Ever Miscaluclate XP??

[Mystery Man]

ROFL!!!

Don't laugh. I did that too.

It was the Pharoah module. Oh well, young and dumb....

 

[dcas]

Don't laugh. I did that too.

It was the Pharoah module. Oh well, young and dumb....

Of course. It was easy to do.

If you're concerned that you aren't prepared for the characters to have attained such a level, you could have them go up against some spectres or vampires. At least one of them is certain to lose a couple of levels!

 

[Arnwyn]

Does this seem fair?

Sure it seems fair. It would also be fair to let them keep everything, as it would be fair to yank all the extra XP and level.

In other words, do what is right for you, your group, and your campaign. If their new level doesn't harm anything, then great. However, if them getting a new level throws a whole lot of work back on you, then you're perfectly within your rights to correct the PCs XP and level.

As to this thread's title question: yes, I've miscalculated XP a couple times (not often, as I am an accountant...). If it isn't much I just leave it, but if it's a whole lot I make the appropriate correction. The players understand how much work it is to be a DM (why they refuse to - the classic "3e is the game that everyone wants to play and no one wants to DM"), so they know that sometimes an overworked DM can make a mistake.

 

[Painfully]

It's a DM's privilege to give out more or less XP. Give your players what you think they've earned for the session, and that's that. If you need a calculator to make you feel like a fair DM, that's okay. But, I've often found that what I planned to be a tough encounter turns out to be easy, or the opposite happens, and an easy encounter turns out to be tough.

Keep things easy for yourself. DM'ing is as easy as you make it.