Sports Drink Calculator Formula

Understand the math behind the sports drink calculator. Each variable explained with a worked example.

Use the Sports Drink Calculator

Formulas Used

Sugar/Carb Powder

sugar_g = round(water_ml * carb_pct / 100 * intensity)

Salt (sodium)

salt_g = round(water_ml * 0.001 * intensity * 10) / 10

Total Fluid Needed

total_fluid_ml = round(water_ml * duration_hr)

Bottles (750 mL)

bottles = ceil(water_ml * duration_hr / 750)

Variables

VariableDescriptionDefault
water_mlWater Volume(mL)750
intensityActivity Intensity1
duration_hrActivity Duration(hr)1.5
carb_pctDerived value= 4 + intensity * 2calculated

How It Works

How to Mix a Sports Drink

Carbohydrate Concentration

Sports drinks should be 4-8% carbohydrate for optimal absorption:

  • Light activity: 4-5% (lower end)
  • Moderate activity: 5-6%
  • Intense activity: 6-8%

    • Concentrations above 8% slow gastric emptying and can cause stomach issues.

    Sodium

    Add 0.5-1.0 g of sodium per liter of water. This replaces sweat losses and improves fluid absorption. Heavy sweaters may need more.

    Mixing

    Dissolve sugar and salt in warm water, then add cold water and ice. Taste should be mildly sweet, not overpowering.

    Worked Example

    Mix a sports drink for a 1.5-hour moderate run using 750 mL of water.

    water_ml = 750intensity = 1duration_hr = 1.5
    1. 01Carb percentage = 4 + 1 x 2 = 6%.
    2. 02Sugar = 750 x 6/100 x 1 = 45 g (about 3 tablespoons).
    3. 03Salt = 750 x 0.001 x 1 = 0.8 g (about 1/8 tsp).
    4. 04Total fluid needed = 750 x 1.5 = 1125 mL.
    5. 05Bottles = ceil(1125 / 750) = 2 bottles.

    Frequently Asked Questions

    Can I use regular table sugar?

    Yes. A mix of sucrose (table sugar) and glucose works well. For even better absorption, use a 2:1 ratio of glucose to fructose, which allows the gut to absorb more carbohydrate per hour via different transporters.

    Do I need a sports drink for short workouts?

    For activities under 60 minutes at moderate intensity, plain water is sufficient. Sports drinks become beneficial for sessions over 60-90 minutes, in high heat, or during intense effort.

    How much should I drink per hour?

    General guideline: 400-800 mL per hour, depending on sweat rate, temperature, and body size. Weigh yourself before and after exercise. Each pound lost equals about 480 mL of fluid deficit.

    Ready to run the numbers?

    Open Sports Drink Calculator