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Lactate Threshold Pace Calculator

Threshold pace and heart rate, five training zones, VDOT and race predictions from one race time plus your resting and maximum heart rate. How it works

Use the Lactate Threshold Pace Calculator

Race Distance
Race Time (HH:MM:SS)

Personal metrics

10 to 100; not used in the zones

Not used in the calculation

Threshold pace
7:36 /mi
Threshold HR 173 bpm · VDOT 45.3

The lactate threshold is the effort above which lactate builds up in the blood faster than it is cleared. This page does not measure it: threshold pace is a fixed 88% of the speed your VDOT implies, and threshold heart rate is a fixed 90% of your heart-rate reserve. VDOT comes from your race time using the Daniels and Gilbert formulas. Enter a maximum heart rate you have measured: every heart-rate zone moves with it. No race time? The Target Heart Rate Calculator gives zones from age and resting heart rate alone, with the values above filled in.

Training Zones

Zone 1 - Recovery
HR: 145-155 bpm
Pace: 9:30 /mi – 8:45 /mi
Very easy: recovery runs and warm-ups.
Zone 2 - Aerobic
HR: 155-165 bpm
Pace: 8:45 /mi – 7:59 /mi
Easy, conversational: most weekly miles.
Zone 3 - Tempo
HR: 165-170 bpm
Pace: 7:59 /mi – 7:36 /mi
Steady to comfortably hard, ending at threshold pace.
Zone 4 - Threshold
HR: 170-178 bpm
Pace: 7:36 /mi – 6:41 /mi
Hard. The band runs from threshold pace to 12% faster, and Zone 3 ends where it starts.
Zone 5 - VO2max
HR: 178-185 bpm
Pace: 6:41 /mi – 6:05 /mi
Very hard: short intervals, 12 to 20% faster than threshold pace.

Race Predictions

800 m
2:58
1 Mile
6:22
3K
12:36
5K
21:42
10K
45:00
Half Marathon
1:39:44
Marathon
3:27:15

About the Lactate Threshold Pace Calculator

A 45:00 10K gives a VDOT of 45.3 and a threshold pace of 4:43 per km (7:36 per mile). The calculator turns one race time into VDOT with the Daniels and Gilbert formulas, takes 88% of the matching speed as lactate threshold pace, and sets threshold heart rate at 90% of your heart-rate reserve: 173 bpm for a resting 60 and a maximum of 185.

Threshold pace by race time

Race and timeVDOTThreshold pace per kmThreshold pace per milePredicted marathon
5K in 20:0049.84:227:023:11:17
5K in 25:0038.35:248:423:57:55
5K in 30:0030.86:2610:214:43:39
10K in 40:0051.94:136:483:04:38
10K in 45:0045.34:437:363:27:15
10K in 50:00405:138:243:49:34
10K in 1:00:0032.36:129:594:33:22
Half in 1:30:00514:176:543:07:35
Half in 2:00:0036.55:389:034:07:45

As the calculator shows them, VDOT to one decimal (a whole number shows without one). Heart rate does not change any of these columns.

How to use this tool

  1. Pick the race distance (800 m, 1500 m, 1 mile, 3K, 5K, 10K, 15K, half or marathon) and type the finish time in hours, minutes and seconds. A recent race run flat out gives the most useful VDOT.
  2. Enter your resting and maximum heart rate. Age only has to be between 10 and 100, and gender is not used.
  3. Choose Imperial for minutes per mile or Metric for minutes per km, then read threshold pace, threshold heart rate, VDOT, the five zones and the race predictions for 800 m, 1 mile, 3K, 5K, 10K, half marathon and marathon.
  4. No race time? The link under the result opens the Target Heart Rate Calculator with your age, resting and maximum heart rate filled in, for zones from heart rate alone.

Frequently asked questions

How do I find my lactate threshold pace?
A lab test with blood samples measures it. Without one, a race time gives a usable estimate: this page takes 88% of the speed that matches your VDOT. A 25:00 5K puts threshold pace at 5:24 per km, or 8:42 per mile.
What is VDOT?
Jack Daniels’ name for an “effective VO2max”: the VO2max a runner would need to run the race time you entered, worked out from the oxygen cost of the pace and the share of VO2max that can be held for that long. It is a performance score, not a measurement of your own VO2max in a lab.
Where does threshold pace sit in the pace zones?
The pace bands are multiples of threshold pace per km and follow each other with no gap: Zone 3 runs from 1.05 to 1.00 times it, Zone 4 from 1.00 to 0.88 and Zone 5 from 0.88 to 0.80. Zone 4, the threshold zone, therefore starts at the threshold pace shown at the top and runs to 12% faster, and Zone 3 ends at the same pace.
How is threshold heart rate worked out?
With the Karvonen method: resting heart rate + 0.90 × (maximum − resting). For a resting 60 and a maximum of 185 that is 60 + 0.90 × 125 = 172.5, shown as 173 bpm. The zone edges use 68, 76, 84, 88 and 94% of the same reserve.
How accurate are the race predictions?
Each prediction is the time that gives the same VDOT at the other distance, so the race you entered always predicts itself. The formula does not know your weekly mileage or long runs, so a marathon predicted from a 5K assumes you are as well prepared for 42.2 km as you were for 5 km.

Setting threshold and easy paces from a race

Enter a recent race (800 m, 1500 m, 1 mile, 3K, 5K, 10K, 15K, half or full marathon) with its finish time, plus your resting and maximum heart rate. The tool returns a threshold pace, a threshold heart rate, five pace and heart-rate zones, and race predictions. Use it to set the pace of a 20-minute tempo run or 3 × 10 minute cruise intervals.

With a 45:00 10K and heart rates of 60 and 185 bpm, VDOT is 45.3, threshold pace is 4:43 per km (7:36 per mile) and threshold heart rate 173 bpm. The predictions give the same 45:00 10K back, with 800 m in 2:58, a mile in 6:22, 3K in 12:36, a 5K of 21:42, a half marathon of 1:39:44 and a marathon of 3:27:15. With no race time, the link under the result opens the Target Heart Rate Calculator with your heart rates filled in.

How threshold pace and the zones are set

VO2 = −4.60 + 0.182258 × v + 0.000104 × v², with v your race speed in metres per minute, is Daniels and Gilbert's oxygen cost of running. VDOT = VO2 ÷ (0.8 + 0.1894393 × e^(−0.012778 × t) + 0.2989558 × e^(−0.1932605 × t)), with t the race time in minutes, divides it by the share of VO2max held for that long. The result is clamped to 15–85. Threshold pace is 88% of the speed whose oxygen cost equals the VDOT. Heart rates use the Karvonen method, resting + (max − resting) × %, with 90% as threshold and zone edges at 68, 76, 84, 88 and 94%.

For the 45:00 10K, the speed is 222.2 m/min, the oxygen cost 41.04 and the sustainable share 0.9066, so VDOT is 45.3. Race predictions find the time at which each distance gives that same VDOT, so the race you entered predicts itself unless VDOT was clamped. Sex changes nothing; age must be 10 to 100.

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