Heart Rate Calculator

Your heart has a redline, just like a car engine. This calculator finds yours and maps out the five training zones built on top of it. Start with maximum heart rate — roughly 220 minus your age — then subtract your resting heart rate to get your heart rate reserve. That reserve is the working range your training zones slice up: Zone 1 at 50 to 60 percent for warm-ups, Zone 2 at 60 to 70 percent for fat burning, Zone 3 at 70 to 80 percent for aerobic fitness, Zone 4 at 80 to 90 percent for anaerobic threshold work, and Zone 5 above 90 percent for all-out efforts.

Consider a 30-year-old cyclist in Austin with a resting pulse of 65. His max lands near 190, his reserve is 125 beats, and his Zone 2 — the sweet spot endurance athletes obsess over — runs about 140 to 153 beats per minute. That is the pace where he can still hold a conversation, burn mostly fat, and ride for hours. The same math gives a sprinter her Zone 4 and 5 targets for interval days.

The 220-minus-age formula is a population average and can miss individuals by 10 to 20 beats. Athletes with known max heart rates from testing should use those numbers instead. If you have a heart condition, get medical clearance before training in the upper zones.