Install Office 2021 or 2019 with a Product Key

Last Updated: junio 1, 2026

What You Need Before You Start

Installing Microsoft Office is straightforward once you have the right pieces in place. Before diving into the steps, make sure you have:

• A matching Microsoft Office product key (25-character code, formatted as XXXXX-XXXXX-XXXXX-XXXXX-XXXXX)
• A Microsoft account (free to create at account.microsoft.com)
• A stable internet connection for downloading and activating
• At least 4 GB of free disk space (more recommended)

If you are still choosing a one-time Office version, start with the currently maintained Windows paths below:

• Office 2021 Professional Plus — the safer starting point when you want the newer one-time Office release for Windows.
• Office 2019 Professional Plus — keep this route for compatibility or when the 2019 release is intentional.
• Office key hub — compare the current Office 2021 and Office 2019 paths before checkout.

Step 1: Redeem Your Product Key

The first step is to link your product key to your Microsoft account. This is how Microsoft tracks your license and lets you download the installer.

For Office 2021

1. Open your browser and go to setup.office.com.
2. Sign in with your Microsoft account (or create one if you don’t have one).
3. Enter your 25-character product key and select your country/region.
4. Click Next. Your key is now linked to your account.
5. You’ll be redirected to your Microsoft account page where you can download Office.

For Office 2019

1. Go to setup.office.com.
2. Sign in with your Microsoft account.
3. Enter your product key.
4. Follow the prompts to redeem and download.

Note: Some Office 2019 Professional Plus keys may use a different activation route from setup.office.com. If your key is not accepted there, use the instructions delivered with your order or contact support before repeatedly retrying.

Step 2: Download Microsoft Office

After redeeming your key, you need to download the Office installer.

Method A: Download from Your Microsoft Account

1. Go to account.microsoft.com/services.
2. Find your Office product under “Services & subscriptions.”
3. Click Install → Install again to download the installer file.
4. The file (OfficeSetup.exe) will be saved to your Downloads folder.

Method B: Direct Download (Office 2021/2019 Professional Plus)

If you purchased a volume license key (common for Professional Plus editions), you may need to download Office using the Office Deployment Tool:

1. Download the Office Deployment Tool from Microsoft.
2. Create a configuration XML file specifying your Office version.
3. Run the tool to download and install Office.

For most users buying retail or Home & Business keys, Method A is all you need.

Step 3: Install Microsoft Office

1. Locate the downloaded OfficeSetup.exe file and double-click it.
2. The installer will begin downloading Office components. This may take 10–30 minutes depending on your internet speed.
3. You’ll see a progress bar — don’t turn off your PC or disconnect from the internet during this process.
4. Once complete, you’ll see a “You’re all set!” message.
5. Click Cerrar.

Office apps (Word, Excel, PowerPoint, etc.) will now appear in your Start menu.

Step 4: Activate Microsoft Office

After installation, you need to activate Office to unlock full functionality.

Automatic Activation

In most cases, if you redeemed your key at setup.office.com before installing, Office activates automatically when you:

1. Open any Office app (e.g., Word).
2. Sign in with the same Microsoft account you used to redeem the key.
3. Office detects your license and activates.

Manual Activation (If Needed)

If Office doesn’t activate automatically:

1. Open any Office app.
2. Click File → Account.
3. Look for the activation section. Click “Change Product Key” o “Activate Product.”
4. Enter your 25-character product key.
5. Click Activate.

If Online Activation Needs Another Route

If Office asks for a different activation method, do not keep trying random commands. Save the exact activation message, confirm the Office edition, and use the instructions delivered with your order. If the message still does not match, contact support with the order number and screenshot.

Troubleshooting Common Issues

“This product key has already been used”

This means the key is already linked to a Microsoft account. Sign in with the account that originally redeemed the key. If you just purchased the key, contact the seller for assistance.

“We couldn’t verify your product key”

Double-check that you’re entering the key correctly — watch for similar-looking characters (0 vs O, 1 vs I). Make sure you’re using the right redemption page for your Office version.

Office installs but won’t activate

• Ensure your internet connection is stable.
• Check that the product key matches the installed Office version (e.g., don’t use a 2019 key for Office 2021).
• Try signing out and back into your Microsoft account within the Office app.
• Run the Microsoft Support and Recovery Assistant to diagnose issues.

Previous version of Office is blocking installation

Uninstall any existing Office version before installing a new one:

1. Go to Settings → Apps → Installed apps.
2. Find Microsoft Office, click the three dots, and select Uninstall.
3. Restart your PC, then install the new version.

Which Office Version Should You Install?

If your goal is a one-time Office install on Windows, keep the choice narrow: Office 2021 is the newer route, while Office 2019 is mainly a compatibility or budget route for older setups.

• Office 2021 Professional Plus: the better starting point for most Windows users who want a current one-time Office release. View Office 2021 Professional Plus
• Office 2019 Professional Plus: useful when you intentionally need the 2019 release for an older workflow or compatibility reason. View Office 2019 Professional Plus

For a side-by-side decision, use the Office 2021 vs Office 2019 comparison. If you are still choosing, the Office keys hub keeps the current Office 2021 and Office 2019 paths in one place.

Support note: Microsoft lists Office 2021 support through October 13, 2026. Microsoft lists Office 2019 extended support as ended on October 14, 2025, so use Office 2019 only when that older release is intentional.

Get the Right Office Product Key

Use the live product page as the source of truth for the current product, delivery note, and activation-support path. Do not buy a second key until you have checked whether your issue is edition fit, account sign-in, or a redemption-page mismatch.

View Office 2021 Professional Plus
View Office 2019 Professional Plus

Frequently Asked Questions

Can I install Office without a Microsoft account?

Most setup.office.com redemptions use a Microsoft account so the license can be tied to the account and downloaded again later. Some Professional Plus installs may use a different activation route. If setup.office.com does not accept your key, follow the instructions delivered with your order or contact support before repeatedly retrying.

Can I install Office on multiple computers with one key?

A one-time Office key is normally for one device or one active install unless the product terms say otherwise. If you need Office on several devices, compare a separate key for each device with Microsoft 365.

How do I find my Office product key after purchase?

Check the order email first, including spam or promotions folders. If the key was redeemed through a Microsoft account, also check Services and subscriptions.

Does Office 2021 still work in 2026?

Yes. Office 2021 still works in 2026, and Microsoft lists Office 2021 support through October 13, 2026. Office 2019 can still open on many existing PCs, but Microsoft lists Office 2019 support as ended on October 14, 2025.

What should I check if Office will not activate?

Check the Office version, product-key entry, Microsoft account, internet connection, and whether another Office version is already installed. If the activation message is unclear, save the exact wording and contact support before buying another key.