» more from CNBC Explains

Tax breaks and mistakes that can cost you big-time

Most Americans would get an F when it comes to income-tax basics, according to a new NerdWallet.com survey of 1,015 adults. The average respondent scored a mere 50 out of 100 on questions about the tax implications of Roth IRAs, volunteering expenses that are deductible and what the worst tax mistake is. (Answer? Not filing a return at all.)

From start to finish, the average taxpayer filing a Form 1040 spends 16 hours on his or her taxes—including eight hours combing through records. Yet despite that scrutiny, you could still be leaving money on the table. Common errors and overlooked deductions can add up quickly when filing your tax returns. Here are 10 tips to keep more money in your bank account.

—By CNBC's Kelli B. Grant
Posted 25 March 2015

Yenwen Lu | Getty Images