Free tool
Norwegian Singles
pace calculator.
Enter a recent race result and get your VDOT, training paces, heart-rate zones, and three ready-made threshold workouts — the short, medium, and long sessions most runners on the Norwegian single-threshold protocol rotate through each week.
Your race result
Use a race within the last 4–8 weeks for the most accurate paces.
Adjust for conditions
Temperature, humidity, and altitude affect sustainable pace.
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Adjust for conditions
Temperature, humidity, and altitude affect sustainable pace.
Training paces
| Easy | 5:44 – 5:14/km |
| Long run | 5:29 – 4:59/km |
| Threshold | 4:14/km |
| Interval (VO2max) | 3:54/km |
| Repetition | 3:39/km |
| Recovery | 5:59/km |
Heart-rate zones
Enter your max HR above to see BPM targets.
| Zone | % of max |
|---|---|
| Z1 — Recovery | 0–65% |
| Z2 — Easy Aerobic | 65–78% |
| Z3 — Threshold / Tempo | 78–88% |
| Z4 — VO2max | 88–95% |
| Z5 — Anaerobic / Sprint | 95–100% |
This week's workouts
Rotate through these three sessions across your threshold days. Warm up 15–20 min easy, cool down 10 min easy.
Race time predictions
Equivalent efforts at your current fitness. Treat as upper-bound estimates — longer races require specific preparation.
| 1500 m | 5:25 |
| Mile | 5:51 |
| 10 km | 41:28 |
| Half marathon | 1:31:50 |
| Marathon | 3:11:17 |
How this calculator works
The calculator derives your VDOT — an effort index popularised by Jack Daniels — from the race time you enter, then computes training paces using the published Norwegian-method zones. The threshold pace lands in the 2.3–3.0 mmol/L Golden Zone the method targets.
The three suggested workouts — short (10 × 1 km), medium (5 × 6 min), and long (3 × 3 km) — are the canonical single-threshold rotation. Each rep's pace is adjusted for its duration, per the Marius Bakken book: 3 min reps run 5–7 sec/km faster than threshold, 10 min reps 5–7 sec/km slower, and so on.
All calculations run in your browser. Nothing is stored and no account is needed. If you want a full training plan that evolves week-to-week, uses these same paces, and adapts to your actual training data, build one here.
What is the Norwegian Singles Method?
A simpler adaptation of the Norwegian threshold system made popular by Marius Bakken and used by the Ingebrigtsen family. Instead of the elite double-threshold pattern (two threshold sessions on the same day), runners do two to three single sub-threshold sessions a week — typically Tuesday, Thursday, Saturday — plus an easy long run on Sunday.
The defining discipline is intensity control: every rep sits just below lactate threshold, at roughly 80–87% of max heart rate or 15–30 sec/km slower than 5K race pace. Sessions should feel repeatable, not heroic. If you finish wrecked, you ran them too hard.
Expect 4–8 weeks of visible plateau before the first breakthrough. The work compounds. Read the full method page.
Questions
What is VDOT and how is it calculated?
VDOT is Jack Daniels' race-equivalence index — a single number that captures your current aerobic fitness. Enter a recent race result and the calculator derives it with Daniels' published formula, then scales training paces from there.
What's Critical Speed?
Critical Speed (CS) is the theoretical asymptote of sustainable running velocity, derived from two all-out efforts at different distances. The paired CS + D' model fits middle-distance and sub-elite runners particularly well — often tighter than VDOT when your race history is two time trials rather than one longer race.
Why a Norwegian Singles calculator specifically?
The Norwegian Singles method — popularized by the r/NorwegianSinglesRun community with a foreword by Marius Bakken — uses three sub-threshold sessions per week instead of the elite doubles protocol. The calculator's suggested workouts rotate through the canonical Short (10x1km), Medium (5x6min), and Long (3x3km) templates at the correct threshold-adjusted paces.
What are environmental pace adjustments?
Temperature, humidity (via dew point), and altitude all reduce sustainable running speed. The calculator lets you input conditions and shows adjusted paces that preserve the same physiological effort — matching the approach used by LacTrace and sweetspot.run.
Is this a free alternative to sweetspot.run or TrainAsONE?
Yes, the calculator is free and runs entirely in your browser — nothing is stored or sent anywhere. Threshold's paid product is a full adaptive training plan built on the same methodology, with coaching chat and HealthKit integration.
How accurate are the race-time predictions?
Predictions are based on Daniels' VDOT tables or the two-point Critical Speed model. They are generally within 2-3% for distances close to your input race and become less accurate for very different distances (e.g. predicting a marathon from a 1500m). Use them as upper-bound estimates.