If you are entering a code for a currency different than your local currency, Steam will convert it to your currency using the day’s exchange rate. You’ll be informed of the conversion before it takes place. [1] X Research source
If you don’t have a Steam account, you can follow the prompts on the login screen to create one for free.
If you are entering a code from another region, the total will be converted to your local currency using the day’s exchange rate.
You may be informed that your code will be converted into your local currency. Steam uses the daily conversion rate when converting currency.
The funds should appear immediately, but the process may take up to two hours.