WASHINGTON — The deadline is upon us, and people across the country are finishing up an estimated 3.18 billion hours figuring out and filing their tax returns.

That's 24.2 hours per taxpayer.

If it's any consolation, most people get a two-day reprieve this year, until midnight tonight. April 15 fell on a Sunday and April 16 is Emancipation Day, a legal holiday in the District of Columbia.

Some people need all the time they can get to cope with a system that every year, with changes in tax law, becomes more complicated.

The National Taxpayers Union, an advocacy group, came up with its estimate of 3.18 billion hours for individual compliance based on an IRS report on forms submitted. The group did not have an estimate for past years, but the Tax Foundation, using similar means of calculation, said the figure for the previous year was 2.8 billion hours.

The figures are much higher if you count businesses such as General Electric Co., which may have set a record last year by filing a return that, had it been printed on paper, would have totaled more than 24,000 pages.

The NTU calculated that the average taxpayer spent 24.2 hours in record-keeping, boning up on tax law and preparing the 2006 return. With some 60 percent of people now using paid preparers, the group said the average cost of paying taxes is $207.

Corporations spent an estimated $156.5 billion working on their taxes, nearly half the $354 billion in corporate income taxes the U.S. collected last year, NTU said.

"This spring you have people spending more on tax preparation than our government is spending on higher education," said Sen. Ron Wyden, D-Ore., who is sponsoring a tax simplification bill with a one-page 1040 form for most taxpayers. "It shouldn't have to be bureaucratic water torture to fill out all these forms."

Despite the obstacles, most Americans make an honest effort to pay their taxes on time. Internal Revenue Service Commissioner Mark Everson said the agency expects to process 136 million returns this year. As of April 7, they had received 88.1 million. For most, the effort is rewarded: As of April 7, the IRS had issued 73.6 million refunds totaling $174 billion. The average refund was $2,366.

So far, the IRS said, 61 million returns had been filed electronically, up 6.2 percent from last year. Of those, 44 million came from tax professionals and 17 million from people using software on their home computers. The agency said its Web site — www.irs.gov/ — had received 111 million visits from people seeking help or information.

Things are tough for the IRS as well. Everson told a Senate committee last week that the agency was anticipating "the most difficult filing season in a number of years."

Congress late last year complicated matters when it failed to revive — until after the IRS had gone to print with its forms for the 2006 filing season — expired tax breaks for college tuition, teacher expenses and state taxes.

The IRS has also had difficulty making taxpayers aware that they are entitled to a one-time tax refund, worth $30 to $60 in most cases, for a long-distance phone tax that was eliminated last year. Almost one-third of returns coming in so far have not sought the rebate, and there have been scattered problems with taxpayers and unscrupulous preparers claiming refunds of thousands of dollars.

The IRS also is under pressure from Congress, hungry for new revenue sources, to narrow the tax gap, the difference between taxes owed and taxes paid. The IRS estimates that amount at $290 billion a year.

About 84 percent of taxpayers voluntarily comply with the law on what they owe. Raising that by just one percentage point "will yield an additional $25 billion each year to pay for priorities like children's healthcare and energy independence," said Senate Finance Committee Chairman Max Baucus, D-Mont.

Everson said enforcement revenue was up from $34 billion in fiscal 2002 to almost $49 billion last year.

Most taxpayers had a less than 1 percent chance of getting audited last year, but the rate rises to 6.3 percent for millionaires and 35.3 percent for the largest corporations.

For those who find this all too daunting, the IRS does accept extensions from 30 to 120 days, depending on circumstances. The tax agency urges those seeking extensions to set up an installment agreement, for a fee of up to $105, that will result in lower penalties and interest.

Where to drop off returns in Hawai'i

The U.S. Postal Service said it will have late pickups tonight at locations around the state. (The deadline for state income tax returns is April 20.) People using this service should deposit their mail in specially marked collection boxes at the following locations: