Ironman Calculator

Comprehensive triathlon race planning calculator for sprint, Olympic, 70.3, and Ironman distances. Six tabbed sections: (1) Swim - pace per 100m with wetsuit benefit and sighting/drafting adjustments; (2) Bike - intensity (% of FTP), aerodynamic position (CdA 0.22-0.32), gradient, and course hilliness multiplier; (3) Run - fresh open pace with triathlon slowdown adjustment; (4) Transitions - T1 (swim to bike) and T2 (bike to run) times; (5) Nutrition - carb intake (g/h for bike and run), fluid intake (mL/h), and sodium (mg/h) with gel and bottle calculations; (6) Summary - total time prediction, visual time split bar, elapsed times, percentage breakdown, and standard race cutoffs with pass/fail status. Physics model includes rolling resistance, aerodynamic drag, and drivetrain loss. Real-time calculations update all tabs. Light and dark mode support.