Fitness Calculators
Free calculators for calories burned, running pace, and heart rate training zones. Train smarter with data-driven fitness tools.
Fitness Calculators - Turn Training Effort into Measurable Results
The difference between exercising and training is measurement. When you know your calories burned per session, your target heart rate zone for a specific adaptation, or the exact pace needed to hit a race time goal, every workout becomes purposeful.
Three Fitness Calculators
Calories Burned Calculator - Estimates energy expenditure for specific physical activities using MET (Metabolic Equivalent of Task) values from the Compendium of Physical Activities. Enter body weight, activity type, and duration. Activities include walking, running, cycling, swimming, HIIT, yoga, and weightlifting. Shows total kcal and equivalent food items for intuitive reference.
Running Pace Calculator - Three modes: find pace (min/km or min/mile) for a target distance and finish time; find finish time from pace and distance; find distance from pace and time. Covers 5K, 10K, half marathon (21.1 km), and full marathon (42.195 km). Essential for race planning and parkrun personal-best targeting.
Heart Rate Zone Calculator - Five zones based on Maximum Heart Rate using both the standard formula (220 − age) and the Tanaka formula (208 − 0.7 × age, more accurate for fit adults). Optionally uses the Karvonen method (Heart Rate Reserve) for personalised zones based on resting HR. Zone 1: recovery, Zone 2: aerobic base, Zone 3: tempo, Zone 4: lactate threshold, Zone 5: VO2 max.
Training With Heart Rate Zones
Most recreational runners spend too much time in Zone 3–4 (“the grey zone”) - uncomfortable but not hard enough for real threshold adaptations. Effective endurance training follows an 80/20 split: 80% of volume in Zone 1–2 (conversational pace) and 20% in Zone 4–5 (interval work). The Heart Rate Zone Calculator gives you exact bpm ranges for each zone, and the Running Pace Calculator translates those zones into target min/km paces.
For weight management, combine the Calories Burned Calculator with the Calorie Deficit Calculator to see your daily energy balance.
Frequently Asked Questions
Which heart rate zone is best for fat burning?
Zone 2 (60–70% MHR) maximises the proportion of fat as fuel. Higher zones burn more total calories per minute, so absolute fat burned can exceed Zone 2 despite the lower percentage. Use the Heart Rate Zone Calculator to find your Zone 2 bpm range.
How do I find my maximum heart rate?
The most accurate method is a maximal exercise test (run hard up a hill until exhaustion). The 220−age formula has ±12 bpm standard deviation. The Heart Rate Zone Calculator supports both formulas plus the Karvonen reserve method.
What pace should a beginner run to complete a 5K?
Most beginners complete a first 5K in 35–45 minutes (7:00–9:00 min/km). For a 30-minute 5K, you need 6:00 min/km. Use the Running Pace Calculator to find the exact pace for any finish-time target.
Does the calories burned calculator account for fitness level?
No - MET calculations use population averages. A highly fit person burns fewer calories doing the same activity due to greater mechanical efficiency. The Calories Burned Calculator provides a useful baseline; track actual weight changes over time to calibrate your real calorie balance.