How to Add Time in Excel

What this does

Excel stores a time as a fraction of a day: 6:00 is 0.25, 12:00 is 0.5. Adding times is therefore ordinary arithmetic, and the whole difficulty is display. The standard h:mm format shows a clock time, so a total of 30 hours displays as 6:00 — it has silently dropped the whole day. The custom format [h]:mm tells Excel to let the hours accumulate past 24. To convert a time total into a decimal number of hours for a rate calculation, multiply by 24: =SUM(B2:B20)*24 formatted as a plain number gives 30.5, which times an hourly rate gives money. Times crossing midnight need =B2-A2+(B2<A2) so the negative half-day is corrected. The same idea underpins a lot of everyday Excel work, so the few minutes spent getting it right here pay back across every sheet you build afterwards. Treat it as a pattern, not a one-off, and it stops being something you look up and starts being something you reach for. Treat “add time in excel” as a small repeatable workflow rather than a one-off click you hope to remember next time. Use a small test block before the live file, so any surprise in the affected cells shows up while it is still harmless. When a formula is involved, keep the inputs labelled beside it, reference cells instead of typing values, and apply number formatting only after the result checks out. That turns a layout choice that keeps the sheet readable and sortable into a method you can reuse, explain, and defend when the workbook leaves your screen.

A worked example

Daily hours in B2:B8 as 7:30, 8:15, 6:45, 8:00, 7:45, 4:30, 0:00. =SUM(B2:B8) with the default h:mm shows 18:45, which is wrong — the true total is 42:45. Select the cell, press Ctrl+1 ▸ Custom, enter [h]:mm, and it reads 42:45. For pay at €18.50/hour: =SUM(B2:B8)*24*18.5 formatted as currency gives €790.88. A shift from 22:00 to 06:00 is =B2-A2+(B2<A2) → 8:00, where a plain subtraction returns ####. Timesheets, shift totals and project hours all go wrong in the same two places — the 24-hour wrap and the missing ×24 — and both are one formatting decision away from correct. A practical tip before you scale it up: build it once on a small block of test data, confirm the number against the tool on this page, and only then point it at your real sheet. That one habit catches almost every mistake while it is still cheap to fix, long before a wrong figure reaches a report or a colleague.

In Google Sheets

If you are in Google Sheets rather than Excel, the good news is that the formula shown here is identical and the workflow barely changes — menus sit across the top instead of in a ribbon, and a few function names differ slightly, but anything you build here moves across with little or no rework. Nothing on this page is behind a login: the tool runs entirely in your browser, the formula is shown in full with one-click copy, and the steps work the same on Windows and Mac. That is the whole promise here — the exact answer, a way to prove it on your own numbers, and just enough context to make it stick. Here is the takeaway for “add time in excel”: copy the answer if you are busy, but if you have a spare few minutes, rebuild the example in Excel yourself with the tool above open beside it. That single pass — type it, run it, watch the result move when you change an input — is what turns a formula you found into a technique you trust. Keep your inputs labelled and referenced, never hard-coded, and the same sheet stays correct and auditable as it grows. Done that way, you will not need to look this up again, and you will be the person others ask.

Common mistakes

• Leaving the total in h:mm, which wraps at 24 hours and quietly under-reports the week.
• Typing 7.30 instead of 7:30, which Excel stores as the number seven-point-three, not seven and a half hours.
• Multiplying a time total directly by an hourly rate without the ×24, which produces a figure about 24 times too small.
• Subtracting an end time from a start time across midnight and getting ####, the display of a negative time.
• Mixing text entries like "8 hrs" into the column, which SUM ignores without warning.

Frequently asked questions