Melatonin Dosage Calculator

Estimate an age- and weight-based melatonin starting dose and reference range, with timing based on whether you are using it for sleep onset, jet lag, or shift work.

Quick Facts

Core principle
Start low, go slow
Lower starting doses are often just as effective as higher ones for sleep onset, with fewer next-day effects.
Regulatory status
Sold as a dietary supplement
In the US, melatonin is not FDA-regulated as a drug, so labeled strength can differ from actual content between brands.
Best timing
30 to 60 minutes before bedtime
Taking melatonin close to the target bedtime lines up with the body's natural evening rise in melatonin.

Your Results

Calculated
Suggested starting dose
-
Rounded to typical tablet/liquid steps
Typical reference range
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Age- and weight-adjusted band
Recommended timing
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Based on purpose of use
Usage note
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Duration / follow-up guidance

Ready

Enter age, weight, purpose, and experience level, then calculate a suggested starting range.

About the melatonin dosage calculator

Melatonin is sold over the counter as a dietary supplement in the United States, so unlike a prescription drug it does not carry a single FDA-set dosing table. This calculator instead applies the starting-dose ranges commonly published by sleep-medicine sources, banded by age, lightly adjusted for body weight in children and teens, and shifted toward the low end for first-time or sensitive users. It is an educational estimate, not a prescription, and it does not replace guidance from a pediatrician, physician, or pharmacist.

How the estimate is built

The calculator starts from an age-band reference range (for example, roughly 0.5 to 3 mg for adults, smaller amounts for young children, and lower amounts for older adults) and, for ages under 18, scales that range slightly using body weight relative to a typical reference weight for the band. It then applies the "start low, go slow" principle: first-time or sensitive users are pointed toward the low end of the range, while regular users see a suggestion nearer the middle. Purpose of use changes the timing and duration guidance — sleep onset points to 30 to 60 minutes before bedtime, jet lag points to the destination bedtime and factors in the number of time zones crossed, and shift work points to the daytime sleep period after a night shift.

Interpreting the result

  • The suggested starting dose is rounded to common tablet, capsule, or liquid increments; the reference range shows the wider band the starting dose was drawn from.
  • Individual response to melatonin varies with age, body weight, liver metabolism, and other medications, so the same input numbers will not suit everyone.
  • Doses above roughly 5 to 10 mg are rarely shown to work better than lower doses for sleep onset and are more likely to cause next-day grogginess.

Important disclaimer

This tool performs general educational arithmetic only and does not constitute medical advice. Do not use it to diagnose, treat, or manage a sleep disorder, and always check with a pediatrician or healthcare provider before giving melatonin to a child or combining it with other medications.

Frequently Asked Questions

How is a melatonin starting dose determined?
This calculator applies commonly published sleep-medicine starting-dose ranges by age band, adjusted for body weight in children and teens, then favors the low end of the range for first-time or sensitive users. It is a general educational estimate, not a prescription.
What is a typical adult melatonin dose for sleep?
Sleep-medicine sources commonly suggest starting low, often in the 0.5 to 3 mg range taken 30 to 60 minutes before the target bedtime, and increasing only if needed, since higher doses are not consistently more effective for most adults.
How much melatonin is typically used for a child?
Pediatric sleep guidance generally uses smaller amounts than adult dosing, often starting around 1 mg for school-age children and adjusted for body weight, and should be discussed with a pediatrician before regular use.
Does melatonin dosing change for jet lag or shift work?
For jet lag, melatonin is generally timed to the destination bedtime rather than scaled up in amount, often continued for a few days after arrival, especially eastward across multiple time zones. For shift work, the same age-based amount is instead timed before the daytime sleep period.

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