Skip to main content
Calcimator

Race Day Nutrition Calculator

Plan your race fueling strategy — carbs per hour, fluid, gels, and sodium based on distance, pace, and sweat rate.

Inputs

miles
min/mile
lbs
ml/hr

Results

Carbs Per Hour

45 g/hr

Fluid Per Hour

20 oz/hr

Total Carbs Needed88 g
Gels Needed2
Sodium Needed786 mg
Body Weight Kg70.29
How to Use This Calculator
  1. Enter the race distance and your estimated finish time.
  2. Set your body weight and sweat rate if known.
  3. Input your planned pre-race meal timing and content.
  4. Review the Carbohydrate Per Hour, Fluid Per Hour, and Electrolyte Targets during the race.
  5. Use the Aid Station Plan output to map out exactly when and what to consume along the course.

What each input means

Race Distance
Total race distance (e.g., 13.1 for half marathon, 26.2 for marathon)
Pace
Expected pace in minutes per mile
Body Weight
Your body weight in pounds
Sweat Rate
Your sweat rate in milliliters per hour (weigh before/after a 1-hr run to estimate)

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Race Distance = 13.1, Pace = 9, Body Weight = 155, Sweat Rate = 800 = 4 input(s) provided
  2. Calculate Carbs Per Hour
    45 = 45
  3. Calculate Fluid Per Hour
    20 = 20
  4. Calculate Total Carbs Needed
    Total Carbs Needed
    88 = 88
  5. Calculate Gels Needed
    Gels Needed
    2 = 2

Engine last updated . Checked against 2 independently-derived tests — how we verify calculators.

Related Calculators

The questions that sit next to this one — chosen by subject, including calculators filed under a different category.

Sports Nutrition

Electrolyte Replacement Calculator

Calculate sodium, potassium, and magnesium needs during exercise based on sweat rate, duration, and climate.

Sports Nutrition

Rehydration Calculator

Calculate sweat loss, sweat rate, and rehydration needs based on pre/post exercise weight and fluid intake.

Triathlon

Ironman Nutrition Plan Calculator

Calculate hourly calorie, carb, sodium, and fluid intake targets for Ironman and long-course triathlon racing.

Running & Race Training

Ultra Marathon Nutrition Calculator

Plan calories, electrolytes, and fluid intake per hour for ultra marathon distances. Get personalized nutrition targets based on weight, pace, and conditions.

Adventure Racing

Ultra Endurance Nutrition Calculator

Calorie and electrolyte plan for events over 12 hours.

More in Health & Fitness.