Doust, 1996), and every additional 1% of grade tacks on something like 12–15 s/km to your equivalent pace. That's the logic behind Strava's Grade Adjusted Pace (GAP). Apply those corrections first, then enter the treadmill figure as your "easy pace" here.

FAQ

Are projected paces guaranteed? No. They lean on a solid aerobic base and proper marathon-specific long runs. If your weekly volume stays under 50 km, expect the marathon number in particular to read a touch optimistic.

What defines an "easy pace"? It's the pace you can hold while chatting, roughly 70% of HR max, somewhere around 1.5 to 2.0 min/km slower than your 5K race pace. The talk test is the giveaway. If full sentences are a struggle, you've drifted too fast.

How do I adjust for hills or treadmill? For uphills, add about 12 s/km for each 1% of average grade, or just lean on Strava's GAP. Indoors, a 1% incline gets the effort closer to what you'd feel outside.