Steam's refund policy is the one most players know by heart, and it is genuinely generous when you meet it: a game is refundable if you request within 14 days of purchase and have played it for less than 2 hours. Online, offline, and Steam Family shared playtime all count toward that 2-hour cap. The exact wording lives on the Steam refund policy page.
The clock and the counter are independent. You can be at 13 days with 1 hour played (eligible) or 3 days with 3 hours played (not eligible) — both conditions must hold. Pre-orders are refundable any time before release; after release the standard 14-day / 2-hour window applies. Most eligible requests are approved within a few hours to a few days and paid to your Steam Wallet or original payment method.
There are real exceptions worth knowing. Video content (movies, documentaries), third-party CD keys bought outside Steam, physical gift cards, and games with an active VAC ban are not refundable. DLC is refundable within 14 days if the base game has under 2 hours played since the DLC purchase and the DLC isn't consumed; Valve in-game purchases are refundable within 48 hours if not consumed. See the policy page for the full list.
Before you submit, run the eligibility checker to confirm your dates and playtime against the rule. If you're outside the window or over the playtime cap, jump to the disputes guide for the next steps rather than a standard refund.