Product key format checker
Paste a Windows or Office key to check its format (25 characters, 5 groups) and spot typos before you activate. Your key never leaves your browser.
Paste a key to check it.
This tool only checks the format. Whether a key activates can only be confirmed by Microsoft during activation — see the Activation helper.
Common typing mistakes
- 0 vs O, 1 vs I, 5 vs S, 8 vs B — Microsoft keys never use O, I, S, 0, 1 or 5, so these are always typos.
- Copy-paste the key from My Licence Keys instead of typing it.
- Dashes are optional — Windows and Office accept the key with or without them.
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