Chapter 27: Putting It Together
The worksheets from Chapter 27 of Fifty-Five. Type your own numbers, or try an example from the book to see how each one works.
The Social Security difference
What a claiming age does to each monthly benefit, to a couple's yearly Social Security, and to the check the survivor keeps. Run it once for each plan you are comparing.
The formula: Benefit at full retirement age × Claiming adjustment = Monthly benefit. Add both spouses, × 12 = Yearly Social Security.
The calculator needs JavaScript. The paper worksheet below does not: it is the same arithmetic, written out.
The paper worksheet
Your benefit at full retirement age $__________ × Adjustment ______ = Your monthly benefit $__________
Spouse's benefit at full retirement age $__________ × Adjustment ______ = Spouse's monthly benefit $__________
Total monthly $__________ × 12 = Yearly Social Security $__________
Walk through it, step by step
- Get both benefits at full retirement age from your Social Security statements (Chapter 1).
- Pick a claiming age for each of you.
- Find each adjustment: 0.70 at 62, 0.8667 at 65, 1.00 at 67, 1.24 at 70, for anyone with a full retirement age of 67.
- Multiply, add, and multiply by 12.
Check your answer
- Waiting from 65 to 70 should raise a benefit by about 43%: 1.24 ÷ 0.8667 = 1.43.
- The survivor's check should equal the larger of the two checks, not the total.
Figures this worksheet uses, and where they come from: Claiming early cuts the benefit by 5/9 of 1% a month for the first 36 months: 0.8667 at 65 and 0.70 at 62, with a full retirement age of 67 (SSA, Starting Your Retirement Benefits Early); Delayed retirement credits: 1.24 at 70, with a full retirement age of 67 (SSA, Delayed Retirement Credits); The survivor keeps the larger of the two checks (SSA, Survivors Benefits).
What the conversions cost
The extra federal income tax a Roth conversion adds in one year. It works the tax once without the conversion and once with it, using the 2026 brackets for a joint return.
The formula: Other income + Conversion − Deduction = Taxable income. Find the tax using the brackets. Do it once without the conversion and once with it. The difference is what the conversion costs.
The calculator needs JavaScript. The paper worksheet below does not: it is the same arithmetic, written out.
The paper worksheet
Without the conversion: Other income $__________ − Deduction $__________ = Taxable income $__________. Tax on that amount: $__________
With the conversion: Other income $__________ + Conversion $__________ − Deduction $__________ = Taxable income $__________. Tax on that amount: $__________
Tax with $__________ − Tax without $__________ = Cost of the conversion $__________
Walk through it, step by step
- Write your other income for the year: wages, pensions, interest, dividends and any other withdrawals.
- Subtract your deduction: $32,200 for a joint return in 2026 if you're both under 65, or the amount your tax preparer gives you. That's your taxable income without the conversion.
- Figure the tax: 10% of the first $24,800, plus 12% of anything above $24,800 up to $100,800, plus 22% of anything above that.
- Now add the conversion you're thinking about to your other income, and do steps 2 and 3 again.
- Subtract the first tax from the second. The difference is what the conversion costs.
Check your answer
- If the conversion stays inside one bracket, its cost is the conversion times that rate. For Carol: $25,000 × 0.12 = $3,000. It matches.
- If you buy health coverage through the Marketplace before 65, a conversion also raises the income used for your premium tax credit. Add that cost (Chapter 5).
- From 63 on, check the total against the IRMAA lines too (Chapter 11).
Figures this worksheet uses, and where they come from: 2026 brackets for a joint return: 10% on the first $24,800 of taxable income, 12% from there to $100,800, 22% from there to $211,400 (IRS, tax inflation adjustments for tax year 2026, IR-2025-103); 2026 standard deduction for a joint return, both under 65: $32,200 (IRS, tax inflation adjustments for tax year 2026, IR-2025-103).
Your MAGI at 75
A rough MAGI for the year your required withdrawals begin: your first RMD, less any QCDs, plus other income, plus the taxable part of your Social Security.
The formula: Pre-tax balance going into the year ÷ 24.6 = First RMD. First RMD − QCDs + Other income = Income before Social Security. Then add your taxable Social Security = MAGI.
The calculator needs JavaScript. The paper worksheet below does not: it is the same arithmetic, written out.
The paper worksheet
Pre-tax balance going into the year $__________ ÷ 24.6 = First RMD $__________
First RMD $__________ − QCDs $__________ + Other income $__________ = Income before Social Security $__________
Income before Social Security $__________ + Taxable Social Security $__________ = MAGI $__________
If your RMDs start at 73, divide by 26.5 instead of 24.6.
Walk through it, step by step
- Rough in your pre-tax balance going into the year you turn 75 with the growth multiplier in Chapter 3, or use the projection from Chapter 7 if you're converting. Subtract what you expect to withdraw along the way.
- Divide by 24.6 (or 26.5 if your RMDs start at 73).
- Subtract any QCDs you plan to make.
- Add your other income: pensions, interest, dividends.
- Work out your taxable Social Security with the worksheet in Chapter 24.
- Add the results of steps 4 and 5 to what's left of your RMD after step 3. That's your MAGI at 75.
Check your answer
- Compare your MAGI with $218,000 (joint) and $109,000 (single).
- Then do it again for the survivor, filing single, with only the larger Social Security check. That's usually where the line bites.
Figures this worksheet uses, and where they come from: Uniform Lifetime Table factors: 24.6 at age 75 and 26.5 at age 73 (IRS, Internal Revenue Bulletin 2024-33, T.D. 10001); Taxable Social Security: joint lines of $32,000 and $44,000, single lines of $25,000 and $34,000, the 50% and 85% rules, and the $6,000 and $4,500 amounts that are half the gap between the lines (IRS, Publication 915); IRMAA income lines of $218,000 (joint) and $109,000 (single) (SSA, Premiums: Rules for Higher-Income Beneficiaries).