What's customary
10% is the standard tip for a good metered taxi ride. Rounding up to the nearest 100 or 500 HUF is common for short rides where 10% would be only a few hundred forints.
How to tip
Tell the driver the total including tip when you pay — e.g. 'tizezerkettoszaz' (12,200) for an 11,000 HUF fare. Handing over the exact change and saying 'thanks, keep it' also works.
App-based rides
Bolt and Uber both support in-app tipping after the ride (usually 10 / 15 / 20% options). The driver sees it the next day. You can also tip in cash at drop-off.
Pre-booked private transfers
Most include the tip in the quoted price. A few thousand forints (or €5–10) for exceptional service is appreciated but not expected.