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Instrument calibration due date calculator

Enter the last calibration date and the interval in months. The next due date is calculated in UTC date-only maths, so month-end dates clamp instead of rolling into the next month.

Calibration details

Use the date on the certificate, not the date the instrument arrived back on the bench.

The date on the certificate. Read as YYYY-MM-DD and shown that way in the result, whatever date order your browser uses.

1 to 120 months.

Optional. 30 by default.

Result

Current

Next calibration due

2027-11-10

ISO date, YYYY-MM-DD

Days remaining
365 days
Interval
12 months

Want the reminder sent for you?

CalRegister emails the lead times you choose and repeats while an instrument is overdue.

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This calculator is a planning aid, not a calibration record. It stores nothing and submits nothing. The date on the certificate and the procedure in your quality system remain authoritative.

How the due date is calculated

01

Add the interval

Next due is the last calibration date plus the interval in whole months.

02

Clamp the month end

31 Jan plus one month is 28 Feb, or 29 Feb in a leap year. 31 Mar plus one month is 30 Apr. The date never rolls into the next month.

03

Compare with today

The calculator counts whole UTC days. Due today is not overdue. Anything before today is.