Fitness Calculators
Whether you're tracking calories burned, calculating your one rep max, or finding your heart rate training zones — our free fitness calculators give you the numbers to train smarter.
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Cardio & Running
Pace, calories burned, heart rate, and VO2 Max
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Fitness Glossary — Key Terms Explained
- MET (Metabolic Equivalent)
- A measure of exercise intensity. Sitting = 1 MET. Walking briskly = 3.5 MET. Running at 10 km/h = 9.8 MET. Used in the formula: Calories = MET × weight (kg) × time (hours).
- VO2 Max
- The maximum rate at which your body can consume oxygen during intense exercise, measured in ml/kg/min. The gold standard measure of aerobic fitness. Elite runners score 60–85; recreational runners 35–50.
- 1RM (One Rep Max)
- The maximum weight you can lift for a single repetition. Used to set training loads as percentages. Estimated using formulas from submaximal sets — actual testing not always required.
- EPOC
- Excess Post-Exercise Oxygen Consumption — the elevated calorie burn after intense exercise while the body recovers. Can add 6–15% to exercise calorie burn for HIIT or heavy strength training sessions.
- Heart Rate Reserve (HRR)
- The difference between maximum heart rate and resting heart rate (HRR = Max HR − Resting HR). Used in the Karvonen method for more accurate heart rate zone calculation.
Frequently Asked Questions
How many calories does running burn?
Running burns approximately 80–100 calories per mile for a 70 kg (155 lb) person. More precisely, use the MET formula: 9.8 × weight (kg) × time (hours). Pace, bodyweight, terrain, and running efficiency all affect exact calorie burn.
What is Zone 2 training?
Zone 2 is 60–70% of your maximum heart rate — a conversational pace where you can speak in full sentences. It primarily burns fat as fuel and builds aerobic base (mitochondrial density). Most endurance athletes spend 75–80% of training in Zone 2.
How do I estimate my 1RM without maxing out?
Use the Epley formula: 1RM = Weight × (1 + Reps ÷ 30). For example, bench pressing 80 kg for 6 reps gives an estimated 1RM of 80 × (1 + 0.2) = 96 kg. Best accuracy is with 3–8 rep sets — estimates become less reliable above 10 reps.
How accurate are calorie burn estimates from fitness trackers?
Consumer fitness trackers have been shown to vary by ±15–30% from lab-measured calorie expenditure. The MET formula is a validated research standard but still shows ±15% individual variation. Both are estimates — use them for planning, not precise accounting.