Pill supply calculator
How long will my pills last?
Divide the pills you have by the pills you take in a day. With 90 tablets at 1 tablet three times a day, that's 90 ÷ 3 = 30 days. Put your own numbers in below to get the day you run out and the day to reorder by.
Your pills last
30 days
This assumes you take every dose, the same amount each day, starting on the date above.
This is a counting tool, not medical advice. Follow your prescriber's instructions, and ask your pharmacist if you're not sure how much you take.
Doser, our medication reminder for iPhone, keeps this count for you as you take each dose.
Worked examples
Each row divides the pills you have by the pills you take in a day. A remainder smaller than a day's pills doesn't add a day.
| Pills you have | Each time | Times a day | Calculation | Lasts |
|---|---|---|---|---|
| 90 | 1 | 3 | 90 ÷ (1 × 3) | 30 days |
| 30 | 1 | 1 | 30 ÷ (1 × 1) | 30 days |
| 60 | 2 | 2 | 60 ÷ (2 × 2) | 15 days |
| 100 | 1 | 2 | 100 ÷ (1 × 2) | 50 days |
| 28 | 0.5 | 1 | 28 ÷ (0.5 × 1) | 56 days |
The same thing with dates
You start a new box of 90 tablets on March 1 and take 1 three times a day. The box covers 30 days, March 1 to 30, so March 30 is your last full day and you run out on March 31. To reorder a week early, do it by March 24.
When the dose isn't the same every day
A dose that goes up or down
If your dose changes in steps, such as a course that tapers, work out each step on its own: the pills the first step uses, then how long what's left lasts at the next dose.
Only when you need it
For a medicine you take as needed, there's no fixed daily amount, so any date is a guess. Entering the most you'd take in a day gives the earliest date you could run out.
A missed dose
Each missed dose makes the pills last a little longer than the calculator says. Count what's left, set the date to today and work it out again.
Let Doser keep the count
Working it out once is easy. Keeping it right every day is the part that slips. Doser, a medication reminder for iPhone, counts your pills down as you log each dose and tells you when it's time to refill.
- You pick when to hear about it, for example when 10 are left.
- A second heads-up comes 2 days before you run out, at one of your dose times.
- When the new box arrives, tap I got more and enter how many came.
For iPhone. An Android version is on the way.
Questions about running out of pills
- How do I calculate how many days my pills will last?
- Multiply the pills you take each time by the times a day, then divide the pills you have by that number. With 60 pills at 2 twice a day, you take 2 × 2 = 4 a day, and 60 ÷ 4 = 15 days.
- How early should I reorder my prescription?
- Ask your pharmacy or doctor's office how long a refill takes, then add a few days for weekends and holidays. It varies: one NHS region in England tells patients a prescription can take up to three days, or sometimes longer, to be ready. NHS North East and North Cumbria
- What if I take half a tablet?
- Enter 0.5 as the pills each time. 28 tablets at half a tablet once a day last 56 days. Only split a tablet if your prescriber or pharmacist has told you to.
- Can I make my pills last longer by taking fewer?
- Don't change how much you take to stretch a supply. If you'll run out before you can get more, call your pharmacist or doctor and ask what to do.
- Does it work for capsules and vitamins?
- Yes, for anything you take a set number of each time: tablets, capsules, vitamins or supplements. It doesn't work for liquids or creams.
Never work out the refill date again
Doser keeps the count as you take each dose and tells you before you run out.