If I incur an expense for a service on the last day of the month, can I accrue that expense in that month by estimating the amount the final bill will be? Assume I will receive an invoice later that will be very close to my estimate.

Assuming I receive the invoice before I finish closing out the month, can I still include it in the month's expenses? How many days past the end of the month is it acceptable to post expenses. It usually takes about a week to finish.

Or do I need to have an actual copy of the invoice in order to record the expense?

Thanks!

Yes accruals should be recorded at year end for the services provided during the year. For example waterm elictricity and telephone bills can be estimated and recorded even if you still did not receive any invoice. And when you receive the actual invoice you can adjust the difference.