Solo mining calculations?

Hello everyone, I was curious as to if anyone knew a way to somewhat accurately calculate my odds of mining a block solo mining? I know that it's generally not recommended and usually brings less profit than pool mining but I just want to see what my odds would be out of curiosity, I know that places like 2cryptocalc exist but I want to be able to do it on my own without an online calculator like that. Thank you to anyone who has useful information!