[brezelgoring]

If you're only concerned about metrics on some bossware, overestimating seems acceptable if you lack the experience to accurately fashion a real timetable, and with time, you'll do it better and better.

If you're working with humans you can overshoot, which will make you look great if you take less time than estimated, or just say you'll give an estimate once you've started the task, they should understand (Consider using: "How long? Let me look into it first", "How long? About $(your_bad_estimate)*1.5 minutes" or similar). And if they don't understand, consider asking why that estimate is so important in the first place.

Maybe the customer must approve jobs before they are executed, and the customers get an estimate billing based on your estimated time? A big estimate might scare them. Who knows?