Looking for ways to cut your tax bill? Here’s an easy one: Just file your federal tax return by April 15.

Really. That’s it. If you expect to owe money to the IRS, and you either don’t want to or just can’t afford to write that check by the deadline, file your 1040 anyway. Or at least file for an automatic six-month extension.

Otherwise, you will end up paying a failure-to-file penalty worth up to 25% of what you owe in the first place. And that’s before counting the failure-to-pay penalty and interest. Both penalties would kick in on April 16.

For the first year, the biggest hit to your wallet will be that failure-to-file penalty, which amounts to 5% of the tax owed every month — or part of a month — for five months, capping out at 25%.

The failure-to-file penalty is also capped at 25% of the tax you owe, but it accrues more slowly — at 0.5% a month for 50 months.

But when both penalties apply in the same month, the combined maximum will be 5%, instead of 5.5%.

Say you owe an additional $5,000 on your 2014 tax return. But you don’t get around to filing that return until Jan. 1, 2016 — eight-and-a-half months after the deadline.

You’ll ring in the New Year owing an additional $1,125 in failure-to-file penalties alone.

On top of that, you would owe $225 for failure-to-pay penalties, plus $133 in interest.

Your grand total: $6,483 or 30% more than you owed in the first place.

If you do apply for a 6-month extension, you will avoid the failure-to-file penalty for those six months. And you might also avoid the late payment penalty if you have already paid 90% of the taxes you owed for the year by April 15. You will, however, still owe interest on your remaining tax debt until it’s paid off.

The only way to steer clear of that is to actually pay what you owe by April 15.

Of course, like a lot of Americans, you may not expect to owe any more money on April 15 or may even be due a refund. Filing may be a pain, but do it anyway. Or at least file for an extension.

Why? First, let’s say your assumption that you won’t owe anything is wrong and it turns out you do owe money. If you don’t file, you’ll get hit with all of the above penalties plus interest.

Second, even if you’re right and you’re owed a refund, if you wait too long to file, you may lose it.

You have 3 years to claim that refund. So you have to file your 2014 income tax return by April 15, 2018 or else you will be ‘time barred’ from claiming your refund.