This 15-Minute Task Could Boost Your Paycheck by $200 a Month

December's tax cut means millions of Americans will owe less money when they file their 2018 tax returns. Indeed, the new law is expected to give a typical middle earner a tax cut of nearly $1,000 for 2018, according to the Tax Policy Center.

But the due date for those 2018 returns, in April 2019, is pretty far off -- and until now, there was no good way for you to predict exactly what you will owe, and whether too much or too little is being diverted from your regular paycheck to cover that.