The IRS says people who file with pen and paper are 20 times more likely to make mistakes than those who e-file.
While tax software will crunch the numbers on your tax return for you, filing on your own will require some addition and subtraction -- so make sure to double-check your figures before submitting your return.
If you file by paper, it could take a while for the IRS to process the return and identify the mistakes before it sends it back to you. If you file electronically, however, your return will be rejected immediately if there is any incorrect math, and you will need to resubmit it.
