Which Form 990 do I file?
Three questions: 990-N, 990-EZ, 990 or 990-PF.

Work out which return you file, when it is due, what a late return costs and where you stand on public support, payout and UBIT. The tools run in your browser; nothing you enter is sent anywhere.
Three questions: 990-N, 990-EZ, 990 or 990-PF.
Original and extended due dates, weekends and holidays included.
The daily penalty and its cap for a late or incomplete return.
Schedule A Part II: do you meet the 33⅓% test?
Minimum investment return, excise tax and what is left to distribute.
When three missed years would revoke your exemption.
Form 990-T tax on unrelated business income.