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Hyrox carb loading. Most of you can skip it.

Enter your target finish time. You get a day-by-day answer, a race-morning meal timed to your wave, and in-race grams per hour, with the study behind every number, including the ones that disagree with us.

  • Keyed to your finish time, not a race distance
  • Every number shows its source
  • Counter-evidence shown, not buried
  • Free, and you see your plan without signing up

Racing a marathon or an ultra instead? Endurance carb loading calculator.

hrmin

Your best guess. It decides whether you need to load at all.

Anchors your race-morning meal to a clock time.

Your verdict

No carb load needed

Under 90 minutes, topping off and fuelling race morning beats a three-day load you don't need.

The day before

No load needed

No carbohydrate load is indicated for an event under 90 minutes. Eat a normal, carb-forward day - there is no supercompensation protocol to run. The three-day load you may read about elsewhere is drawn from marathon-length events.

Source: ACSM/AND/DoC position stand, 2016 · PMID 26920240

Race morning

The meal that matters

82–327g carbs

1–4 g/kg, 1–4 h before the gun

Source: ACSM/AND/DoC position stand, 2016 · PMID 26920240

  • Lean toward the higher end (nearer 4 g/kg) if you have 3-4 hours before the gun; the lower end (1-2 g/kg) if you'll eat closer to ~1 hour out.
  • Low fibre, low fat. Both slow gastric emptying and raise GI risk under race intensity.
  • Familiar food only. Race morning is not the day to try something new.

During the race

In-race fuel

~30g carbs / hr

Source: Jeukendrup, Sports Medicine, 2014 · PMID 24791914

Fluid

Drink to thirst; keep losses under 2% of body mass (about 1.6 kg for you).

Source: ACSM fluid position stand (Sawka et al.), 2007 · PMID 17277604

Sodium

Sweat sodium varies widely between people (roughly 10-70 mEq/L). For a sub-two-hour effort in normal conditions, a sports drink covers most athletes; heavy or salty sweaters can add a pinch more. Individualise rather than chase a fixed number.

Source: ACSM fluid position stand (Sawka et al.), 2007 · PMID 17277604

singles · practical guidance

Singles athletes move almost continuously with little built-in recovery. Realistically you'll take little to nothing in-race at this duration, so getting race-morning fuelling right matters more.

Where these numbers come from

No study has measured muscle glycogen in a Hyrox race. These targets are carried over from running, cycling, soccer, and rugby research and applied to Hyrox's format. Treat them as a reasoned starting point, not event-specific data.

  • Starting point, not prescription. Individual response varies with training history, gut tolerance, sweat rate, and the day's conditions.
  • If you haven't practiced an intake in training, don't debut it on race day. GI trouble costs more time than slightly under-fuelling.

Race mornings start early. We'll send the timing plan to your inbox so it's on your phone when you need it.

Race day is a small lever. What moves a Hyrox result is how you ate through the training block, which is the part nobody builds a calculator for. That's what we're building with Mero.

Read next

Hyrox fueling, worked out in practice.

The full race-day framework this calculator is built on, from the day before through the start line.

FAQ

Hyrox fueling, answered.

Do I need to carb load for Hyrox?
Probably not. Carbohydrate loading exists to supercompensate muscle glycogen for events long enough to deplete it, and the guidance threshold sits around 90 minutes (Thomas et al. 2016). Most Hyrox finishes come in under that. What matters more at this duration is arriving with topped-off glycogen and eating a proper race-morning meal. If you expect to finish over about 90 minutes, a moderate load becomes defensible.
How many carbs should I eat before Hyrox?
On race morning, 1 to 4 g per kg of bodyweight, 1 to 4 hours before your wave, low in fibre and fat (Thomas et al. 2016). For an 80 kg athlete that's roughly 80 to 320 g depending on how long you have. The day before, if you're finishing under about 90 minutes, eat a normal carb-forward day. There's no evidence a multi-day loading protocol helps at that duration.
Is carb loading different for Hyrox doubles?
The dose isn't, and we won't invent a number nobody has measured. What genuinely differs is logistics: in doubles and relay you get real rest while your partner works, so you can drink and take carbs mid-race in a way a singles athlete largely can't. Doubles finishes also tend to come in well under 90 minutes, which puts most teams firmly in the no-load band.
What should I eat the morning of a Hyrox?
A familiar, low-fibre, low-fat carbohydrate meal at 1 to 4 g per kg bodyweight, 1 to 4 hours before your wave (Thomas et al. 2016). Nothing new on race day. Because Hyrox waves are assigned and often early, timing is usually the harder problem than the food. Work backwards from your wave, not from when you'd normally eat.
Should I take gels during a Hyrox?
For a sub-75-minute race, probably not much. At that duration a carbohydrate mouth rinse has a measurable performance benefit without swallowing anything (Carter et al. 2004), and the evidence that in-race carbs improve short intermittent efforts is limited. Between roughly 75 minutes and 2.5 hours, 30 to 60 g per hour is the supported range (Jeukendrup 2014). Whether you can physically take it mid-race is a separate question in singles.
Will carb loading make me heavier for Hyrox?
Stored glycogen binds water, so a full load adds bodyweight (Olsson and Saltin 1970). In an event where you carry and move your own bodyweight through burpee broad jumps, wall balls and the runs, that's a real cost, and at sub-90-minute durations you'd be paying it for a glycogen benefit the evidence doesn't support.

Also in the calculators

Racing a distance event? Endurance carb-loading calculator. For weekly training macros, the hybrid athlete macro calculator.

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