How to SUM 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. Keep the inputs visible and clearly labelled and the whole thing stays auditable — anyone who opens the file later, including you, can see at a glance exactly what feeds the result and change one assumption without hunting through the formula. For “sum time in excel”, the reliable version is a short checking loop, not just the first command that appears to work. Run it on a deliberately small range first, watch how the affected cells change, and only then apply the same setup to the full sheet. 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 is what makes a workflow that saves repeating the same clicks every week useful in real work: repeatable, auditable, and not dependent on memory or luck.

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. Keep this page bookmarked for the next time the same question comes up. Better still, rebuild the example once in your own sheet — doing it yourself, with the tool above to check against, is what turns a copied formula into a technique you own. Here is the takeaway for “sum 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