adwords daily budget exceeded

Can anyone tell me why if I set up daily budget to $50, sometimes the figure goes over that and my daily spent is $55 or $58.

Is there any way to stop that from happening?

 

The daily budget is figured as an average of the monthly budget - If your daily budget is $10, some days you may have spends of $12, but at the end of a 30 day month, your budget will not exceed $300 ($10/day * 30 days). If your budget does go over at the end of the month, Google will still only charge you the $300, and the rest is considered free clicks (overdelivery in Google's terms).

 

thanks mate. that was the answer i was looking for

 

For your reference here's the official answer:

Why am I being charged for more than my daily budget on some days?