Race nutrition calculator

For races over 2 hours, aim for 60 to 90 g of carbohydrate per hour, and up to 120 g if your gut is trained. Drink to replace most, not all, of your sweat, and match sodium to how salty you sweat. Enter your race below to get carbs, fluid and sodium per hour, totals and a 20-minute rhythm.

Calculator

Expected race time

Hours:minutes

Body weight

Sweat rate

Conditions

How salty do you sweat?

My gut is trained for high carb intake

On if you regularly eat 80 g/h or more on long rides without stomach problems.

Carbs

75g/h

range 60–90 g/h

Fluid

550mL/h

Sodium

500mg/h

For 4:30: 338 g carbs · 2.5 L fluid · 2,250 mg sodium

Every 20 minutes: about 25 g carbs and 180 mL to drink.

What that could look like

Per hour: 1.1 bottles (500 mL) of drink mix with 40 g carbs each, plus 1 gel (25 g).

Carb intake options for this distance

Intake	Total for the race	Gels equivalent
75 g/h	338 g	about 14 gels
90 g/h (recommended for you)	405 g	about 16 gels

Carbs: 30–60 g/h (1–2 h), 60–90 g/h (2–4 h), up to 90–120 g/h over 4 h when gut-trained. Fluid: about 75 % of sweat losses, 400–1,000 mL/h. Sodium: fluid × sweat sodium.

How the race nutrition calculator works

Race nutrition comes down to three numbers per hour: carbohydrate, fluid and sodium. The right amounts depend on how long you race, how much and how salty you sweat, and how much carbohydrate your gut has learned to handle. The calculator combines those into a plan you can put in your bottles and pockets. It is part of the free LeCoach cycling calculators, and it uses the same guidelines as our guide to race fueling for cyclists.

Carbohydrate per hour, by race duration:

Race duration	Carbs per hour	Notes
Under 1 hour	0–30 g	Optional. A carb drink or mouth rinse can help late in the race.
1 to 2 hours	30–60 g	One source, such as glucose or maltodextrin, is fine
2 to 4 hours	60–90 g	Use a glucose and fructose mix (about 1:0.8)
Over 4 hours	60–90 g, or 90–120 g if gut-trained	High intakes only if you have practised them

The calculator takes the middle of the range, or the top if you say your gut is trained.

Fluid. You do not need to replace every drop you sweat. The calculator aims to replace about 75 % of your sweat losses, between 400 and 1,000 mL per hour (most stomachs cannot empty much more than that), and never more than you sweat. It also shows how much body weight you would lose at that intake; keeping it under about 2 % protects performance.

Sodium. You lose sodium with sweat, from roughly 500 mg per litre for light sweaters to well over 1,000 mg per litre for salty sweaters. The calculator multiplies what you drink by how salty you sweat, so the sodium matches the fluid.

Worked example. A 4 hour 30 minute gran fondo, 75 kg rider, mild weather (sweat rate about 0.75 L/h), average saltiness, gut not specially trained:

Carbs: 75 g per hour, 338 g in total
Fluid: 550 mL per hour, about 2.5 L in total
Sodium: 500 mg per hour, 2,250 mg in total
Rhythm: every 20 minutes, about 25 g of carbs and 180 mL to drink

Turning grams into food

Read the label of what you use. As a guide:

Item	Typical carbs
Energy gel	20–40 g (25 g is common)
500 mL bottle of drink mix	30–80 g, depending on the mix
Energy bar	25–45 g
Banana	about 25 g
Rice cake (homemade, 100 g)	about 35 g
Handful of sweets or chews	20–30 g

A simple structure for long races is to get a base of carbs from your bottles and top up with gels or solid food at fixed times. Eat solid food early in the race and switch to gels and drink later, when intensity rises and chewing gets harder.

Want this worked out for you every day? LeCoach builds your training around your own numbers.

Try LeCoach for free

Training your gut

The single most effective thing you can do for race nutrition is to practise it. Your gut adapts to carbohydrate intake over a few weeks: absorption improves and stomach problems decrease. Start at around 40 to 60 g per hour on long rides and add about 10 g per hour each week until you reach your race target. Practise with the exact products and the exact rhythm you will use on race day. Our guide to gut training for cyclists explains the process.

Common mistakes

Trying something new on race day. New gels, new drink mix, new breakfast: all risky. Use only what you have tested.
Waiting until you are hungry. By then it is too late to absorb enough. Start in the first 20 to 30 minutes and eat on a schedule.
Drinking only water in a long hot race. Large amounts of plain water without sodium can dilute your blood sodium. Use an electrolyte drink.
Overdrinking. More is not better. Drinking more than you sweat can cause hyponatremia, which is dangerous.
Counting only gels. Your drink mix probably carries a lot of your carbs. Count everything.
Forgetting pre-race fuel. Eat 1 to 2 g of carbohydrate per kg of body weight 2 to 3 hours before the start.

When to change the plan

Heat: sweat rate rises sharply. Measure it with the sweat rate calculator in similar conditions, and enter it here.
High intensity: at race pace your gut tolerates less. Rely more on liquids and gels.
Short races: under an hour, focus on breakfast and a good warm-up; you do not need to eat during the race.
Running races: the gut is shaken more when running, so many runners tolerate less carbohydrate than they would on the bike. Train it the same way and lean on gels and drink rather than solid food.
Triathlon: do most of your eating and drinking on the bike, where it is easiest.

For a step-by-step approach, read build a race fueling plan and our guide to hydration and electrolytes. And when you pack, the race day checklist makes sure the bottles and gels actually make it to the start.

You can ask LeCoach how to fuel your race, and it answers from your own rides, body weight and race distance instead of a generic chart.

Sources

Jeukendrup AE. A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Medicine, 2014;44(Suppl 1):S25-S33.
Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine joint position statement: nutrition and athletic performance. Medicine and Science in Sports and Exercise, 2016;48(3):543-568.
Baker LB. Sweating rate and sweat sodium concentration in athletes: a review of methodology and intra/interindividual variability. Sports Medicine, 2017;47(Suppl 1):111-128.
Jeukendrup AE. Training the gut for athletes. Sports Medicine, 2017;47(Suppl 1):101-110.

Frequently asked questions

How many carbs per hour should I eat in a race?

For races of 1 to 2 hours, 30 to 60 g per hour. For 2 to 4 hours, 60 to 90 g per hour, using a glucose and fructose mix. For races over 4 hours, gut-trained athletes can take 90 to 120 g per hour. Under an hour, you do not need to eat during the race.

How much should I drink per hour while cycling?

Most riders do well with 400 to 1,000 mL per hour, depending on heat and sweat rate. A useful target is about 75 % of your sweat losses, so that you lose less than 2 % of body weight over the race. Measure your sweat rate to personalise it.

How much sodium do I need per hour?

Typically 300 to 600 mg per hour in normal conditions, and 600 to 1,000 mg or more in heat or for salty sweaters. The calculator multiplies what you drink by how salty you sweat, so sodium and fluid stay in proportion.

What is gut training?

Practising high carbohydrate intake during training so your gut adapts to absorb more with fewer problems. Start around 40 to 60 g per hour on long rides and increase by about 10 g per hour each week until you reach your race target.

Why mix glucose and fructose?

They are absorbed through different transporters in the gut. Glucose alone tops out at around 60 g per hour; adding fructose lets you absorb 90 g per hour or more. Most modern gels and drink mixes use a ratio of about 1:0.8.

What should I eat before a race?

A carbohydrate-rich, low-fat, low-fibre breakfast 2 to 3 hours before the start, about 1 to 2 g of carbohydrate per kg of body weight. Oats, white bread with jam, rice or a banana work for most athletes. Eat what you have tested in training.

How do I know if I sweat a lot of salt?

White salt marks on your kit or helmet straps after a ride, sweat that stings your eyes and a salty taste on your skin are signs of a high sweat sodium concentration. A sweat test gives an exact number, but those signs are enough to choose "salty" in the calculator.

How many gels per hour should I take?

It depends on your carb target and what else you eat or drink. Most gels hold 20 to 40 g of carbohydrate. At 60 to 90 g per hour, that is usually 2 to 3 gels an hour if gels are your only source, or 1 to 2 if your bottles carry a carb drink. Take them with water and spread them out, for example every 20 to 30 minutes.