You can also pay using EFTPS, a free tax payment system that allows you to make payments online or by phone. For more information or details on enrolling, visit www.irs.gov/e-pay or www.eftps.gov or call EFTPS' Customer Service at 1-800-316-6541. TTY/TDD help is available by calling 1-800-733-4829.

Include any estimated tax penalty from line 77 in the amount you enter on line 76.

You can pay by check, money order, or credit or debit card. Do not include any estimated tax payment for 2011 in this payment. Instead, make the estimated tax payment separately.

Make your check or money order payable to the United States Treasury for the full amount due. Do not send cash. Do not attach the payment to your return. Write 2010 Form 1040 and your name, address, daytime phone number, and social security number (SSN) on your payment. If you are filing a joint return, enter the SSN shown first on your tax return.

To help process your payment, enter the amount on the right side of the check like this: $ XXX.XX. Do not use dashes or lines (for example, do not enter $ XXX– or  
$ XXXxx/100).

Then, complete Form 1040-V following the instructions on that form and enclose it in the envelope with your tax return and payment. Although you do not have to use Form 1040-V, doing so allows us to process your payment more accurately and efficiently.

For information on paying your taxes with a credit or debit card, go to www.irs.gov/e-pay.

If you cannot pay the full amount shown on line 76 when you file, you can ask for:

• An installment agreement, or
• An extension of time to pay.

Under an installment agreement, you can pay all or part of the tax you owe in monthly installments. Generally, you can have up to 60 months to pay. However, even if your request to pay in installments is granted, you will be charged interest and may be charged a late payment penalty on the tax not paid by April 18, 2011. You must also pay a fee. To limit the interest and penalty charges, pay as much of the tax as possible when you file. But before requesting an installment agreement, you should consider other less costly alternatives, such as a bank loan or credit card payment.

To ask for an installment agreement, you can apply online or use Form 9465. To apply online, go to IRS.gov, click on I Need To and select Set Up a Payment Agreement. If you use Form 9465, you should receive a response to your request to make installment payments within 30 days. But if you file your return after March 31, it may take us longer to reply.

If paying the tax when it is due would cause you an undue hardship, you can ask for an extension of time to pay by filing Form 1127 by April 18, 2011. An extension generally will not be granted for more than 6 months. If you pay after April 18, 2011, you will be charged interest on the tax not paid by April 15, 2011. You must pay the tax before the extension runs out. If you do not, penalties may be imposed.

You may owe this penalty if:

• Line 76 is at least $1,000 and it is more than 10% of the tax shown on your return, or
• You did not pay enough estimated tax by any of the due dates. This is true even if you are due a refund.

For most people, the tax shown on your return is the amount on your 2010 Form 1040, line 60, minus the total of any amounts shown on lines 63, 64a, 65, 66, 67, and 70 and Forms 8828, 4137, 5329 (Parts III through VIII only), 8801 (line 27 only), 8839, 8885, and 8919. Also subtract from line 60 any tax on an excess parachute payment, any excise tax on insider stock compensation of an expatriated corporation, any uncollected social security and Medicare or RRTA tax on tips or group-term life insurance, any look-back interest due under section 167(g) or 460(b), and any write-in tax included on line 60 from Form 8885. When figuring the amount on line 60, include household employment taxes only if line 61 is more than zero or you would owe the penalty even if you did not include those taxes. But if you entered an amount on Schedule H, line 7, include the total of that amount plus the household employment taxes on Form 1040, line 59.

You will not owe the penalty if your 2009 tax return was for a tax year of 12 full months and either of the following applies.

1. You had no tax shown on your 2009 return and you were a U.S. citizen or resident for all of 2009.
2. The total of lines 61, 62, and 69 on your 2010 return is at least 100% of the tax shown on your 2009 return (110% of that amount if you are not a farmer or fisherman, and your adjusted gross income (AGI) shown on your 2009 return was more than $150,000 (more than $75,000 if married filing separately for 2010)). Your estimated tax payments for 2010 must have been made on time and for the required amount.

For most people, the tax shown on your 2009 return is the amount on your 2009 Form 1040, line 60, minus the total of any amounts shown on lines 63, 64a, 65, 66, and 67 and Forms 8828, 4137, 4136, 5329 (Parts III through VIII only), 8801 (line 29 only), 8885, and 8919. Also subtract from line 60 any tax on an excess parachute payment, any excise tax on insider stock compensation of an expatriated corporation, any uncollected social security and Medicare or RRTA tax on tips or group-term life insurance, any look-back interest due under section 167(g) or 460(b), and any write-in tax included on line 60 from Form 8885. When figuring the amount on line 60, include household employment taxes only if line 61 is more than zero or you would have owed the estimated tax penalty for 2009 even if you did not include those taxes. But if you entered an amount on your 2009 Schedule H, line 7, include the total of that amount plus the household employment taxes on your 2009 Form 1040, line 59.

If the Exception on page 71 does not apply and you choose to figure the penalty yourself, see Form 2210 (or 2210-F for farmers and fishermen) to find out if you owe the penalty. If you do, you can use the form to figure the amount.

Enter any penalty on line 77. Add the penalty to any tax due and enter the total on line 76.

However, if you have an overpayment on line 73, subtract the penalty from the amount you would otherwise enter on line 74a or line 75. Lines 74a, 75, and 77 must equal line 73.

If the penalty is more than the overpayment on line 73, enter -0- on lines 74a and 75. Then subtract line 73 from line 77 and enter the result on line 76.

Do not file Form 2210 with your return unless Form 2210 indicates that you must do so. Instead, keep it for your records.