Quick answer: Enter a recent race time and distance below. The calculator applies StrideIQ’s RPI equations to derive your Running Performance Index (RPI) — your current aerobic fitness score — and outputs your five training pace zones in both min/mile and min/km.
The calculator uses StrideIQ's RPI equations, a measure of your current aerobic capacity derived from race performance rather than a lab test. StrideIQ expresses the result as an RPI (Running Performance Index) score.
Your race time and distance are converted to an RPI score. Each RPI score maps to five training intensity zones: Easy (E), Marathon (M), Threshold (T), Interval (I), and Repetition (R). These zones correspond to distinct physiological targets — aerobic base building, lactate threshold development, VO2max stimulus, and neuromuscular speed.
The Easy pace range is wide intentionally — it's the zone for most of your weekly volume. Running too fast on easy days is the most common training mistake. The Threshold pace (tempo pace) should feel comfortably hard — you could hold it for 20 minutes in a race but not much longer. Interval pace is close to your 3K–5K race pace.
For marathon and half marathon training specifically, your Marathon pace zone is the most important: it's the effort you need to sustain for 2–5 hours. Most runners train their marathon pace too fast in training and pay for it on race day.
See complete pace tables for common race times at each distance — no calculator needed.
See the exact easy, threshold, interval, and marathon training paces for your goal time — no calculator needed.
Use your most recent race result from the past 3–6 months. A 5K or 10K gives the most accurate current fitness picture. Older or longer races may underestimate your current fitness if you've been training consistently.
Easy pace (60–79% effort) builds aerobic base with minimal fatigue. Threshold pace (83–88% effort) is your comfortably hard tempo run pace — sustainable for 20–40 minutes. Interval pace (95–100% effort) builds VO2max in short, hard repeats with rest between.
After each significant race or time trial that reflects your current fitness — typically every 4–12 weeks of consistent training. Don't update based on a bad race day; wait for a performance that feels representative of your current shape.