You don't have a choice about how to do it in many cases, though I think I know the example you mean which is valid. One example of how preliminary numbers (a

You don't have a choice about how to do it in many cases, though I think I know the example you mean which is valid. One example of how preliminary numbers (a better phrase than intermediate) aren't rounded would be if someone has three Forms W-2 in a year, such as from three jobs. All three Box 1 amounts are added up unrounded regardless of whether you put a whole dollar wage total on Form 1040. If the three Box 1 amounts end in 35 cents, 40 cents, and 45 cents (just to pick a suitable example), you're going to show an extra buck of wage income than if you could round those cents away. IRS guidance from the 1040 instructions: "You can round off cents to whole dollars on your return and schedules. If you do round to whole dollars, you must round all amounts. To round, drop amounts under 50 cents and increase amounts from 50 to 99 cents to the next dollar. For example, $1.39 becomes $1 and $2.50 becomes $3. If you have to add two or more amounts to figure the amount to enter on a line, include cents when adding the amounts and round off only the total."