I found an old BTC wallet. The password should have about 8 characters but forgot it unfortunately. Is there a realistic chance to recover it or is this hopeless?
This depends on the char set you used for your password. The numbers below are from Wikipedia (no guarantee) and describe how long it takes to crack a password with a standard PC + GPU. They are for the case that the password exactly 8 characters.
[0-9]: 100 ms
[a-z]: 4 min
[A–Z; a–z; 0–9]: 3 days
[A–Z; a–z; 0–9] + Special Characters: 84 days
So in the case of 8 characters there is a certain chance that you can crack it. However, if you only used a 9 characters pw, the last two cases already way more difficult.
[A–Z; a–z; 0–9]: 159 days
[A–Z; a–z; 0–9] + Special Characters: 22 years.
So for passwords with special characters 8 is the maximum length you have a chance. If the password only contains [0-9] or [a-z] there is a chance until 11-12 chars.