To activate a Steam key, open the Steam client, sign in, open the Games menu and choose Activate a Product on Steam..., then follow the on-screen instructions. Steam Support also gives a browser page where you can register the key without the client. Once the key is registered, the game belongs to that Steam account and the key can't be registered again.
How to activate a Steam key in the Steam client
These are the steps Steam Support gives on its page "Activating a Product on Steam", with one step added at the start for a key bought online.
- Copy the key from your order page or email. Copy it, don't retype it.
- Launch the Steam client and log in to the Steam account that should own the game.
- Click the Games menu at the top of the Steam client.
- Choose Activate a Product on Steam...
- Follow the on-screen instructions and paste the key when Steam asks for it.
Steam's "Retail CD Keys" page describes a second way into the same window: the + Add a Game button at the bottom left of the client, then Activate a Product on Steam.... Both lead to the same place.
Other ways to activate
In a browser
Steam Support's activation page has a section called Register through browser. Its link opens store.steampowered.com/account/registerkey. When we opened that address without being signed in, Steam sent us to its sign-in page first. So sign in with the account that should get the game, then enter the key there.
This is the answer to "how to activate a Steam key on the website": it is Steam's own page, and you don't need the client installed to use it.
On mobile
Steam Support lists two routes today: the Steam client and the browser page. It gives no menu path for the Steam mobile app, so we don't describe one. The browser page is an ordinary web page, so the route Steam documents for a phone is the same one: open the register-key address in your phone's browser and sign in.
Before you press confirm
Check which account is signed in. Steam's Subscriber Agreement says the original activation key can't be registered to any other account afterwards, so a key activated on the wrong account stays there.
What a registered key means
Steam Support says that after a key is registered to your Steam account, it acts as proof of purchase for the game. It also says a key can only be tied to one account: try to register it a second time and you get a duplicate product code error. Keep the key in your order history even after it has worked.
Invalid or duplicate key: what Steam says
Steam's "Retail CD Keys" page names two errors.
| Message | What Steam says it means | What to do |
|---|---|---|
| Invalid Product Code | Steam does not recognise the key. It may not be meant for Steam, or a character is wrong | Check the product is a Steam key, then copy the key again |
| Duplicate product code | The key is already tied to a Steam account and can't be registered again | Check your own library first, then contact the seller |
Characters Steam asks you to check
For an invalid code, Steam lists these mix-ups: the number 0 against the letters O, Q or D; the number 1 against the letters I or L; the letter B against the number 8; the letter G against the number 6. Copying the key from your order page avoids all of them.
When the seller has to step in
Steam Support states that it cannot issue replacement keys for keys bought outside Steam, and sends you back to the seller. For a key bought on KryptoMate, that is our support team. The checks and the details to send are in Game key not working.
Before you buy a Steam key from us
- Platform. The details list on the product page has a Platform line. It must say Steam. A key for another launcher shows as invalid on Steam.
- Region. Read the Region line and the Can be activated in line. See how to check a key's region lock.
- Form. A product whose name says "Gift" or "Account" is not a key and is not entered in this window. Steam key vs Steam gift vs account explains the difference.
- Activation details. When a product has its own steps, the page shows an Activation details tab.
These are Steam products in our games catalogue today:
| Product | Region | Price |
|---|---|---|
| WARDOGS PC Steam CD Key | Other | $34.64 |
| Football Manager 26 EU PC Steam CD Key | Europe | $16.36 |
| Europa Universalis V PC Steam CD Key | Rest Of The World | $45.51 |
| NIGHTREIGN (EU Steam) Mystery Steam CD Key | Europe | $7.26 |
| The Elder Scrolls IV: Oblivion Remastered PC Steam CD Key | Rest Of The World (row) - Custom | $32.51 |
| Clair Obscur: Expedition 33 Deluxe Edition PC Steam CD Key | Rest Of The World | $34.79 |
| Origins RoW (Steam) Mystery Steam CD Key | Rest Of The World | $6.05 |
| Warhammer 40,000: Space Marine 2 PC Steam CD Key | Region Free | $15.09 |
From the KryptoMate catalogue on 11 Oct 2026. A few popular Steam products. Prices and stock change; each product's page shows today's price and its "Region" line.
Delivery is usually instant, but it might take 0–24 hours in rare cases. An invalid or undelivered key is reviewed under the Refund Policy when you report it within 48 hours of delivery. A key you have already activated is final.
Bought the key with crypto?
Nothing changes on Steam's side: a key paid for with USDT or Bitcoin is activated exactly like any other. Keys are under Games, and How to pay On-Chain explains the payment step.
Frequently asked questions
Open the Steam client and log in. Click the Games menu, choose Activate a Product on Steam..., and follow the on-screen instructions. Steam Support also links a browser page for registering a key.
Ready? Check the Platform and Region lines, then pick your key under Games.
Get startedLast checked: 11 Oct 2026. Prices, products and payment options change; the checkout shows what applies to your order.