Tools you might need next
Calculate swimming pace per 100m or 100yd from split times and distance. Convert between pace formats for pool and open water training plans.
Calculate calories burned swimming by stroke, intensity, duration, and body weight. Estimate energy expenditure for pool and open water workouts.
Calculate critical swim speed (CSS) threshold pace from 400m and 200m time trial results. Set aerobic training zones for swimmers and triathletes.
Calculate great-circle distance between GPS coordinates in meters. Sum segments between consecutive waypoints for total course length.
d = 2R × arcsin(√(sin²(Δlat/2) + cos(lat1)cos(lat2)sin²(Δlon/2)))Sighting errors, current, and non-optimal routing add 5–15% to straight-line distance. Use higher factors for choppy conditions or poor visibility.
Actual distance ≈ Straight-line × 1.05–1.15Multiply adjusted distance by your open water pace (typically 5–10% slower than pool CSS) for realistic finish time estimates.
Finish time = Adjusted distance × Pace per meterUpdated: July 2026
GPS track of an Olympic-distance 1500m swim shows 1620m actual due to navigation — adjust race pacing expectations accordingly.
Place three buoys forming a triangle; calculate segment distances to verify total course meets sanctioning requirements within 5% tolerance.
Map a 2000m loop between two shore landmarks using waypoint distances to structure open water training without a measured course.
Open water courses rarely follow straight lines due to navigation, currents, and sighting. Enter GPS waypoints from buoys or your swim track to calculate straight-line and adjusted distance for race planning and training volume tracking.