Swimming Distance & Lap Counter
Calculate swimming distance from laps, convert between pool and open water distances, and plan training sessions based on pace.
Swimming Distance Guide
Pool Lengths and Distance
25m pool: 2 lengths = 50m. 4 lengths = 100m. 20 lengths = 500m. 40 lengths = 1000m (1km). 60 lengths = 1500m (approximately a mile — 1 mile = 1609m = 64.4 lengths). 50m pool: 2 lengths = 100m. 20 lengths = 1000m. 30 lengths = 1500m. 76 lengths = 3800m (Ironman). A lap vs a length: in swimming, confusion exists. In most UK leisure pools, 'one lap' = one length (one way). In American usage, 'one lap' often means two lengths (there and back). This calculator uses lengths (one way), but always confi
Calorie Burn in Swimming
Swimming burns significantly fewer calories than running at the same time because: water support reduces effort against gravity. Less post-exercise oxygen consumption. Cooling effect of water reduces thermogenic calorie burn. Approximate calorie burn (75kg swimmer): easy freestyle: 400-500 kcal/hour. Moderate freestyle: 500-600 kcal/hour. Fast/competitive: 600-700 kcal/hour. Breaststroke: 500-650 kcal/hour (higher energy per metre). Butterfly: 600-800 kcal/hour (most demanding). For weight loss
Open Water vs Pool Swimming
Converting pool pace to open water time: most swimmers are 3-8% slower in open water. Factors slowing open water times: sighting (lifting head to navigate — 3-5% energy cost). No walls to push off. Chop, current, and navigation error. Wetsuit: adds buoyancy — can improve speed 3-5% vs pool. Net effect: for the same fitness level, open water times are usually slightly slower than pool times, but wetsuit-legal races may be comparable or faster. Distances: triathlon swim courses are measured along
Building a Swim Training Plan
Total weekly yardage approach: beginners: 1000-2000m/week in 2-3 sessions. Intermediate: 3000-5000m/week. Advanced: 5000-10,000m/week. Session structure: warm-up (400-600m easy). Main set (intervals or continuous). Cool-down (200-400m easy). Interval examples: 10×100m with 20 seconds rest (builds pace and efficiency). 5×200m descending (getting faster each set). 1×1500m continuous (builds aerobic base). The drill: kick on side, catch-up, fingertip drag, single-arm — target specific technique ele
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