Example of a progressive, simplified income tax form:

IRS FORM A
Name: ______________________________________________
Social Security Number: ___-__-____ OR
State ID Number: ____________

1. Total individual income from all sources:
Records available to the IRS show your income
to be at least $XXXXXXX. _________________
2. If line 1 is less than $33,000, enter again here.
If line 1 is $33,000 or more, enter $33,000 here:
Records available to the IRS show this amount
to be at least $XXXXXXX. _________________
3. If line 1 is less than $66,000 but $33,000 or more,
subtract $33,000 and enter the difference here.
If line 1 is $66,000 or more, enter $33,000 here:
Records available to the IRS show this amount
to be at least $XXXXXXX. _________________
4. If line 1 is less than $100,000 but $66,000 or more,
subtract $66,000 and enter the difference here.
If line 1 is $100,000 or more, enter $34,000 here:
Records available to the IRS show this amount
to be at least $XXXXXXX. _________________
5. If line 1 is less than $500,000 but $100,000 or more,
subtract $100,000 and enter the difference here.
If line 1 is $500,000 or more, enter $400,000 here:
Records available to the IRS show this amount
to be at least $XXXXXXX. _________________
6. If line 1 is $500,000 or more, subtract $500,000
and enter the difference here:
Records available to the IRS show this amount
to be at least $XXXXXXX. _________________
7. Sum the following: 10% of line 2, 20% of line 3,
25% of line 4, 30% of line 5, and 40% of line 6.
THIS IS YOUR TOTAL INCOME TAX. Enter it here:
Records available to the IRS show this amount
to be at least $XXXXXXX. _________________
8. Calculate 10% of line 1. THIS IS YOUR TOTAL SOCIAL
SECURITY TAX. Enter it here:
Records available to the IRS show this amount
to be at least $XXXXXXX. _________________
9. Add lines 7 and 8 here:
Records available to the IRS show this amount
to be at least $XXXXXXX. __________________
Records available to the IRS show your total tax withholding
to be $XXXXXXX.
If this is greater than or equal to line 9, you may submit this form
for a tax refund.
If this is less than line 9, submit this form along with the attached
payment form below (IRS FORM P).
Submit this form and any necessary payments by April 15. Forms received
after April 15 are ineligible for any tax refund.
If additional payment is due to the IRS but not received by April 15,
penalties will be added to your tax liability, as described on
IRS FORM X. FAILURE TO PAY INCOME TAXES IS A FEDERAL CRIMINAL OFFENSE
PUNISHABLE BY UP TO 5 YEARS IN PRISON.
"Total individual income" includes wages, salaries, tips, revenue from
sale of capital assets, stock dividends, and inheritance of cash assets.
It does not include acquisition of non-cash assets including real or
personal property, securities, or other capital assets. However, any
sale or liquidation of non-cash assets may then become subject to
income tax. In general, one-time transactions of less than $1,000
may be omitted. Detailed rules are available in IRS DOCUMENT I,
available at http://www.irs.gov/documents/i/ or at your local library
or post office.
For any recurring transactions, or one-time transactions of $1,000
or above, IRS Form R or O should have already been submitted to the
IRS. We have enclosed copies of those forms in this mailing. If any
of these forms are in error, file a copy of IRS FORM C to appeal
for a correction.

About one page, and in the best case you just copy down the numbers the IRS already gave you and mail it in after 5 minutes of thought. Note that the exact rate structure is an arbitrary guess on my part, but is even more progressive than the current system.