Cardio calculator
Bruce protocol calculator
Estimate VO₂ max from how long you lasted on the Bruce treadmill test — enter your total time, age, and sex. Free, instant, no sign-up.
Treadmill time improves with structured threshold and interval work — the coach schedules it.
What is the Bruce protocol?
The Bruce protocol is the most widely used treadmill stress test. It starts at 1.7 mph on a 10% incline and steps up both speed and grade every three minutes until you stop. Because the workload climbs in a fixed, documented way, the total time you hold on is a good proxy for maximal aerobic capacity — which is why cardiologists and coaches have used the same seven stages since 1963.
How this calculator works
For men we use the Foster et al. (1984) regression: VO₂ max = 14.76 − 1.379 × T + 0.451 × T² − 0.012 × T³. For women we use Pollock et al. (1982): VO₂ max = 4.38 × T − 3.90. In both, T is total time in minutes as a decimal, so 12 minutes 30 seconds is 12.5. METs are the same number divided by 3.5, and the age average comes from Bruce et al. (1973).
Reading the result honestly
The men's and women's equations come from different studies with different samples, so the two numbers are not directly comparable with each other — compare yourself with your own previous tests instead. Holding the handrails inflates your time and therefore your estimate, and a maximal treadmill test is not something to run alone or without medical clearance if you have any cardiac risk.
Bruce protocol stage table
Every stage lasts three minutes. Twenty-one minutes finishes the whole standard protocol.
| Stage | Ends at | Speed (mph) | Grade (%) |
|---|---|---|---|
| 1 | 3:00 | 1.7 | 10 |
| 2 | 6:00 | 2.5 | 12 |
| 3 | 9:00 | 3.4 | 14 |
| 4 | 12:00 | 4.2 | 16 |
| 5 | 15:00 | 5.0 | 18 |
| 6 | 18:00 | 5.5 | 20 |
| 7 | 21:00 | 6.0 | 22 |