DIY Sports Drink Calculator
Enter your body weight, workout duration, exercise intensity and temperature, and this calculator builds a precise homemade sports drink recipe for you. You get the exact grams of sugar or honey, teaspoons of salt, optional potassium, millilitres of lemon juice, and how much water to mix. It also shows your estimated sweat loss, sodium and carbohydrate targets, total calories, and what the recipe costs compared to a commercial sports drink.
Why make your own sports drink?
Commercial sports drinks such as Gatorade and Powerade are convenient, but they are expensive (roughly $1.00 to $1.50 per 600 mL bottle), often overly sweet, and contain artificial colours and flavours that some athletes prefer to avoid. A homemade version made from water, sugar or honey, a pinch of salt, and a splash of lemon juice replicates the function of a commercial drink - replacing fluid, carbohydrates, and sodium lost in sweat - for a fraction of the cost. The key insight is that a sports drink is essentially just a precise solution: the right concentration of carbs for energy and the right amount of sodium to help you absorb fluid and retain it. Everything else is marketing.
How the recipe is calculated
This calculator starts from your body weight, exercise duration, intensity, and environmental conditions to estimate your sweat rate (in litres per hour). Sweat rate is scaled from research averages: a 70 kg athlete exercising at moderate intensity in average conditions sweats at roughly 0.9 L/h, rising to 1.9 L/h at race pace in the heat. Your fluid target is set at 80% of expected losses, which aligns with consensus guidance that replacing 100% in real time can lead to over-hydration (hyponatremia) in susceptible individuals. Carbohydrate need is derived from the drink concentration you choose: a 6% isotonic solution contains 6 g of sugar per 100 mL, so 750 mL of drink delivers 45 g of carbs. Sodium target is 500 mg per litre - the midpoint of the widely recommended 400 to 700 mg/L range for sweat replacement. Everything is then scaled down to one bottle so you can make up exactly what you need.
Sodium, potassium, and electrolytes explained
Sodium is the most important electrolyte to replace during exercise. It is lost in the greatest quantity through sweat (typically 400 to 1,000 mg/L depending on the individual), and replacing it helps drive thirst, supports fluid absorption in the gut, and prevents dangerous low-sodium states in long events. Potassium is also lost in sweat but at much lower concentrations (around 150 to 200 mg/L). For sessions under two hours, the sodium in food and drink is usually sufficient, but in long hot races some athletes add a small amount of potassium chloride (sold as No Salt or Nu-Salt) to their bottles. Magnesium is lost in smaller amounts still and is rarely needed in the drink itself for most athletes. The optional lemon juice in this recipe adds a trace of potassium and natural flavour without any cost or complexity.
Hypotonic, isotonic, and hypertonic: which should you choose?
The terms refer to how concentrated the drink is relative to blood plasma. An isotonic drink (around 6 to 8% carbs) matches body fluid concentration and is the standard choice for most endurance events because it delivers a useful amount of carbs while still emptying from the stomach at a reasonable rate. A hypotonic drink (below 4%) is more dilute, absorbs faster, and is best when your primary need is fluid replacement rather than energy - useful in short hot sessions. A hypertonic drink (above 8%) delivers more carbs per mouthful but empties from the stomach more slowly and can cause gastric distress in some athletes; it is most useful as a recovery drink after a race, or as a concentrated top-up between stages in a multi-day event rather than as a primary in-event drink.
Carbohydrate concentration guide
| Type | Carb concentration | Best for | Gastric emptying |
|---|---|---|---|
| Hypotonic | 2-4% | Hot weather, short sessions, rapid hydration | Fastest |
| Isotonic | 6-8% | Most endurance events (1-3 h) | Moderate |
| Hypertonic | 8-12% | Recovery drinks, very long events (3+ h top-up) | Slower |
Choose based on your primary need: rapid fluid absorption vs. carb delivery.
Frequently asked questions
How much fluid should I drink per hour of exercise?
A useful starting point is 400 to 800 mL (13 to 27 fl oz) per hour, scaled to your body weight, intensity and conditions. Smaller, lighter athletes and those exercising in cool weather will sit toward the lower end; larger athletes and those training in the heat will sit higher. Drinking to thirst is a reliable guide for most recreational athletes; the main risk of drinking to a rigid schedule is over-hydration if you consistently drink more than you sweat.
How much sodium should be in a homemade sports drink?
Most sports nutrition guidelines recommend 400 to 700 mg of sodium per litre of fluid consumed during exercise, with 500 mg/L being a practical midpoint. That translates to roughly one quarter teaspoon of table salt per 750 mL bottle. Athletes who are heavy sweaters or who sweat very salty (you will see white crust on your skin or kit) may need up to 1,000 mg/L, especially in heat.
Can I use honey instead of sugar?
Yes. Honey is roughly 82% carbohydrate by mass compared to 100% for white sugar, so you need slightly more honey to hit the same carb concentration (about 22% more by weight). Honey also contains trace amounts of potassium, antioxidants, and has a lower glycaemic index than pure sucrose, though the difference in practice is small. The main downside is cost and the fact that honey is stickier and harder to dissolve in cold water - mixing in warm water first helps.
Do I need to add potassium to my sports drink?
For most sessions under two hours, no. Sweat contains far more sodium than potassium, and the potassium in normal food and drink is usually adequate. For longer events, particularly in the heat, adding a small amount of potassium chloride (sold as No Salt) can help: roughly a quarter teaspoon per litre. If you are on medication that affects potassium (such as ACE inhibitors or potassium-sparing diuretics), check with your doctor before adding extra potassium.
When do I need a sports drink vs. plain water?
Plain water is sufficient for most sessions under 60 minutes at moderate intensity in comfortable temperatures. Once you cross about 60 to 90 minutes, or any duration in hot and humid conditions, adding carbohydrates and sodium to your fluid intake improves performance and safety. The longer and hotter the event, the more important the electrolytes become.
How much cheaper is a DIY sports drink than Gatorade?
A homemade drink using white sugar, table salt, and water costs roughly $0.05 to $0.15 per 750 mL bottle, compared to $1.00 to $1.50 for a commercial equivalent. Over a season of training that adds up quickly. Adding honey and lemon raises the DIY cost slightly but it is still typically 70 to 90% cheaper than commercial options.
Is a 6% carbohydrate solution the right concentration for running?
Six percent (6 g of carbs per 100 mL, or 45 g per 750 mL bottle) is the most studied concentration for endurance exercise and is the standard used by most commercial sports drinks. The gut can absorb roughly 60 to 90 g of carbohydrate per hour from a drink, so a 6% solution drunk at a rate of 750 to 1,000 mL per hour sits comfortably within that window. Higher concentrations can slow gastric emptying and increase the risk of stomach upset during high-intensity efforts.