Critical Velocity Calculator
This critical velocity calculator implements two models side by side. The two-point critical speed model is the physiology standard: from two all-out efforts it computes CS = (D2 − D1) ÷ (T2 − T1) and D′ (anaerobic distance capacity) = D1 − CS × T1, then predicts time for any distance via T = (D − D′) ÷ CS, valid for roughly 2–30 minute efforts. The Tinman/Schwartz estimate is the popular single-race shortcut: CV velocity = 5K velocity × 0.9533, i.e. CV pace is your 5K pace divided by 0.9533 — a slightly slower pace used for CV repeats.
Model 1: Critical Speed from Two All-Out Efforts
Enter two recent all-out efforts between roughly 2 and 30 minutes (e.g. a 1200m time trial and a 3200m race).Add two times above and your critical speed, anaerobic reserve, and race predictions appear instantly. Or start from an example:
CS = (D2 − D1) ÷ (T2 − T1) · D′ = D1 − CS × T1
(two-point linear distance–time model; predictions use T = (D − D′) ÷ CS)Model 2: Tinman CV Estimate from a 5K
A single recent 5K is enough for a quick critical-velocity estimate — slightly slower than 5K race pace.CV velocity = 5K velocity × 0.9533
(Tinman/Schwartz convention — CV pace = 5K pace ÷ 0.9533)The two-point model is the deterministic physiology standard: CS is the slope of the distance–time line and D′ is its intercept (your anaerobic distance reserve). Use efforts between ~2 and ~30 minutes; predictions outside that window are unreliable. The Tinman estimate is a convenient single-race shortcut — CV reps are typically run at that pace for 3–10 minute repeats.
How coaches use the critical velocity calculator
Use this CV pace calculator when you want critical speed and D′ from two race efforts, a Tinman-style CV pace from a recent 5K, or 400m rep targets for CV workouts.
- Compute critical speed and D′ from a 1200m time trial plus a 3200m race to anchor training zones.
- Set CV rep paces (per mile, per km, per 400m) for 3–10 minute repeats.
- Get a quick Tinman CV pace from a recent 5K when only one race result is available.
- Predict steady-state race times for 2–30 minute events from the CS model.
Critical Velocity Calculator FAQ
Roughly your 5K pace divided by 0.9533 in the Tinman convention — for a 20:00 5K (6:26/mile) that is about 6:45/mile. CV reps are typically 3–10 minutes long (1000m–2000m for most high schoolers) with short recoveries.
Take two all-out efforts between about 2 and 30 minutes. CS is the slope: (distance2 − distance1) ÷ (time2 − time1) in meters per second. D′ is the intercept: distance1 − CS × time1. The further apart the two durations, the more reliable the fit.
D′ is your anaerobic distance reserve in meters — the finite distance you can cover above critical speed before exhaustion. A typical trained distance runner sits around 150–300m. Bigger D′ means a stronger kick; bigger CS means a higher sustainable cruising speed.
Close but not identical. CV/CS sits slightly faster than classic lactate threshold — between threshold and 10K effort for most runners. Tinman-style CV reps target that zone to build aerobic power without the cost of VO2max sessions.
The linear distance-time model assumes the effort is long enough that pure sprint mechanics don't dominate and short enough that fueling, thermoregulation, and durability don't. Outside roughly 2–30 minutes the line bends, so predictions (like a marathon from CS) become unreliable.
If you have two honest all-out efforts at different durations, the two-point model is personalized and more precise. If you only have one recent 5K, the Tinman estimate is a solid default — the two usually land within a few seconds per mile of each other.
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