How this instrument works
Two separate guidelines cover added sugar, and this page reports both. The American Heart Association sets a fixed daily cap regardless of how many calories someone eats: 36 grams for men, 25 grams for women. Separately, a broader guideline — reflected in World Health Organization and USDA Dietary Guidelines advice — caps added sugar at 10% of total daily calories, converted to grams by dividing by 4, since sugar, like any carbohydrate, carries 4 kcal per gram.
The two guidelines measure different things and were built for different purposes. The AHA's cap is sex-specific and calorie-independent, aimed at limiting added sugar's contribution to cardiovascular risk regardless of how much someone eats overall. The WHO's 10% figure, from its 2015 guideline on sugars intake, is calorie-proportional and applies the same percentage to everyone, adult or child, scaling with energy needs; the WHO further notes that cutting added sugar below 5% of calories brings additional benefit, though 10% is the firm recommendation.
The two figures do not always agree, and which one binds depends on how many calories someone eats. At lower calorie levels the 10%-of-calories guideline often comes out below the AHA's fixed cap, making it the stricter number; at higher calorie levels the relationship flips, since the AHA cap does not grow with intake but the 10% figure does. Neither guideline is a target to eat up to — both describe an upper bound, not a recommended intake.
- Set Sex to male or female — it selects the AHA's fixed cap (ahaCapG): 36 g or 25 g.
- Enter Daily calories (kcal) — a reasonable estimate of total energy intake for the day is enough.
- Read the AHA added-sugar cap (ahaCapG) in grams, unaffected by the calorie figure.
- Read the 10%-of-calories guideline (guidelineG) in grams, which rises and falls with the calorie figure.
- Compare the two figures: whichever is lower is the stricter limit at that calorie level.
Worked example — 2000, 1800, and 3000 kcal/day
A man eating 2000 kcal a day: the AHA cap is fixed at 36 g. The 10%-of-calories guideline: 10% of 2000 kcal is 200 kcal, and 200 divided by 4 kcal per gram gives 50 g. Here the AHA's 36 g is the stricter of the two, sitting below the 10% figure's 50 g.
A woman eating 1800 kcal a day: the AHA cap is fixed at 25 g. The 10% guideline: 10% of 1800 is 180 kcal, divided by 4 gives 45 g. Again the AHA's 25 g is the tighter limit, well below the 45 g the percentage-based guideline would allow.
A man eating 3000 kcal a day: the AHA cap stays fixed at 36 g, since it never moves with calorie intake. The 10% guideline keeps scaling, though: 10% of 3000 is 300 kcal, divided by 4 gives 75 g. The relationship has now flipped — the AHA's fixed 36 g sits far below the 75 g the 10% rule would permit, making the AHA figure the binding, stricter cap at this higher calorie level.
Questions
Which added-sugar guideline should I actually follow?
Whichever is lower at your own calorie intake, if the goal is the stricter, more cautious limit — this page computes both so you can see which one binds. Many clinicians default to the AHA's fixed cap (36 g for men, 25 g for women) since it does not require tracking total calories precisely, while the 10%-of-calories guideline scales more naturally for people who already track intake.
Why does the AHA cap not change with calorie intake?
Because the AHA's recommendation targets a fixed amount of added sugar linked to cardiovascular risk, independent of how many calories a person eats overall — 36 g for men and 25 g for women, full stop. That differs in kind from the WHO's or USDA's percentage-based approach, which scales the sugar limit up or down with total energy intake.
At what calorie level do the two guidelines cross over?
For men, the 10%-of-calories guideline equals the AHA's fixed 36 g cap at 1440 kcal a day (36 × 4 ÷ 0.10); below that calorie level the AHA cap is the looser of the two, and above it the AHA cap becomes the stricter, binding limit. For women, the crossover sits at 1000 kcal a day, using the 25 g fixed cap.
Does added sugar include sugar naturally found in fruit or milk?
No — both guidelines here concern added sugar specifically: sugars and syrups added during processing or preparation, not the sugars naturally present in whole fruit, vegetables, or plain dairy. The WHO's broader 'free sugars' definition does fold in honey, syrups, and fruit juice, but excludes sugar intact inside whole fruit.
Is 10% of calories from added sugar considered healthy?
It is the WHO's upper limit, not a target to reach — the same 2015 guideline notes that cutting added sugar further, below 5% of total calories, brings additional health benefit. Ten percent is the firm recommendation; lower is described as better, not merely acceptable.
Do these guidelines apply the same way to children?
The percentage-based guideline does — WHO's 10%, and preferably under 5%, of calories applies across both adults and children. The AHA's fixed-gram figures on this page are adult numbers; the AHA publishes separate, lower absolute limits for children, since children eat fewer total calories and carry different cardiovascular risk profiles.
References
- American Heart Association — Added Sugars
- WHO — Guideline: Sugars Intake for Adults and Children (2015)
Read this first: This instrument computes a screening figure from population formulas — it is not a diagnosis, and it cannot see the whole picture a clinician can. Use it to inform a conversation, not to replace one.