Beep test calculator

Turn the level you reached on the 20-metre multistage shuttle run into a VO2 max estimate (Léger 1988) and your maximal aerobic speed — and see why the formula holds adult age at 18, which most beep test calculators get wrong.

How the math works

The 20-metre multistage shuttle run — the beep test, bleep test, or PACER — has you run back and forth between two lines 20 m apart, turning on each beep. The beeps speed up every minute. The result is the last stage (level) you complete before you can no longer reach the line in time. In the 1988 protocol, stage 1 runs at 8.5 km/h and each stage adds 0.5 km/h, so the speed of the stage you reach is S = 8 + 0.5 × level km/h.

That stage speed feeds the Léger VO2 max equation (Léger et al. 1988):

The stage speed is also your maximal aerobic speed (MAS) — the pace at the top of the test — which is a useful training number on its own, with none of the regression's error. The VO2 max is a conversion layered on top of it.

The equation was fit on 188 children and adolescents aged 8–19, where it correlated r = 0.71 with measured VO2 max — so it accounts for about half (r² ≈ 0.50) of the person-to-person variation. For adults, Léger validated it on 77 men and women aged 18–50 by holding age constant at 18 (r = 0.90). That is deliberate: the age term tracks childhood maturation, not adult aging, so this page substitutes A = 18 on the Adult setting and your entered age on the Youth setting.

Worked example

A 14-year-old completes level 9 (Scenario BEEP1). The stage speed is 8 + 0.5 × 9 = 12.5 km/h (7.77 mph) — that is the maximal aerobic speed. Youth setting, so age 14 goes in:

• VO2max = 31.025 + 3.238×12.5 − 3.248×14 + 0.1536×14×12.5
• = 31.025 + 40.475 − 45.472 + 26.88 = 52.9 mL/kg/min

Now a 30-year-old who reaches the same level 9 (12.5 km/h / 7.77 mph, Scenario BEEP2). On the Adult setting the equation uses age 18:

• Age held at 18: 31.025 + 40.475 − 3.248×18 + 0.1536×18×12.5 = 47.6 mL/kg/min
• If the real age 30 were used instead: 31.025 + 40.475 − 3.248×30 + 0.1536×30×12.5 = 31.7 mL/kg/min

Same run, two answers 15.9 mL/kg/min apart — all from one age setting. The 47.6 figure is the one Léger's adult validation supports; the 31.7 is what you get when a calculator plugs a real adult age into a youth equation.

When this calculator is wrong

The beep test's VO2 max comes from an equation fit on 8–19-year-olds, and its age term tracks childhood maturation, not adult aerobic decline — which is why Léger's own adult validation froze age at 18. Across the test's speed range (8.5–18.5 km/h) adding years always lowers the predicted VO2 max, because the age coefficient (−3.248) outweighs the speed×age term until about 21 km/h — past the top stage. So feeding a real adult age extrapolates a youth-development effect: the 30-year-old above drops from 47.6 to 31.7 mL/kg/min on that one setting. Léger validated adults (n = 77, ages 18–50) by holding age at 18 for exactly this reason.

• The level you reach is the real result; the VO2 max is a soft layer on top. An r of 0.71 in the youth sample means the equation explains only about half the between-person variance — the rest is running economy, motivation, pacing, and test-day conditions. Treat the VO2 max as a rough placement, and track the level (and the maximal aerobic speed it sets) test-to-test, which needs no equation.
• It rewards pacing and turning technique, not just aerobic power. The shuttle format punishes poor deceleration and re-acceleration at each 20-m turn. A heavier or less agile runner spends more energy per turn, so two people with the same lab VO2 max can finish at different levels. The test travels well for running populations and worse for others.
• Trained adults are often underestimated. Because the equation was built on a mixed youth cohort and capped at age 18 for adults, it tends to read low for well-trained endurance athletes — a lab test or a Cooper/Rockport estimate is a better cross-check at the high end.
• Protocol matters. The 1988 version used here starts at 8.5 km/h with 1-minute stages. Some apps and audio tracks use the 1982 start (8.0 km/h, 2-minute stages) or a different stage layout; a level from one protocol is not the same speed as the same level number from another.

What to do with the result

Use the level as your primary tracking number. Re-run the same protocol every 6–8 weeks under similar conditions (surface, temperature, warm-up) and watch the level move — that change is a cleaner signal of aerobic progress than the VO2 max digits, because it carries none of the regression error and all of the same-person consistency.

Use the maximal aerobic speed (the stage speed, in km/h or mph) to set interval pacing: short, hard intervals are often run at or just above MAS, with easy running well below it. And put the VO2 max estimate in context rather than treating it as exact — compare it against the age- and sex-based reference medians on the VO2 max calculator, which carries the Cooper Institute values, instead of chasing a single number.

Common questions

How is VO2 max calculated from the beep test?

From the speed of the last stage you complete and your age, using the Léger 1988 equation: VO2max = 31.025 + 3.238×S − 3.248×A + 0.1536×A×S, where S is the stage speed in km/h (S = 8 + 0.5 × level) and A is age. For example, level 9 is 12.5 km/h; a 14-year-old there scores about 52.9 mL/kg/min.

Why does the calculator use age 18 for adults?

Because that is how Léger validated the test in adults. The equation was fit on children and teenagers (8–19), and its age term reflects childhood maturation, not adult aging. For the adult sample (18–50, r = 0.90) the authors held age constant at 18. Plugging in your real adult age extrapolates a youth effect and pushes the estimate implausibly low — a 30-year-old at level 9 reads 31.7 mL/kg/min with age 30 but 47.6 with age held at 18.

What is a good beep test score?

There is no single primary normative table — the untrained-to-elite level charts you see circulating are aggregator data, not peer-reviewed norms, so we don't print them. The honest reads are: compare the level to your own past tests, and compare the VO2 max estimate against the age- and sex-based reference medians on our VO2 max page. Reaching a higher level than last time is the result that matters.

What is maximal aerobic speed and how do I use it?

Maximal aerobic speed (MAS) is the running speed at the top of the test — here, the final stage speed, S = 8 + 0.5 × level km/h. It is a pacing anchor: many interval sessions are built around running at or near MAS for the hard reps and well under it for recovery. Unlike the VO2 max estimate, MAS comes straight off the test with no regression, so it carries none of the equation's error.

Is the beep test the same as the PACER?

The PACER (Progressive Aerobic Cardiovascular Endurance Run) is the 20-metre multistage shuttle run run in US schools — same test, same 20 m course and progressive beeps. Level and lap numbering can differ slightly by audio track, so match the protocol you ran (1988: 8.5 km/h start, 1-minute stages) to the one the calculator assumes.

How accurate is the beep test for VO2 max?

As a field test, moderately. The Léger youth equation correlates r = 0.71 with measured VO2 max (about half the variance explained), and the adult convention reaches r = 0.90 but still leaves meaningful individual spread. It is best for tracking the same person over time and for group screening, not for a precise one-off number. For well-trained endurance athletes it tends to read low.