About TriSplitCalc
TriSplitCalc is a free race-planning toolkit for triathletes who want clearer swim, bike, run, transition, and fueling estimates before race day. The calculators are built to make pacing tradeoffs visible, not to promise an exact result.
Published by M Imtinan Farooq
Age-group triathlete and data engineer. I built TriSplitCalc to plan my own races, and publish the pacing, split, and nutrition models behind it in full so other athletes can check the assumptions rather than trust a black box.
TriSplitCalc started as a set of spreadsheets I built for my own racing. I wanted to know whether a goal time was actually achievable before I committed a season to it, and specifically whether the bike split I had in mind would leave me able to run. The calculators on this site are those spreadsheets, cleaned up and made public.
What I am is an age-group athlete who works with data for a living. What I am not is a coach, a physiologist, or a dietitian, and I think it matters that the difference is stated plainly rather than blurred. This site gives you planning arithmetic and shows its working. It does not give medical, nutritional, or individual coaching advice, and where a question genuinely needs one of those, you should ask a qualified professional rather than a calculator.
Because I cannot offer credentials as the reason to trust the numbers, I offer transparency instead. Every formula, modifier, and assumption is published on the methodology page, the sources are listed below, and each calculator states its own limitations on the page rather than in the small print. Where the honest answer is “this is a broad planning estimate, not a prediction”, the tool says so.
If you find an error, or a case where a model gives a result that does not match your race experience, I would genuinely like to hear about it — corrections from athletes are how these models have improved. You can reach me through the contact page.
Calculation Methodology
Swim time is distance divided by pace, expressed per 100 metres or 100 yards. The calculator converts yards and metres before producing the split.
Bike time is distance divided by average speed. The output assumes your entered speed already reflects terrain, wind, position, traffic, and course conditions.
Run time is distance multiplied by pace. For triathlon planning, run-off-bike pace is usually more useful than standalone race pace.
Total finish time is calculated as swim split plus T1 plus bike split plus T2 plus run split. Nutrition estimates use hourly targets multiplied by expected bike and run duration, then convert those targets into bottles, gels, sodium, and total intake ranges.
Assumptions and Safety Limits
TriSplitCalc does not know your medical history, heat tolerance, swim confidence, injury status, equipment, course profile, or weather. Treat every output as a planning range. Use race-specific rules, athlete guides, coach feedback, and your own training data before making final decisions.
Wetsuit, temperature, drafting, and cutoff rules can vary by organizer and event. Always confirm the athlete guide for your race before relying on a general benchmark.