How this calculator works
The plan starts from a base weekly volume for the race distance and adjusts it for your endurance background and your goal. A longer race needs more volume, a stronger background tolerates more, and an ambitious goal adds a little more again. The weeks are then divided into base, build, peak and taper phases. Base weeks are slightly below the average. Build weeks reach the average, peak weeks go above it, and the taper drops the volume to arrive fresh. The swim, bike and run shares reflect the race: swimming is the smallest time commitment, cycling is the largest, and running is large enough to build durability without overloading the legs.
Formula
Average weekly hours = base hours for the race x background factor x goal factor. Base hours are 5 for sprint, 7 for Olympic, 10 for half Ironman and 13 for Ironman. Background factors are 0.8, 1.0 and 1.25. Goal factors are 0.9, 1.0 and 1.15. Swim, bike and run shares are 20, 45 and 35 percent. Phase multipliers are 0.85 base, 1.0 build, 1.1 peak and 0.65 taper.
Worked example
An Olympic distance with a modest background and a goal of finishing strong uses 7 x 1.0 x 1.0 = 7 hours a week over 12 weeks. That is 5 weeks of base at 5.95 hours, 4 weeks of build at 7 hours, 2 weeks of peak at 7.7 hours and a one week taper at 4.55 hours. Each normal week has 1.4 hours of swimming, 3.15 hours of cycling and 2.45 hours of running.
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Frequently asked questions
Is this a complete training plan?
No. It sets weekly volume and the balance between sports, but not individual sessions, intensities or rest weeks. Use it as a sanity check on your own plan or as a starting point to discuss with a coach.
Why does cycling get the largest share?
The bike leg is the longest part of most triathlons and the safest place to add aerobic volume, because it carries less impact than running. Running volume is capped by injury risk rather than by race distance.
How much can a beginner increase volume?
A common guide is no more than about ten percent per week, with a lighter week every third or fourth week. The base phase here already starts below the average for that reason.
Should I train by hours or by distance?
Hours are more portable across sports and courses, especially for swimming and cycling where weather and terrain change distance quickly. Use distance for key sessions such as a long ride or a race-pace run, and hours for the overall weekly load.