Triathlon Nutrition Calculator

Fueling a long triathlon means hitting carb, fluid and sodium targets each hour.

How the Math Works

The Triathlon Nutrition Calculator uses a straightforward mathematical formula: total = rate × hours. This equation multiplies your target intake rate (measured in grams of carbohydrate, ounces of fluid, or milligrams of sodium per hour) by your estimated race duration in hours. For example, if you need 30g of carbs per hour and expect to race for 3.5 hours, the calculation becomes 30 × 3.5 = 105g total carbohydrates needed. The same principle applies independently to fluid and sodium calculations, allowing you to determine precise total amounts for each nutrient category.

Practical Applications

To use this calculator practically, first determine your personal hourly needs through training. For a 2-hour swim/bike/run segment, you might need 20g carbs/hour for the bike portion and 30g carbs/hour for the run. Input your race duration and desired hourly rates to calculate pre-race meal planning and on-course fueling strategy. If your calculated total fluid need is 64 ounces over 8 hours, you know to carry 16-20oz bottles and plan hydration station stops accordingly. This prevents both under-fueling that causes bonking and over-fueling that leads to nausea.

Day-to-Day Use

This calculator transforms triathlon training from guesswork into precise fuel management, helping you understand your body's actual energy requirements. Beyond race day, the hourly rate concept applies to daily nutrition planning—whether you're meal prepping for endurance training weeks or determining sports drink needs for long runs. The core formula itself teaches valuable life math: budgeting any rate against time duration, whether calculating water intake during hikes, medication schedules, or project resource allocation. You'll develop lasting skills in quantifying and planning for sustained physical demands.

Worked example

3 hours at 60 g/h → 180 g carbs, 1800 ml fluid, 1500 mg sodium.

FAQ