With melatonin, when you take it matters more than how much you take. This tool gives the window to take it before your target bedtime, based on the form you use. Enter the time you want to be asleep and pick your form.

How this works

The window is set back from your target bedtime by an amount that suits each form:

Standard tablet: 30 to 60 minutes before bed
Sublingual or dissolvable: 15 to 20 minutes before bed
Extended-release: at bedtime

For a 10:00 PM bedtime with a standard tablet, that means taking it between 9:00 and 9:30 PM. Melatonin usually starts working within 20 to 40 minutes, with its peak around an hour after you take it, which is why the window sits before bedtime.

Understanding your result

Melatonin works by signalling that it is time to sleep, not by forcing sleep, so getting the timing right is the main thing. On dose, health sources suggest starting low, around 0.5 to 1 mg, and many people do well on 1 to 3 mg. More is not better, and amounts above roughly 3 to 5 mg tend to add next-day grogginess without improving sleep. Dimming the lights after taking it helps, and jet lag or shift work may need different timing.

Important limitations

• This gives general timing for everyday sleep onset, not for jet lag, shift work, or circadian rhythm disorders, which use different schedules.
• Melatonin is not consistently effective for long-term insomnia, and good sleep habits matter more.
• Start with the lowest dose that helps, and check with a professional before using it regularly or giving it to children.
• Extended-release is designed for staying asleep and is usually taken at bedtime.

Scientific basis

The timing and dosing guidance here comes from these health authorities:

• Melatonin: What You Need To Know (US NIH, NCCIH)
• How and when to take melatonin (UK NHS)

This calculator is for general education only and is not medical or professional advice. Speak with a qualified professional about ongoing sleep problems or before giving melatonin to a child.