Q: I’m used to April 15 being tax day. Why the change this year?

A: Emancipation Day will be observed April 15 in Washington, D.C., and by law, the tax filing deadline for the nation is moved to the next business day, Monday, April 18.

Q: What are the most common errors made by tax filers?

A: Now that most returns are prepared on computers and e-filed to the IRS, the most common errors are data input mistakes. Take your time, make sure your information is entered correctly, and chances are the tax software will give you an error-free tax return.

Q: Do I have to buy a tax software program to file online?

A: IRS Free File at IRS.gov allows filers whose household income was $58,000 or less last year to use brand-name tax software at no cost. E-filing is fast, easy and secure. It provides a virtually error-free return and a fast refund.

Q: I’ve procrastinated too much and really won’t be able to get all of my paperwork together to finish filing by the deadline. Am I in big trouble?

A: Don’t miss the filing deadline, especially if you owe taxes. File your tax return or ask for an extension by April 18. An extension gives you until Oct. 17, 2011, to file your return but does not extend your time to pay taxes due. No reason is required to get an extension and IRS Form 4868 should be accepted with or without payment as long as it is correctly completed and filed by April 18. You can file for an extension at no cost through IRS Free File at IRS.gov.

Q: How much could the penalty be if I file late?

A: If you owe $1,000, the penalty for filing a return late could be as much as $250. By paying as much as you can when you file, the amount of interest and late payment penalty owed will be less.