Tax season is kicking into high gear, with some 40 million Americans now having filed their tax returns — roughly a quarter of expected filings. It's also when the IRS starts processing refunds claiming the Earned Income Tax Credit, which it's legally required to hold until mid-February.

If you're among those who have already filed, you might be wondering: when will I get my refund?

How long do you need to wait?

Depending on how you file your tax return and how you choose to receive your refund, you can expect to wait anywhere from two weeks to several months. Here are the typical waiting times, according to Ray Martin, a longtime financial advice columnist for CBS MoneyWatch.

Six weeks or more — if you file by paper and request a paper check.

Four weeks or more — if you file electronically and request a refund by paper check.

About 10 business days — if you e-file and elect direct deposit.

The IRS says that 90% of refunds are processed within 21 days. Legally, though, the government could wait much longer.

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"The IRS can pay a refund up to 45 days after April 15 without owing interest," said Janet Holtzblatt, a senior fellow at the Urban-Brookings Tax Policy Center who previously worked at the Treasury and the Congressional Budget Office.

Filing electronically is faster

One way to ensure you get your refund promptly is to file your taxes electronically. E-filing reduces processing time in several ways. If you file on paper, someone needs to enter that information into an electronic system to process your return. E-filing removes that step, which cuts down on processing time and reduces the likelihood that errors will be introduced in the scanning process.

When you're ready to file, you'll want to check over your return before you hit "send," since even small errors can create delays in your refund.

"There can be delays for a whole host of different reasons. If there's some kind of mistake on your form, if your Social Security number isn't correct or your address doesn't match," Kimberly Palmer, a personal finance expert with NerdWallet, told CBS MoneyWatch.

That means verifying if you've had bigger changes, such as changing jobs, moving, getting married or having a child.

If you're claiming the EITC or ACTC

For the 25 million taxpayers who claimed the Earned Income Tax Credit or the 20 million claiming the Additional Child Tax Credit, refunds will start getting processed the week of February 17. That's because the government is legally required to wait until mid-February to process those refunds as part of an effort to crack down on tax fraud.

Once the processing starts, it takes another few weeks for the money to be paid. If you filed electronically and chose to direct-deposit your refund, the money should reach your bank account by the first week of March, the IRS says.

Checking your refund status

If you file electronically, you can check your refund status on the IRS' website starting 24 hours after you file. If you file on paper, you'll be able to check your refund status after four weeks.

The agency recommends you check your refund status online, if possible, rather than calling. If you do pick up the phone, bear in mind that the week following Presidents Day is typically the IRS' busiest.