Retirement Tax Calculator
See your actual tax burden from different retirement income sources — including how much of your Social Security is taxable, bracket room for Roth conversions, and IRMAA Medicare thresholds.
Income Breakdown
Bracket Room Analysis
How Social Security Taxation Works
Unlike most income, Social Security isn't taxed on its face value. The IRS uses a "combined income" formula: AGI + nontaxable interest + ½ × SS benefit. Based on this combined income, 0%, 50%, or 85% of your SS benefit is added to taxable income.
- Single: Combined income under $25,000 → 0% taxable. $25,000–$34,000 → up to 50%. Over $34,000 → up to 85%.
- Married filing jointly: Under $32,000 → 0%. $32,000–$44,000 → up to 50%. Over $44,000 → up to 85%.
Important: "up to 85%" doesn't mean 85% of SS is taxed at 85%. It means a maximum of 85% of your SS benefit is included in your taxable income — then normal income tax rates apply to that portion.
2026 Deductions for Retirees
For 2026 the standard deduction is $16,100 (single) or $32,200 (married filing jointly). Each filer who is 65 or older adds $2,050 if single or $1,650 per spouse if married. On top of that, the enhanced deduction for seniors (2025 through 2028) allows up to $6,000 per person aged 65+, reduced by 6% of modified AGI above $75,000 (single) or $150,000 (joint) — so it phases out completely at $175,000 single / $250,000 joint. It is taken after AGI, so it does not change how much of your Social Security is taxable.
IRMAA Thresholds (2026)
Medicare Part B and Part D premiums rise with income via IRMAA surcharges. 2026 premiums are based on your 2024 MAGI (two years prior). Surcharges are per person per month, added to the $202.90 standard Part B premium and to your Part D plan premium:
| MAGI (Single) | MAGI (MFJ) | Part B Surcharge/mo | Part D Surcharge/mo |
|---|---|---|---|
| ≤$109,000 | ≤$218,000 | $0 | $0 |
| $109,001–$137,000 | $218,001–$274,000 | +$81.20 | +$14.50 |
| $137,001–$171,000 | $274,001–$342,000 | +$202.90 | +$37.50 |
| $171,001–$205,000 | $342,001–$410,000 | +$324.60 | +$60.40 |
| $205,001–$499,999 | $410,001–$749,999 | +$446.30 | +$83.30 |
| $500,000 or more | $750,000 or more | +$487.00 | +$91.00 |
Frequently Asked Questions
How much of Social Security is taxable?
It depends on combined income (AGI + nontaxable interest + ½ SS). Under $25,000 single / $32,000 MFJ: 0% taxable. $25,000–$34,000 single / $32,000–$44,000 MFJ: up to 50%. Above those: up to 85%.
What is a Roth conversion and why do it in retirement?
A Roth conversion moves pre-tax money to Roth — you pay tax now, get tax-free withdrawals later. Best done in the "gap years" between retirement and RMD onset (ages 60–72) when income is lower. Reduces future mandatory taxable RMDs.
What is IRMAA and when does it apply?
IRMAA is a Medicare Part B and D premium surcharge for higher-income retirees. For 2026 premiums it applies when MAGI (from 2024) exceeds $109,000 (single) / $218,000 (MFJ). The surcharge is per person per month — even the first tier ($81.20/month Part B) costs a married couple $1,948.80/year in extra Part B premiums, before the Part D surcharge.
What is the best bracket to fill with Roth conversions?
Fill the current bracket without pushing into the next. Most retirees in the pre-RMD gap years have lower-than-working income, making the 12% or 22% bracket ideal to fill with conversions before RMDs force higher withdrawals.
Do RMDs change my tax bracket?
Yes. RMDs (starting at age 73) are fully taxable as ordinary income. Large pre-tax balances generate mandatory taxable withdrawals that can push you into higher brackets and make more SS taxable. Pre-RMD Roth conversions reduce this future tax drag.
Does the calculator include the 2026 senior deduction?
Yes. Choose how many filers are 65 or older and the calculator adds the age-65 standard deduction amounts ($2,050 single, $1,650 per married spouse) and the enhanced deduction for seniors — up to $6,000 per person, reduced by 6% of MAGI above $75,000 single / $150,000 joint. Both spouses must file jointly for married couples to claim it.
Are state taxes included?
This calculator shows federal taxes only. Many states fully or partially exempt retirement income and Social Security. Check your state's rules and add the estimated state tax for a complete picture.
Sources & method
This calculator implements the 2026 federal income-tax brackets, standard deduction, age-65 additional deduction and enhanced senior deduction, the IRS Social Security benefit worksheet, and CMS 2026 IRMAA tiers.
Brackets, standard deduction and age-65 amounts: IRS Rev. Proc. 2025-32
Enhanced deduction for seniors ($6,000, 6% phase-out above $75,000 / $150,000): IRS Schedule 1-A (Form 1040), Part V and IRS — Deductions for working Americans and seniors
Social Security taxation ($25,000/$34,000 and $32,000/$44,000 base amounts): IRS Publication 915
IRMAA thresholds and 2026 Part B/Part D surcharges: CMS — 2026 Medicare Parts A & B premiums and deductibles (verified 28 September 2026)
Not financial or tax advice. This is an educational estimator. It does not know your full situation, and tax rules change. Akshaya Panda, who builds and verifies these tools, is an engineer — not a financial adviser, accountant, or tax professional. Before acting on a result that matters, check it with someone licensed to advise you.