Reinstalling Office after a reformat: Microsoft, bundled copies, free alternatives

How you get Office back depends on where you bought it. For most people it is an account sign-in; the cases that need a product key typed in again are few and specific.

Last updated 2026-09-22

Which kind is yours?

Before restoring, work out which form you had. For Word, Excel and PowerPoint it is one of the four below. If you are not sure, the product name on the File → Account screen of the old installation is the answer.

Microsoft 365 (subscription)

Paid monthly or yearly. At account.microsoft.com → Services & subscriptions, click Install; it installs under the signed-in account and activates. There is no product key. Up to five installs are allowed, so a reformatted PC counting again is no problem.

Perpetual licence (Office 2021, 2024 Home & Student and the like)

Bought once, used indefinitely. The product key was linked to a Microsoft account at first install, so the product appears under that account’s Services & subscriptions page and installs from there. No key to re-enter; the key card is only needed before it is linked.

Office that came with the PC

When the PC was first switched on, an Office activation screen asked for an account. The licence is under that account’s Services & subscriptions. If you do not know which account, try each email address you used at the time. This licence is bound to that PC and cannot move to another.

Office provided by your employer (Microsoft 365 Business, volume licence)

Sign in to office.com with the work account and there is an Install button. If IT installed it under a volume licence, you cannot restore it yourself — ask IT.

Restoring Microsoft Office

1. 1

   Sign in to the account

   account.microsoft.com → Services & subscriptions. If your Office appears there, you are halfway done. If not, it is a different account — the job is finding the account, not typing a key.

2. 2

   Click Install

   The installer does the rest. If asked 32-bit or 64-bit, choose 64-bit. Ten to thirty minutes depending on your connection.

3. 3

   Sign in on first launch

   Open Word and sign in with the same account to activate. If an activation wizard asks for a key, it was installed under the wrong account — check again.

4. 4

   Reconnect Outlook accounts

   If you used Outlook, add the accounts. Microsoft 365, Gmail and IMAP accounts pull mail from the server; POP3 mail or mail kept in a PST file needs the backed-up file opened.

5. 5

   Put templates and signatures back

   Normal.dotm, AutoCorrect entries, ribbon customisations and Outlook signatures live only on the PC. If you copied the Templates and Signatures folders under %APPDATA%\Microsoft before formatting, put them back in the same place.

Regional office suites

Hancom Office (Korea)

A Hancom Docs subscription signs in with the account; a perpetual version asks for the key again, found in the purchase email, the Hancom account’s order history or the card in the box. The free Hancom Office Viewer opens, prints and exports HWP files to PDF, which is enough if you only receive documents.

Office bundled with Japanese PCs

Japanese branded PCs commonly ship with a perpetual Office Home & Business. It is linked to the Microsoft account used at first setup and reinstalls from that account’s Services & subscriptions, the same as any perpetual licence.

Can a free suite replace it?

If there is no licence or it has expired, look at what you actually do before buying again. For opening documents and making the occasional change, free is often enough.

Office on the web (office.com, Google Docs)

With just a Microsoft account, Word, Excel and PowerPoint run free in the browser at office.com. Features are trimmed, but most documents open and edit without trouble. Nothing to install.

LibreOffice

The open-source suite. Opens and saves DOCX, XLSX and PPTX, and is free at a company. Documents with complex formatting or macros can shift slightly. Enough for personal documents and simple work files.

ONLYOFFICE

The free suite closest to Microsoft Office in look and file compatibility. Being DOCX-native, documents exchanged with Office users keep their layout better. Free at a company too.

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