Free calculator
Vial duration calculator
Estimate how many scheduled events and days your entered vial dose count covers. See the final event offset without assuming expiry or stability.
Free, no sign-up. Calculations stay in this page. Inputs are cleared when you leave or reload.
How the supply count works
Total portions = entered portions per vial × number of identical vials. Complete events = the total divided by portions per event, rounded down.
The last event is (complete events − 1) × interval days after the first event. One covered event therefore has a zero-day offset: it is the first event itself.
Does this tell me when a vial expires?
No. This is count-based schedule coverage, not a beyond-use date, expiry estimate, or guarantee of usable supply. Follow the product and pharmacy’s storage and beyond-use instructions.
Which schedules fit?
Only identical portions used at a fixed interval of whole days. Do not use it for changing amounts, several events per day, pauses, or cycles. It does not choose an interval or assume a start date.
If the available portion count is uncertain, confirm it before calculating. To keep the history separate from your plan, use the blank tracking template.