How to Insert Date and Time in Excel

What this does

TODAY returns the current date; NOW returns the date with the time attached. Both are volatile: they recalculate whenever anything in the workbook changes, so a cell holding =TODAY() is not a record of when something happened, it is always "now". That is the single most consequential thing to know about them — a timestamp meant to stay put must be entered with Ctrl+; (date) or Ctrl+Shift+; (time), or pasted as a value. Their genuine use is anything that should move with the calendar: ageing an invoice, counting days remaining, driving a conditional format for overdue rows. 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 “insert date and 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

Days a receivable has been outstanding: =TODAY()-A2, formatted as a number rather than a date. Flagging overdue rows with conditional formatting: =AND(A2<TODAY(), B2<>"Paid"). Days remaining until a deadline: =A2-TODAY(). A static stamp instead — press Ctrl+; which types the date once and never changes it. TODAY and NOW are what make an ageing report age itself — and knowing they are volatile is what stops them being used as timestamps. One habit worth forming early: name the cells that hold your inputs, so the formula reads in plain language instead of a string of cell addresses. A reviewer — or you in three months — can then follow the logic without decoding what B7 and D2 were supposed to mean, which is most of what makes a sheet maintainable.

In Google Sheets

Google Sheets handles this almost identically to Excel. The formula syntax above is the same, and the menu lives under a slightly different label rather than a ribbon tab. Use the platform toggle at the top of the page to switch every keyboard shortcut between Windows and Mac, and expect at most cosmetic differences in naming. 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. If you take one thing from this page on “insert date and time in excel”, make it the habit rather than the keystrokes: set the problem up with labelled inputs, reference those cells, and let Excel do the recomputing. Bookmark the page for the syntax, but do the example once in a blank sheet and check it against the tool above — five minutes of hands-on practice fixes the method in memory far better than re-reading, and it surfaces the small snags while they are still harmless. After that the technique is genuinely yours: faster than searching for it again, and reliable enough to drop into work that other people depend on.

Common mistakes

• Using =TODAY() as a record of when something was entered, which rewrites itself every time the file opens.
• Formatting a date difference as a date, which shows 1900-01-15 instead of 14 days.
• Forgetting the brackets; =TODAY without them returns #NAME?.

Frequently asked questions