Free calculator
How many months will my tablets last?
Enter how many tablets you have and how you take them. You get the supply in months and days, the last day it covers and the date to order the next one.
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Your supply lasts about
5.9months
- Order the refill byTuesday, 20 April 2027
- Last day coveredMonday, 26 April 2027
- Days covered180
- You use per day1
- Needed for 30 days / 90 days30 / 90
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
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ReadTablets to months
Months = tablets ÷ tablets per day ÷ 30.4 (an average month has 30.4 days).
- 90 tablets at 1 a day ≈ 3 months (90 days)
- 180 tablets at 1 a day ≈ 5.9 months (180 days)
- 180 tablets at 2 a day ≈ 3 months (90 days)
- 100 tablets at 1 a day ≈ 3.3 months
A "3-month supply" is usually counted as 90 days, so it runs out a few days before three calendar months are over. If refills are timed to the calendar, that gap adds up – order by the date shown, not by the month.
Days are more precise than months
Pharmacies and prescriptions count days of supply. Use the months figure to plan, and the order-by date to act. Your prescription and the leaflet set how the medicine is taken; the calculator only divides what you enter.
Stop recounting
Let Doserra keep the count for you
Enter your stock once
How many tablets you have right now.
Confirm each dose
Every dose you mark as Taken comes off the count.
Get the refill reminder
Doserra warns you before you run out – a free feature.
Frequently asked questions
How many months is 180 tablets?
At one tablet a day, 180 days – about 5.9 months. At two a day, 90 days, about 3 months.
How many months is 90 tablets?
At one a day, 90 days, just under 3 calendar months. At two a day, 45 days, about 1.5 months.
Is a 3-month supply 90 days?
Usually, yes. Three calendar months are 89–92 days, so a 90-day supply can run out a day or two before the date you expect.
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.
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