Free tool

Energy availability

Calories on their own cannot tell you whether a camp is working. This is the number that can.

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Percent. An estimate is fine: calipers, a scan, or your best guess from experience.
Kilocalories per day, averaged across the week.
Averaged across the week, including rest days. Two hard sessions on 4 days and nothing on three is about 120 minutes a day.
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kcal per kg fat-free mass per day

0304560+
Fat-free mass
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What the number is divided by
Training cost
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Subtracted before the division
Left after training
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Runs everything else
Estimated RMR
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Cunningham equation
How to read this

Energy availability is what remains after training is paid for, expressed per kilogram of fat-free mass. Below 30 is classified as low. Between 30 and 45 is moderate risk. At 45 and above there is no risk on this measure.

Those thresholds were established in female athletes. Male-specific values have not been determined, and the female cut-points are applied in male studies for want of anything better. Read your number with that in mind.

Every input here is an estimate, and body fat is the roughest of them. Treat the result as a direction rather than a verdict, and re-run it when something in the camp changes.

Why this number and not calories
Two thirds of one boxing cohort were below the threshold in ordinary training. A world champion finished fight week at 8.8. What the research says and what to do about it.
Read the article
When the number stays low
What low energy availability actually does across hormones, bone and immunity, why the first sign is rarely the one people look for, and when it stops being nutrition and becomes medicine.
Read the article
Free checklist, and one email a month if you want it
14 questions to answer before you sign a bout agreement
The weight terms and the anti-doping terms, in the order I go through them. Three pages, free to download, and one email a month if you want it.
Download the checklist (PDF)Get the monthly email

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Educational tool, not medical treatment or an individual nutrition prescription. For adults 18+. Estimates only. Sustained low energy availability carries real risks to bone, hormonal, immune and cardiovascular health. If your result is low, the answer is to eat more; training less on its own does not fix it. If tracking food affects your relationship with eating, speak to a physician or a registered dietitian.