Chapter 3: Drawing the First Income Map
The worksheets from Chapter 3 of Fifty-Five. Type your own numbers, or try an example from the book to see how each one works.
One year's MAGI and your distance from the line
Your estimated MAGI for one year of your income map, and how far that year is from the IRMAA line.
The formula: Add every kind of income that counts = MAGI. IRMAA line − MAGI = Room under the line. (If MAGI is bigger than the line, flip it: MAGI − IRMAA line = Amount over the line.)
The calculator needs JavaScript. The paper worksheet below does not: it is the same arithmetic, written out.
The paper worksheet
Line A. Wages and self-employment income: $__________
Line B. Pension payments: $__________
Line C. Pre-tax withdrawals and RMDs: $__________
Line D. Roth conversions: $__________
Line E. Interest, dividends and capital gains: $__________
Line F. Taxable part of Social Security: $__________
Line G. Tax-exempt interest: $__________
Line H. MAGI: add A through G: $__________
Line I. Your IRMAA line ($109,000 single or $218,000 joint, for 2026): $__________
Line J. Room under the line (I − H), or amount over the line (H − I): $__________
Walk through it, step by step
- Pick one year on your map. Write each kind of income you expect that year on Lines A through G. Leave a line at $0 if you have none of it.
- Add Lines A through G, one line at a time. Start with A. Add B. Add C to that answer. Keep going through G. Write the final total on Line H. That is your MAGI.
- Write your IRMAA line on Line I: $109,000 if you file single, $218,000 if you file jointly.
- Compare H and I. If H is smaller (or the same), subtract H from I. That is your room under the line. If H is bigger, subtract I from H. That is how far over you are.
- Write the answer on Line J, and write "room" or "over" next to it.
- Copy the MAGI from Line H into the Estimated MAGI column of your map for that year. Repeat for each year.
Check your answer
- If you have room: Line H + Line J should equal Line I. For the couple at 63: $78,000 + $140,000 = $218,000. It matches.
- If you are over: Line I + Line J should equal Line H. For Carol's survivor: $109,000 + $13,940 = $122,940. It matches.
- Did you include tax-exempt interest on Line G? It is the line people forget most.
Figures this worksheet uses, and where they come from: 2026 IRMAA income lines: $109,000 on an individual return and $218,000 on a joint return (SSA, Premiums: Rules for Higher-Income Beneficiaries).
What your balance may grow to
A rough size for a future balance, if it grows at a steady rate and nothing is taken out. It is how the "pre-tax balance at 75" row in Carol's table was figured.
The formula: Today's balance × Growth multiplier = Future balance
The calculator needs JavaScript. The paper worksheet below does not: it is the same arithmetic, written out.
The paper worksheet
Today's balance $__________ × Your multiplier ______ = Future balance $__________
Walk through it, step by step
- Write your pre-tax total today on the first blank.
- Count your years: the age you are planning for minus your age today.
- Pick a growth rate. Try 5% for a cautious guess and 7% for a stronger one. Neither is a promise.
- Find the multiplier in the book's table: go down to your number of years, then across to your rate. Write it on the second blank.
- If your number of years isn't in the table, make your own multiplier. On a calculator, type 1.05 (or 1.07). Then press × 1.05 = once for each year after the first. Count carefully as you go.
- Multiply the first blank by the second blank. Round to the nearest thousand.
- Write the answer on the last blank.
Check your answer
- Use the rule of 72. Divide 72 by your growth rate to see about how many years it takes your money to double. At 7%, 72 ÷ 7 is about 10 years. At 5%, 72 ÷ 5 is about 14 years. Carol's 20 years at 7% is about two doublings: $600,000 to $1.2 million to $2.4 million. Her answer, $2.32 million, is close. If your answer is far from your rule-of-72 guess, check the multiplier.
- This method assumes steady growth and no withdrawals. Real markets go up and down, so treat the answer as a rough size, not a forecast.
This worksheet uses only the numbers you type. It has no government figure built in.
How much of your Social Security is taxable
How much of a year's Social Security benefits counts as taxable income. It follows the IRS's own worksheet, one line at a time.
The formula: Half your benefits + your other income decides how much of your benefits gets taxed, up to a limit of 85%.
The calculator needs JavaScript. The paper worksheet below does not: it is the same arithmetic, written out.
The paper worksheet
Line A. Total Social Security benefits for the year (both spouses if you file jointly): $__________
Line B. A × 0.5: $__________
Line C. All other income that counts: Lines A through E of your MAGI worksheet: $__________
Line D. Tax-exempt interest: $__________
Line E. B + C + D: $__________
Line F. E − first limit ($32,000 joint, $25,000 single). Zero or less? Stop: none is taxable. $__________
Line G. The smaller of F or the middle amount ($12,000 joint, $9,000 single): $__________
Line H. G × 0.5: $__________
Line I. The smaller of B or H: $__________
Line J. F − middle amount. Less than zero? Write 0. $__________
Line K. J × 0.85: $__________
Line L. I + K: $__________
Line M. A × 0.85: $__________
Line N. Taxable Social Security: the smaller of L or M: $__________
Walk through it, step by step
- Write your yearly Social Security on Line A. Use your statement's estimate times 12 if you have a monthly number.
- Multiply Line A by 0.5 (or divide by 2). Write it on Line B.
- Add up your other income that counts and write it on Line C. Leave out Social Security and tax-exempt interest here; they have their own lines.
- Write any tax-exempt interest on Line D.
- Add B, C and D. Write the total on Line E.
- Subtract your first limit from Line E. Write it on Line F. If the answer is zero or below, stop. None of your Social Security is taxable, and Line N is $0.
- Compare Line F with your middle amount. Write whichever is smaller on Line G.
- Multiply Line G by 0.5. Write it on Line H.
- Compare Line B with Line H. Write whichever is smaller on Line I.
- Subtract your middle amount from Line F. Write it on Line J. If the answer is below zero, write 0.
- Multiply Line J by 0.85. Write it on Line K.
- Add Line I and Line K. Write it on Line L.
- Multiply Line A by 0.85. Write it on Line M.
- Compare Line L with Line M. Write whichever is smaller on Line N. That is the taxable part of your Social Security.
- Copy Line N into the "Social Security (taxable part)" column on your map.
Check your answer
- Line N can never be bigger than Line M. If it is, you picked the bigger number in Step 14.
- Line N can never be less than $0.
- If Line E was below your first limit, Line N must be $0.
- This worksheet is simplified for people with no adjustments to income. Married people who file separately and lived together use different numbers.
- Your tax software or tax preparer does the official version of this worksheet each spring. This one is for planning.
Figures this worksheet uses, and where they come from: First limits of $32,000 (married filing jointly) and $25,000 (single), and middle amounts of $12,000 and $9,000 (IRS, Publication 915); The 50% and 85% rules, and the limit of 85% of benefits (IRS, Publication 915).