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Tempo Pace Calculator Race Time to Tempo, Critical Velocity, and Sub-Threshold Pace

Let's face it — most tempo pace calculators hand you one number and leave you to work out what it actually means. I've coached threshold sessions for over twenty years, and a single figure with no context is only ever half the answer.

Here's the principle before the calculator: tempo pace — also called lactate threshold pace — is derived from your current fitness, best proxied by a recent race result. It isn't a fixed number, and it isn't the same for every runner at a given ability. As a starting formula, back-of-pack runners run tempo pace at roughly their current 10K pace plus 15 to 20 seconds per kilometre; mid-pack runners at roughly their 15K-to-half-marathon pace; faster runners at close to straight half-marathon pace. This is the same formula used on the main tempo running guide, and the calculator below turns it into an exact number from your own time — plus the two paces either side of it that most tools never mention.

The Calculator: Enter Your Race Time, Get Three Paces

A single tempo number isn't the full picture. This calculator gives you three, all built from one consistent pace-derivation method — the same one behind the site's general training pace calculator and the tempo running guide's own race-time table — so none of BRT's tools quietly disagree with each other.

If your only recent result is at a different distance, convert your race time to another distance first, then come back and enter it below.

Tempo Pace Calculator Enter a recent race performance below — ideally a 10K to half marathon.
Race distance		KilometresMiles
Finish time		: : (hh:mm:ss)
Sub-Threshold Pace
Tempo / Threshold Pace
Critical Velocity

Tempo, Critical Velocity, and Sub-Threshold — What Each Pace Is For

Three numbers, three different jobs. Here's the boundary between each, in plain terms.

Sub-threshold pace (also called extensive tempo) is comfortably hard — sustainable well beyond an hour. I use it for longer continuous tempo runs and marathon-specific work. Lactate is still being cleared with room to spare, so this is the pace you can hold the longest of the three.

Tempo pace, or threshold pace, is the edge itself — sustainable for roughly 60 minutes at true race effort. It's the pace at which lactate production and clearance are in near-balance, and that balance point is exactly why it's trainable and why it moves as your fitness does.

Critical velocity sits above threshold, sustainable for only 20 to 30 minutes. Past this point lactate accumulates faster than your body clears it, so critical-velocity work gets dosed in shorter, broken efforts — never one continuous run at this pace.

A quick way to tell them apart mid-run, by feel alone: sub-threshold is comfortably hard, and you could hold a short conversation. Tempo is hard, short phrases only. Critical velocity is very hard, single words.

Which Formula Is Behind the Numbers

Every tempo pace tool I've checked outputs a number with no stated methodology. That's the gap this section closes. Three formula families produce a "tempo pace" figure, and they're not interchangeable:

This calculator deliberately uses race-time regression. It needs only a result you already have, at accuracy that's more than sufficient for training-pace purposes — I'd rather be upfront about that trade-off than let the number pretend to be more precise than it is.

No Recent Race? How to Estimate Instead

No result on the books? You've got two practical routes.

The first is a genuine time trial: an all-out effort over 3K to 5K on a flat, familiar route, used exactly the way a race result would be. The second, if a time trial genuinely isn't possible, is your current easy pace and perceived effort combined with your training age — a rough placeholder, not a precise input.

Beware: an estimate that's off in either direction throws out all three paces, not just tempo. Replace it with a real result within 4 to 6 weeks.

Adjusting Your Paces for Heat, Hills, Altitude, and Treadmill

No calculator I've come across addresses anything beyond a flat, temperate outdoor run. Here are the adjustments I coach to — rules of thumb, not lab constants:

These are adjustments for conditions on the day, not for age or long-term fitness change — for that, see tempo pacing by age and fitness level.

How These Paces Fit Into a Workout

Three numbers on their own don't tell you how to use them. Here's how each one gets deployed:

Sub-threshold pace — continuous runs of 30 to 60-plus minutes, or blended into long-run segments.

Tempo pace — the core session types from the tempo running guide: mile repeats, longer intervals, continuous 20 to 30 minute efforts.

Critical velocity — shorter broken intervals only, at the harder end of what the anchor guide calls "longer tempo intervals." Never a continuous effort at this pace.

For how session structure builds across a full block, see the 8-week tempo progression plan.

When and How Often to Recalculate

None of these three paces are one-time numbers. Recalculate after any new race or genuine time trial. As a default, revisit them every 6 to 8 weeks through a structured training block, even without a race — fitness shifts faster than most runners re-check their figures.

Here's the practical trigger for recalculating early rather than waiting for the calendar: if tempo-pace sessions consistently feel like sub-threshold effort rather than hard, short-phrases-only breathing, that's your signal — not a fixed date. See fitting tempo runs into your week and the 8-week tempo progression plan for how pace changes get built into a training block rather than adjusted mid-week.

Get your number, know what it's for, and recalculate before it goes stale — that's a sensible way to train. Head back to the full tempo running guide for the complete workout library.

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