Free calculator
Refill calculator: when will my pills run out?
Enter what's actually in the bottle and how you take it. You get the number of days it covers, the last covered day and the date to order your refill by – plus how many you need for 30 or 90 days.
- Free, no sign-up
- Answer as you type
- Nothing you type is saved
Your supply lasts
30days
- Order the refill bySaturday, 14 November 2026
- Last day coveredFriday, 20 November 2026
- You use per day2
- Needed for 30 days / 90 days60 / 180
Counting the start day as day 1 and assuming every dose is taken as planned.
This calculator does arithmetic on the numbers you enter. It doesn't replace the instructions on your prescription label or the advice of your pharmacist or doctor.
Doserra keeps this count for you: every dose you confirm comes off the stock, and you're reminded to refill before you run out. Try it free
How to calculate days of supply
Days of supply = tablets on hand ÷ (tablets per dose × doses per day). With 60 tablets, one tablet per dose and two doses a day you use 2 a day, so the pack lasts 30 days. If you start today, today is day 1 and day 30 is the last day covered.
For "every other day" medicines use 0.5 doses per day; for half a tablet per dose use 0.5 tablets per dose. For something you take only when needed, use the number you typically take in a day – the result is only as good as that average.
Why the order-by date matters more than the run-out date
The run-out date tells you when you'd have a problem; the order-by date tells you when to act so you never have one. A buffer of about a week covers a weekend, a public holiday and a pharmacy that has to order the medicine in. If the next pack needs a new prescription or an appointment, leave more.
Any date drifts the first time a dose is skipped or doubled. Counting what's physically left – or letting an app subtract each confirmed dose – keeps the estimate honest.
Stop recounting
Let Doserra keep the count for you
Enter your stock once
How many tablets, capsules or doses you have right now.
Confirm each dose
Every dose you mark as Taken comes off the count.
Get the refill reminder
Doserra warns you when stock falls below your threshold – a free feature.
Frequently asked questions
How many days ahead should I order a refill?
Around a week for most once- or twice-daily medicines. Leave more if the refill needs a new prescription, a review appointment or a special order at the pharmacy.
How many tablets do I need for 30 days?
Multiply the tablets you use per day by 30. Two tablets a day means 60 tablets for 30 days and 180 for 90 days – the calculator shows both.
Why does the calculator count today as day 1?
Because you'll usually take today's doses from the tablets you just counted. If you've already taken today's doses, set the start date to tomorrow.
Does having tablets left mean I can get a refill?
Not necessarily. Some prescriptions have a limited number of repeats or need a review first. Check with your pharmacy when you reach your order-by date.
Guides
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ReadNever wonder again whether you took your medicine.
Add a medicine in a minute and Doserra reminds you at every dose, keeps the history and warns you before it runs out. Free for 2 medications, no account.
Doserra is available for iPhone and iPad. Scan the code or open this page on your iPhone.