Free Training Pace Calculator for Ultras¶
The free training pace calculator does one job. You give it a distance and a finish time from a race you already ran, and it hands back a VDOT score plus five paces: Easy, Marathon, Threshold, Interval, and Repetition. No account, no card, nothing to install.
Open the training pace calculator
Then there is the part that gets left off most pace-zone pages. Those five zones were worked out on road races, on flat ground, where pace is a fair measure of how hard you are working. Out here it often is not. A pace number on a twenty percent climb tells you almost nothing about the effort you just spent.
So this post covers three things: what the calculator gives you, which race to type into it, and where the numbers stop describing your day.
What you type in, and what comes back¶
Two inputs. That is the whole form.
- A recent race distance. 5K, 10K, half marathon, marathon, 50K, 50 mile, 100K, 100 mile, or a custom distance in miles.
- The finish time, in hours, minutes, and seconds.
What comes back is a VDOT score and a table of five paces per mile, each with a line saying what it is for. There is a chart of the five, an image you can save, and a box to email the results to yourself so they are on your phone at the trailhead.
Here is what it returns for a 24:00 5K, which comes out at VDOT 40.1:
| Zone | Pace | What it is for |
|---|---|---|
| Easy | 11:14/mi | Recovery and long runs at a conversational effort |
| Marathon | 8:29/mi | Steady marathon-goal effort |
| Threshold | 8:11/mi | Comfortably hard tempo and cruise intervals |
| Interval | 7:32/mi | Hard three to five minute reps |
| Repetition | 7:06/mi | Short, fast reps for speed and economy |
If you want the five zones explained properly, Training Paces Explained walks through what each one trains and why most of your week belongs in Easy. This post assumes you have that and goes at the calculator itself.
Which race to type into the free training pace calculator¶
Short version: the shortest race you have run honestly in the last few months.
That sounds backwards when you are training for a hundred. It is worth seeing why, because the same tool will take your hundred-mile finish and give you back a number, and the number will look reasonable.
VDOT works by fitting a curve to the oxygen cost of running at a given speed, then adjusting for how long you held that speed. The adjustment fades out fast. Past about four hours the equation treats every effort as roughly the same fraction of your aerobic capacity, whether it lasted four hours or twenty-four. It also assumes you ran the whole thing. A hundred-mile finish includes the climbs you hiked, the aid stations, the night, and the hour at mile seventy when you were sorting yourself out. All of that is in the average.
Same runner, same year, three different things typed into the same calculator:
| What you type in | VDOT it returns | Easy | Interval |
|---|---|---|---|
| 5K, 24:00 | 40.1 | 11:14/mi | 7:32/mi |
| 50K, 7:00 | 23.2 | 16:55/mi | 11:38/mi |
| 100 miles, 28:00 | 17.3 | 20:41/mi | 14:32/mi |
None of those rows is a bug. The bottom row is an accurate average of a hundred-mile day, and knowing your all-day moving average is useful for other things, like predicting a finish time. It is just not a training pace. Look at the interval column: 14:32 per mile is not an interval, it is a fast hike.
The short race is the input that comes closest to measuring what the model is trying to measure, which is how fast you can move when nothing else is in the way. So use the 5K or the 10K if you have one. A half marathon works. A road marathon works. Feed it the mountain hundred and you get a portrait of the mountain, not of you.
If you have not raced anything short in a year, you have two options and neither is wrong. Run a hard, controlled effort on flat ground and use that. Or type in your best guess, take the Easy number, and check it against what your own easy runs have been doing. Your training log is the better authority anyway.
How to find your easy pace¶
Easy is the number that matters most, because it is where most of your week goes.
The calculator gives you a pace. Two things to know about it:
It is a ceiling, not a target. Slower than the Easy number is still Easy. There is no lower bound where the aerobic work stops counting.
It is a flat-ground ceiling. On rolling singletrack, on a climb, on a hot afternoon, at altitude, or on tired legs from Saturday, the same effort produces a slower pace. That is the terrain doing its job, and it is not a fall in fitness.
Most runners find the Easy number slower than what they have been running on easy days. That is normal enough to be the default. It is worth checking against effort rather than taking it on faith: if you can hold a full sentence without reaching for breath, you are in the right place, whatever the watch says.
The heart rate version of this same question has its own problems, and they are worth knowing about before you trade one number for the other. Your Zone 2 Ceiling Is Wrong covers how far off a formula-derived zone can be.
Ultra training paces, translated¶
Here is what each of the five is worth once the training is for a trail race.
| Zone | Where it transfers | Where it stops |
|---|---|---|
| Easy | The most useful of the five. Most of your week. | Any sustained climb. The number goes quiet. |
| Marathon | The runnable flat sections of a fast 50K or a road-ish ultra. | A mountain hundred, where nothing is held that steadily. |
| Threshold | Keeps its value at every distance. Raising the point where fatigue starts cascading pays off at mile eighty too. | Technical footing. Run it where the ground lets you hold a pace. |
| Interval | Honest on a track or a flat path. Three to five minute reps. | Grade. On a steep pitch there is no pace that corresponds. |
| Repetition | Form and economy work, on flat ground. | Same as Interval, plus it is the first thing to drop in a high-volume block. |
The pattern across all five: the paces are honest on ground where pace is honest. The further the terrain gets from a track, the more the number becomes a rough guide and the more your own effort has to carry the session.
For the vertical side of the same problem, Power Hiking for Ultras and Trail vs Road Running Pace go further than this post does.
When the ground goes up, the pace number goes quiet¶
This is the thing that pace-zone content usually leaves out.
On a steep climb, pace and effort come apart completely. Hiking a twenty percent grade can cost more per minute than running flat, and it can show up on your watch as an eighteen minute mile. The mile is not the story. The grade is.
Grade-adjusted pace models exist, and every platform has one. They disagree with each other, they were mostly built on road and light-trail data, and none of them knows what your legs did on that climb. Feeding one of those adjusted numbers back into a road pace zone stacks one estimate on top of another.
What holds up instead:
- Effort. The talk test still works on a climb, and it does not care about grade.
- Time. A three-hour climb-heavy day is a three-hour day, whatever the average pace says. Time on feet over pace. Time on Feet vs Mileage makes the case in full.
- Your own record. What your heart rate and your effort did on that same climb six weeks ago is a better reference than any formula, because it is you, on that ground.
None of this makes the calculator less useful. It puts it in the right place: it is a good answer for flat runnable miles, and it is quiet about the rest, which is honest of it.
What the calculator cannot know¶
Worth saying plainly, because a number in a box tends to look more certain than it is.
- It does not know the terrain, the vert, the heat, or the altitude. It does arithmetic on the two things you typed.
- It does not know whether that race was a good day. A day you were sick, or the day everything clicked, both go in as the same kind of fact.
- It does not know that eight weeks have passed. One race is a snapshot, accurate on the day you ran it. Fitness moves in both directions.
- It is not precise to the second. The zone intensities behind those five numbers are approximations of Daniels' published values, set so the paces come out in the right order and in a sensible range. Read them to the nearest fifteen seconds and you will be inside the model's real accuracy.
That last one matters more than it sounds. Chasing 11:14 when the model means "somewhere around 11:15" turns a useful guide into a thing to fail at.
Using it this week¶
- Type in your shortest honest race from the last few months.
- Round the paces to the nearest fifteen seconds and write down the Easy and Threshold numbers. Those two carry most of the week.
- Use the Easy number as a flat-ground ceiling. Anywhere with real climb, run by effort and let the pace be whatever it is.
- Put the Threshold session where the ground is runnable. Flat trail, road, or track. The point is holding the effort, and technical footing gets in the way of that.
- Re-run it after your next race. The paces are only current as long as the race behind them is.
Get your paces from the free training pace calculator
Questions¶
Is the training pace calculator free?¶
Yes. No account, no card, no email required to see your results. Enter one race and the paces come back on the page. There is an optional box to email them to yourself if you want them on your phone, and that is the only place an address is asked for.
What is VDOT?¶
VDOT is Jack Daniels' single number for your current running fitness, worked out from one race result. One VDOT sets all five training paces at once, in proportion to each other. Training Paces Explained has the longer version.
Can I use a 50K or 100-mile finish time?¶
You can, and the calculator will take it. Just know what comes back. A long mountain finish includes hiking, aid stations, and the night, so the paces it returns describe that day rather than your aerobic ceiling. A 5K, 10K, or half gives the model the kind of input it was built on.
Why is my easy pace so slow?¶
It is supposed to feel easy. Most of your weekly mileage sits there so you recover and keep building the aerobic side. If the number looks slow next to what you have been running, that is common, and it is information rather than a verdict.
Do these paces work on trail?¶
Partly. Easy and Threshold transfer as efforts. The pace numbers themselves hold on flat runnable ground and stop meaning much once there is real vertical. On a climb, use effort and time instead.
Is this the same as a free running training zones calculator based on heart rate?¶
No. These zones come from a race result and are expressed in minutes per mile. Heart rate zones come from your own heart rate data, and they have their own accuracy problem worth reading about in Your Zone 2 Ceiling Is Wrong. The two can be used side by side. Neither is the boss of the other.
What if I have not raced in a year?¶
Type in your best recent hard effort and treat the output as a starting guess. Then check it against your own runs over the next two weeks. Your log is a better source than a race from last summer.
Start with the calculator¶
The calculator does arithmetic on one race. That is its strength and its whole limit: it is fast, it costs nothing, and it has no idea what you have been doing since.
That gap is what NavRun works on. Connect Strava and it reads the running you already logged, the long runs, the vert, the weeks that were heavy and the weeks that were not, and keeps your paces current as your fitness moves. Getting a training plan costs nothing.
Start with the pace calculator. If you want paces that stay honest week to week, connect Strava and let your own record set them.