Nutrition Calculator

Enter your hourly nutrition needs for either your bike or run, and specify the duration of the workout. Then choose which nutrition products you would like the calculation to be from and the calculator will tell you how many servings of each product you need.
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Nutrition is one of the most difficult parts of a triathlon and endurance events, and it takes time, experimentation, and usually a lot of trial and error to get it right. But it doesn’t all have to be guesswork.

We’ve put together a triathlon and endurance nutrition calculator to sum up the calories, carbs, sodium and more of whatever race fuels you plan on using. This nutrition calculator will help you optimize your endurance fueling.

Video on how to use the calculator

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Video on how to use the calculator

Here’s how to use it:

1. Estimate your race duration in hours and minutes. This should be just for the bike or the run (do them separately). Enter that into the calculator.

2. Determine your hourly requirements for sodium, water, calories, and carbohydrate.

Below are some guidelines. Keep in mind that everybody is different and these are just estimates. What you will actually need will likely be different and you will need to experiment to know. As always, test your fueling as you train to avoid any surprises on race day.

  • Calories: A good starting point is around 300-350 calories per hour, on the bike. If you’re bigger or smaller adjust accordingly.
  • Carbs: On the bike, you can start by aiming for .6 g carb/hour per pound of body weight, and half that on the run (.3 g of carb/hour per pound). So a 150 pound guy would need 90 g on the bike per hour and 45 g on the run, per hour. Here’s a video I did with nutritionist and triathlete James Bell on carbs.
  • Water: This one can vary tremendously depending on conditions. In a hot and humid race you may lose up two litres of water per hour, but it may not be possible to replace all of that. Check out this video all about hydration and sodium for more guidance.
  • Sodium: This nutrient is lost through your sweat, and knowing how much of it you lose per litre of sweat allows you to replace it as you lose it. Unlike water or calories, you indeed can replace it as fast as you lose it. If you have not been sweat tested, enter 1,000 mg per hour, or even 1,500 if the conditions are hot and humid. Here’s an explainer video I did on how to determine your sweat and sodium needs.

3. Enter the nutrition products you have and you intend on racing with. Start typing them in and if they’re in the database, select them. If they’re not in the database, you may add them (click on Add New Product), along with their nutritional data.

Please make sure to enter correct data as other athletes will be using it. Maybe you are not concerned about one or two of the nutritional fields, but please enter it anyway for the benefit of other athletes. Thanks.

4. Adjust the servings or dosage levels of each product until your nutritional figures hit your requirements (as established in step 1 above).

For example, change the number of gels from 1 to 3 or 4; change the other product servings from 1 to 3 or 4 as well, and watch the sums change.

The numbers will turn green when they are within 10% of your targets. They’ll turn yellow when within 15%; red beyond that. Keep adjusting them up and down until you find your ideal combo.

5. Download results so you have a record of what you need. You can save this in your phone or email as a reference and reminder of what you need to pack and prepare for your race.

Description of the table

Totals: This row shows the grad total sums of calories, sodium, carbs, etc. However, this number may not be very meaningful to you, as you may be more used to thinking in terms of hourly totals.

Per Hour: This row is the sum of the Totals (above) divided by the number of hours you input. So this is your hourly intake. You want this to match your hourly targets.

Targets: These are the hourly targets you set above. Ideally, the Per Hour figures will match these figures.

Let us know in the comments if you have any feedback or if there are missing products you’d like added, or email me here: .

Final note

You can use the same calculator on your mobile using the same URL. Or, you can download the IronHacks app as seen below. The databases are synched, but in the app you can save the results and tag them to a race.

You can view that race where you’ll see your nutriton plan along with your past finish times and planned finish times. You can also add a race packing checklist to future races.

Then, you’ll have the following easily accessible from the app:

  • Nutrition plan for a particular race
  • Planned race times for that race
  • Past race times (on that course, if you have done it before)
  • Packing checklist for that race

Get the nutrition calculator in our app:

Choose nutrition

Nutrition Guidance and Help

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  1. Its really a good tool. I just need to sort out my sodium n other mineral usage per hour. That’ll sort out my cramping issues, and help perform better.

    1. Idham, if you are dealing with cramping issues this is most likely a electrolyte deficiency. Magnesium is the #1 deficient electrolyte with endurance athletes. I am a mineral specialist and would suggest HydraMag Magnesium drink. No GI issues and can be combined with Sodium and Potassium to maximize the utilization of both.

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