Calibration log template: the columns an auditor will ask about

Most machine shops track gauge calibration in a spreadsheet, and for many of them that is the right tool. The trouble is that most calibration spreadsheets answer "when was this calibrated?" when the questions that matter are "what comes due next month, whose box is it in, and what was it checked against?"

This guide gives you a template that answers those: two tabs, the columns for each, three formulas, and a fifteen-minute weekly routine. It works in Excel or Google Sheets.

Two tabs, not one

The most common mistake is one row per gauge with the latest calibration typed over the last one. That loses the history, and the history is what an auditor samples. Use two tabs:

• Master list: one row per gauge, showing its current state. This is what you print for the auditor and sort every week.
• Calibration history: one row per calibration event, never edited. A correction is a new row with a note saying which row it replaces.

Master list columns

If your columns have other names today, keep them. "Gage No", "Assigned to" and "Cal Date" work as well as the names above, as long as each column holds one kind of thing.

Calibration history columns

As found and as left are the two columns most homemade logs leave out, and the two an auditor is most likely to ask about. As found tells you whether the gauge was good while it was in use. As left tells you the state it went back to the floor in.

The three formulas

Assuming on the master list the interval in months is in column H, the last calibration date in L and the next due date in M, starting at row 2.

Next due, from the last calibration plus the interval:

=IF(L2="","",EDATE(L2,H2))

Days left until it is due:

=IF(M2="","",M2-TODAY())

Due status, with 30 days as the recall window:

=IF(M2="","No date",IF(M2<TODAY(),"Overdue",IF(M2-TODAY()<=30,"Due soon","Current")))

If a lab certificate states its own due date, type that date over the formula in that row and add a note, so the sheet does not quietly recalculate it. Format date columns as dates. Dates pasted in as text will make the formulas return errors; re-enter them as dates.

Formatting that does the looking for you

• Conditional formatting on the due status column: red for Overdue, amber for Due soon.
• A filter on Status so out-of-service and retired gauges drop out of the sort.
• Freeze the header row and the Gauge ID column.
• Sort by Days left, smallest first, every time you open the sheet.

A weekly routine

Fifteen minutes, the same morning every week:

1. Sort the master list by days left.
2. For every Overdue row: find the gauge. If it is still in use, pull it from service until it is calibrated.
3. For every Due soon row: email or tell the owner which gauges you need back and when.
4. Enter every calibration done last week as a new history row, then update Last calibration on the master list.
5. Check anything out at the lab longer than you expect. Labs usually return the certificate with the instrument, but not always.
6. Look for any as-found "out of tolerance" in last week's rows, and make sure someone has looked at what was measured with that gauge since its last good calibration.

Where the spreadsheet runs out

The template works for as long as one person runs the routine every week. It does not email the gauge owner, it does not stop a gauge being used past its due date, and the certificate PDFs end up in an inbox rather than next to the row. If your list is long enough that the routine slips, that is the point to look at a tool. Our gage calibration software guide has a checklist for comparing them.

Gauge Recall reads a spreadsheet laid out like this one. Paste the cells from Excel or upload a CSV, and its importer matches headers such as Gauge ID, Serial, Assigned to, Interval, Last Cal and Next Due, then shows every row with anything it could not read before saving. From then on, the Monday emails do the weekly routine's reminding for you.