08-28-2018, 06:55 AM

Up to 85% of Social Security benefits may be taxed. The exact amount that is subject to tax is determined via a somewhat confusing calculation with non-intuitive results. In addition, once you know how much is taxed, the marginal impact from that income may be much higher than one might expect, e.g., if it pushes, say, other income (e.g., investment income) into a higher tax bracket. So, knowing the amount subject to tax may really be just one important input.

There's a good free on-line calculator to estimate the amount subject to tax: How much of my social security benefit may be taxed?

In my own case, I try to have a spreadsheet to estimate my taxes for the year. Part of that spreadsheet has a "subroutine" to estimate the amount of social security that night be subject to tax. As others might have an interest in that kind of calculation, I attach the excel spreadsheet "subroutine" here. The input cells are in yellow and the other cells are protected (although you can turn that off; there is no password).

If anyone finds a significant difference between my spreadsheet and the link above, please let me know so I can correct it.

There's a good free on-line calculator to estimate the amount subject to tax: How much of my social security benefit may be taxed?

In my own case, I try to have a spreadsheet to estimate my taxes for the year. Part of that spreadsheet has a "subroutine" to estimate the amount of social security that night be subject to tax. As others might have an interest in that kind of calculation, I attach the excel spreadsheet "subroutine" here. The input cells are in yellow and the other cells are protected (although you can turn that off; there is no password).

If anyone finds a significant difference between my spreadsheet and the link above, please let me know so I can correct it.