VDOT Calculator

This VDOT calculator turns one race time into a VDOT, five training paces and equivalent times from 1500 m to the marathon. It uses the equations Jack Daniels and Jimmy Gilbert published in 1979. You can add a second race to see which result counts, and a goal time to see the VDOT it needs. The working is shown, and where our training paces differ from the official tables, the VDOT calculator says so on screen.

About the VDOT calculator

VDOT is a fitness number you get from a race, not a lab. Run 5K in 22:30 and your VDOT is 43.4. That one number then sets your training paces and tells you what the same fitness is worth over 10K or a marathon.

Most calculators take one race and stop. This one answers three more questions.

• Which of my races counts? Enter two. You see the VDOT from each, and the paces use the higher one.
• What do I need for my goal? Enter a goal time. You see the VDOT it takes, how many points away you are, and what you’d run today.
• Where does the number come from? Open “Show the working” and the two equations are filled in with your own speed and time.
• Can I trust the training paces? From VDOT 40 up, they match the official calculator to within two seconds a mile. Below 39 they don’t, and the tool tells you.

It runs in your browser. Nothing you type is stored or sent anywhere.

How to use the VDOT calculator

1. Pick the distance of a recent race. There are nine standard distances, or choose “Other distance” for anything from 1 km to 50 km.
2. Type your time. Write 22:30 for minutes and seconds, or 1:43:27 for hours, minutes and seconds.
3. Read the VDOT and the four boxes. Easy, Marathon, Threshold and Interval pace, per mile, with the per-kilometre figure underneath.
4. Add a second race or a goal if you want. Both are optional. Leave the time empty and they’re ignored.

Use a race you ran hard, within the last four to six weeks, on a flat course in decent weather. A hilly trail race or a hot day gives a VDOT lower than your real fitness.

The formula behind the VDOT calculator

Two equations, both from Daniels and Gilbert’s Oxygen Power (1979).

The first is the oxygen cost of running at a speed v, in metres a minute:

VO2 = -4.60 + 0.182258 × v + 0.000104 × v²

The second is the share of your maximum you can hold for a race lasting t minutes:

share = 0.8 + 0.1894393 × e^(-0.012778 × t) + 0.2989558 × e^(-0.1932605 × t)

Divide one by the other:

VDOT = VO2 ÷ share

The idea is simple. A short race is run close to your maximum. A long one is run at a lower share of it. The second equation says how much lower. A 12-minute race sits at about 99%. A marathon sits near 80%.

To get an equivalent time at another distance, the VDOT calculator searches for the time that gives the same VDOT. There is exactly one, because VDOT falls steadily as the time gets longer.

A worked example

You run 5K in 22:30.

1. Speed. 5,000 m in 22.5 minutes is 222.2 metres a minute.
2. Oxygen cost. -4.60 + 0.182258 × 222.2 + 0.000104 × 222.2² = 41.04.
3. Share. For 22.5 minutes the second equation gives 0.946.
4. VDOT. 41.04 ÷ 0.946 = 43.4.

From 43.4 you get:

And equivalent times of 46:40 for 10K, 1:43:27 for the half marathon and 3:34:43 for the marathon.

VDOT chart: race times and training paces

Every figure below comes from the same equations as the tool. Race times are equivalents. Paces are per mile, except Repetition, which is per 400 m.

The race times agree with the table in Daniels’ Running Formula to within 0.2%. For rows 30 and 35, read the note on slower runners below before you use the training paces.

What the five paces are for

Daniels gives each pace a job. The summary below follows his descriptions.

Easy (E)

Warm-ups, cool-downs, recovery days and most long runs. It should feel like you could talk. Most of your weekly distance belongs here. The range is wide on purpose: the slow end is fine when you’re tired or it’s hot.

Marathon (M)

The pace of your equivalent marathon. It’s for marathon training, as steady runs or long repeats. If you’ve never trained for a marathon, read it as a training pace and not a promise.

Threshold (T)

“Comfortably hard”. A pace you could race for about an hour. Run it as a steady 20-minute tempo, or as cruise intervals: repeats of several minutes with short rests. Daniels caps it at about 10% of weekly distance.

Interval (I)

Hard, at the effort where you’re working close to your maximum oxygen uptake. Repeats of three to five minutes with a jog recovery a little shorter than the repeat. Daniels caps it at about 8% of weekly distance.

Repetition (R)

Fast and short: 200 m, 300 m or 400 m with full recovery. It’s for speed and economy, not for breathing hard. Daniels caps it at about 5% of weekly distance.

The usual mistake is running every pace too fast. A faster Threshold run is not a better one. To earn faster paces, race faster and enter the new time.

Two races, two numbers

Few runners get the same VDOT from every distance. Say you ran 5K in 22:30 and 10K in 48:30. The 5K gives 43.4 and the 10K gives 41.5. Which do you train from?

Daniels’ advice is the higher one, and that’s what the VDOT calculator does. It also tells you the size of the gap, because the gap means something.

• Under one point. Normal. Call them the same.
• One to two points. Common. One race had a better day, or suits you better.
• Two or more. Look for a reason. A hilly course, heat, a bad start, or a distance you haven’t trained for.

A pattern across several races is worth noticing. If your short races always give the higher VDOT, you have speed and need endurance. If the long ones do, it’s the other way round.

Checking a goal time

Enter the time you want and the distance in the third box of the VDOT calculator. The same 22:30 5K runner asks about a 3:30:00 marathon:

• A 3:30:00 marathon needs a VDOT of 44.6.
• They’re at 43.4, so the goal is 1.2 points away.
• Their fitness is worth 3:34:43 today. The goal is 4:43 faster.

That turns a vague hope into a number. Around VDOT 45, one point is about 24 seconds over 5K. So this runner needs to bring the 5K down to roughly 22:00 and do the marathon training on top.

If the goal needs a lower VDOT than you have, the tool says you’re already there and shows what your fitness is worth at that distance.

Choosing the race to enter

The VDOT calculator can only be as good as the race you give it. A few rules make the number more useful.

• Recent beats fast. A personal best from three years ago describes a runner you used to be. Use a result from the last month or two.
• All-out beats comfortable. A race you jogged with a friend gives a VDOT well below your fitness. If you haven’t raced, run a time trial on a track and treat it as one.
• Flat and cool beats hilly and hot. The equations assume a fair course. They can’t know about the hill at mile two.
• Measured beats estimated. A certified road course or a track is best. A watch that read 3.02 miles for a 5K has changed your pace by a few seconds a mile.
• Middle distances are the safest. A 5K or 10K suits most runners. A mile leans on speed. A marathon leans on fuelling, pacing and the weather on one day.

If you have nothing recent, enter what you have and treat the paces as a starting point. Run a couple of Threshold sessions. If they feel easy at the right pace, you’re fitter than the old race says.

Using the paces on a track

The training table gives Threshold, Interval and Repetition pace per 400 m, which is one lap of a standard outdoor track. That’s the number to use for workouts measured in laps.

Take the 43.4 example. Interval pace is 1:45 per lap. An 800 m repeat is two laps, so 3:30. A 1,200 m repeat is three, so 5:15. Repetition pace is 1:39 per lap and 0:50 for 200 m.

Round to the second and don’t chase the watch on every lap. A lap two seconds fast followed by one two seconds slow is still the right session. Ten laps all four seconds fast is a different session, and a harder one than the plan asked for.

On the road, use the per-mile or per-kilometre column and accept more drift. Hills, corners and wind move a mile split by more than the difference between two VDOT points.

When to update your VDOT

Your VDOT should change when your racing does. Daniels’ approach is to train at the paces your last race earned until a new race earns faster ones.

• After a race that gives a higher number. Enter it in the VDOT calculator and move to the new paces.
• After several weeks when the paces feel clearly easier. Some runners move up by one point, then confirm it with a race when they can.
• After time off. Fitness drops with a layoff. Come back at a lower number and let a race or time trial reset it.

Don’t raise it because one session went well. One good Tuesday is not a fitness change.

Common mistakes

• Typing minutes as hours. 22:30 is twenty-two and a half minutes. 22:30:00 is most of a day. The tool rejects speeds past the world record or slower than a walk, which catches most slips.
• Using a goal time as the race. Your paces come from what you’ve run, not what you hope to run. Put the hope in the goal box.
• Reading the marathon time as a forecast. It’s what your fitness is worth with marathon training behind it.
• Running Easy pace at the fast end every day. The range is there to be used.
• Comparing VDOT with a watch’s VO2max. They’re estimated differently and rarely match. Compare each with its own past values.

A note for slower runners

This matters if your VDOT is under 39, which is a 5K slower than about 24:40.

We set training paces as fixed shares of VDOT: 88% for Threshold, 97.5% for Interval. From VDOT 40 to 60 that reproduces the official calculator to within two seconds a mile. We checked on October 11, 2026.

Below 39 the official tables go faster than the fixed shares do. At VDOT 30 the official Threshold pace is 9:55 a mile. Ours is 10:18. The Interval gap is bigger: 8:49 against 9:30.

We don’t know the adjustment the official tables use, and we haven’t guessed at one. So under VDOT 39 the VDOT calculator shows a note. Your VDOT and your equivalent race times are unaffected. Treat our training paces as the gentle end, and check them against the official calculator at vdoto2.com.

What a VDOT can’t tell you

• It isn’t your VO2max. A lab measures oxygen. VDOT measures performance. A very economical runner has a VDOT higher than their lab number, and that’s the point of it.
• Equivalent isn’t predicted. The marathon time assumes marathon training. Most runners who enter a 5K time run slower than the marathon figure shown.
• Conditions aren’t included. There’s no heat, altitude, wind or hill adjustment here. We don’t have a verified formula for any of them, so we left them out.
• Very short and very long races stretch it. The equations were built on races from a few minutes to a few hours. Under three and a half minutes or over five hours, the tool warns you.
• It’s a training guide, not medical advice. If you’re new to hard running or have a health condition, talk to a doctor before interval work.

Related calculators

For military fitness tests, the PFT calculator scores the Marine Corps run, pull-ups and plank. Lifters can compare totals with the DOTS calculator. Cyclists can set pressures with the bike tire pressure calculator. To count the weeks to race day, use the date duration calculator.

VDOT is a trademark of The Run SMART Project. FreeToolBank isn’t affiliated with it, with Jack Daniels or with VDOT O2. This VDOT calculator uses the published equations and names its own assumptions.