Workout Pace Percentage Calculator - from Running Writings (2024)

How to usearrow_upward

i I have a full article on percentage-based training! Check it out here!

Percent of pace vs. percent of speedarrow_upward

There are a few intricacies to calculating percentages; one of these is that percent of speed is not the same things as percent of pace. See the linked article for an in-depth explanation of why.

Renato Canova's workouts all use percentage of pace. This approach has the advantage of being evenly-spaced and symmetric in increments of pace: 90% of 5:00 mile pace is 5:30, and 80% of 5:00 mile pace is 6:00 (i.e. each 10% jump is 30 seconds per mile). Percent of pace is the approach I use with my own training and coaching.

One consequence of the math behind taking percents of pace is that faster speeds are more finely-grained, which makes intuitive sense from a coaching perspective: effort-wise, there's a much bigger difference between 3:00/km and 3:05/km vs. 4:00/km and 4:05/km. Percent of speed works the opposite way: small percentage jumps are very big at high speeds, which is not desirable.

Scientific research typically uses percent of speed because of speed's linear relationship with distance covered per unit time. Percent of speed is evenly-spaced and symmetric in terms of speed (e.g. each 10% jump is an equal increment in miles per hour).

Do note that neither method is symmetric with respect to the reference speed: 120% of 80% of any speed does not return the original speed, regardless of how you define percentages.

Percentages are better than seconds per mile rulesarrow_upward

Percentage-based workout paces have a significant advantage over simple additive rules like "tempo pace equals 5k pace plus 20 seconds per mile." These additive rules fail both for very fast and very slow runners; percentages of pace generalize to a much wider range of abilities.

Forward and backward calculationsarrow_upward

Often, you'll have a workout that goes better than expected: suppose you ran five miles at 90% of 5k pace and had a great day, averaging 5:24/mi even though your plan was to run 5:30/mi. You can switch to "reverse mode" (just click the flip_camera_android icon) to figure out what original pace would've yielded 5:24 at 90%—in this case, it's 4:52/mi.

Unit conversionsarrow_upward

For convenience, I also built in some simple unit conversions. Many of Renato Canova's workouts are kilometer-based, so I like being able to convert to and from miles, kilometers, and (for track workouts) 400m splits.

You'll notice that the percentage calculations are not affected by the unit conversions—this is by design; 90% of 5:00 is 5:30, regardless of whether that's in minutes per mile, minutes per kilometer, or minutes per 400m.

The 5% rule and other useful conversionsarrow_upward

One reason percentages of pace are so convenient is the "5% rule": roughly speaking, a well-trained runner will slow down by 5% for every doubling of race distance. This means that the following approximate race conversions hold:

10k pace is 95% of 5k pace
Half marathon pace is 90% of 5k pace or 95% of 10k pace
Marathon pace is 95% of half marathon pace, 90% of 10k pace, and (very hesitantly) 85% of 5k pace

Additionally, I find the following (again, approximate) physiologically-based markers to be useful for planning workouts:

Critical speed / critical velocity is 95% of 5k pace
Lactate threshold is 91-92% of 5k pace
Aerobic threshold is 85% of 5k pace

Your individual disposition as a runner, and your training status, will of course push these numbers up or down. As an example, with high school runners I almost always use more like 90-91% of 5k pace for lactate threshold because of "aerobic drift" - compared to more experienced runners, high schoolers run the 5k with greater reliance on their glycolytic energy system, and their performance in longer distances is proportionally worse when compared to more experienced runners with the same 5k PR.

Conversely, I work with some marathon runners who, in top condition, can run the marathon only 3-4% slower than their half marathon pace, and who have a lactate threshold closer to 93% of 5k pace.

Suggested percent-based workoutsarrow_upward

Here's a small sample of some of my favorite percentage-based workouts that I use across a wide variety of events:

Event	Type	Session
1500m & up	Aerobic base	8 x 3 min at 91-92% of 5k pace w/ 45-60 sec jog recovery
5k & up	Aerobic base	12 mi long fast run at 80% of 5k pace
800m	Endurance	4-6 x 600m at 80% of 800m pace w/ 1-3 min walk recovery
5k & 10k	Specific	3 sets of: (2 km at 95% of 5k, 1-2 min jog, 1 km at 98-101% 5k) w/ 3-5min jog recovery
Half-marathon	Specific	10 sets of (1 km at 100-102% HMP, 1 km at 88-90% HMP)
Marathon	Endurance	18 mi long fast run at 90% MP

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