Free calculator
How long does an inhaler last?
Enter the puffs left (from the dose counter or the box), puffs per dose and how many times a day. You get the number of days it lasts and when to order the next inhaler.
- Free, no sign-up
- Answer as you type
- Nothing you type is saved
Your supply lasts
50days
- Order the refill byFriday, 11 December 2026
- Last day coveredThursday, 17 December 2026
- In months, roughly1.6
- You use per day4
- Needed for 30 days / 90 days120 / 360
If you need your reliever inhaler more often than usual, talk to your doctor or nurse – don't just buy a new one sooner.
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
Guides on this topic
Medication Stock Records: Check Before You Rely on Them
A stock counter is an organisational estimate based on the information entered into it. A brief check helps you notice a mismatch before you rely on …
ReadMedication Adherence: Why Doses Get Missed and What Helps
Medication adherence means taking your medicines the way you and your doctor agreed – the right dose, at the right time, for as long as planned. Most…
ReadMedication List: Prepare for Your Next Appointment
A medication list is most useful when it is current, readable and easy to bring to an appointment. Use this checklist to organise what you already kn…
ReadHow many days is an inhaler?
Days = puffs left ÷ (puffs per dose × doses per day). Inhalers commonly hold 60, 120 or 200 puffs – the number is on the box.
- 200 puffs, 2 puffs twice a day = 50 days
- 120 puffs, 2 puffs twice a day = 30 days
- 60 doses, 1 dose twice a day = 30 days
For an inhaler you use regularly, the result is reliable. For a reliever you use only when needed, enter your usual puffs per day – and keep in mind that it can run out much faster in a bad week.
Using the reliever more often?
Needing a reliever more often than usual is worth telling your doctor or asthma nurse about, rather than just ordering a new inhaler sooner. Some inhalers also have to be primed again after a few days unused, which uses puffs – the leaflet explains it.
Never run out of puffs
Count inhaler puffs automatically
Set the stock in puffs
Doserra counts any unit, not just tablets.
Confirm each dose
Every dose comes off the count.
Get the refill reminder
Order the next inhaler before the counter hits zero.
Frequently asked questions
How long does a 200-puff inhaler last?
At 2 puffs twice a day, 50 days. At 2 puffs once a day, 100 days. Priming and extra puffs make it shorter.
How do I know how many puffs are left?
Most inhalers have a dose counter. If yours doesn't, keep a count of the puffs you use or let an app subtract them.
Can I keep using an inhaler after the counter shows zero?
No – the leaflet usually says to replace it then, as the remaining puffs may not contain the right amount of medicine.
Guides
Guides for everyday medicine routines
Practical advice on remembering doses, organising medicines and caring for someone else's.
A Weekly Medication Record Review in Five Checks
A weekly review is a short check of your information and tools. It is not a review of whether your treatment is right for you. Use it to find stale r…
ReadFamily Medication Profiles: Keep Each Person Separate
If you help more than one person, a clear boundary between their records is essential for everyday organisation. Profile names, separate lists and a …
ReadMedication Notes: Turn a Busy Week into Clear Questions
A week of scattered notes can be difficult to explain during a short appointment. A simple structure helps you describe what you noticed, when it hap…
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.