Transparent method
The formula
Worked example
Example inputs
How to interpret the result
Spendable retirement income depends on how much of each income source is actually taxable, and that share differs meaningfully by source. A Roth withdrawal, a portion of Social Security, and a traditional account withdrawal can each face a different effective tax treatment even when the raw dollar amounts look identical.
Before you rely on it
What to check
Break income sources apart by their tax treatment before totaling spendable income, rather than applying one flat tax rate across every source.
The common error
Where people go wrong with retirement income tax calculator
Applying a single flat tax rate across every retirement income source as if they were all taxed identically. Taxable, tax-free and partially taxable sources genuinely differ, and blending them into one rate misstates real spendable income.
Sensitivity evidence
How annual taxable withdrawals changes the estimated spendable income
| Annual taxable withdrawals | Estimated spendable income | Estimated income tax |
|---|---|---|
| $32,000 | $72,200 | $4,800 |
| $36,000 | $75,600 | $5,400 |
| $40,000worked example | $79,000 | $6,000 |
| $44,000 | $82,400 | $6,600 |
| $48,000 | $85,800 | $7,200 |
Every input, tested
Which input moves the estimated spendable income most
| Input | Tested from | To | Estimated spendable income at each end | Swing |
|---|---|---|---|---|
| Annual taxable withdrawals | $36,000 | $44,000 | $75,600 to $82,400 | $6,800 (8.6%) |
| Social Security and pension | $27,000 | $33,000 | $76,000 to $82,000 | $6,000 (7.6%) |
| Annual tax-free withdrawals | $13,500 | $16,500 | $77,500 to $80,500 | $3,000 (3.8%) |
| Estimated effective tax rate | 13.0% | 17.0% | $79,800 to $78,200 | $1,600 (2.0%) |
Two variables at once
Estimated spendable income by annual taxable withdrawals and annual tax-free withdrawals
| Annual taxable withdrawals \ Annual tax-free withdrawals | $12,000 | $15,000 | $18,000 |
|---|---|---|---|
| $32,000 | $69,200 | $72,200 | $75,200 |
| $36,000 | $72,600 | $75,600 | $78,600 |
| $40,000 | $76,000 | $79,000 | $82,000 |
| $44,000 | $79,400 | $82,400 | $85,400 |
| $48,000 | $82,800 | $85,800 | $88,800 |
Step by step
The worked example, input by input
| Input | Value used |
|---|---|
| Annual taxable withdrawals | $40,000 |
| Annual tax-free withdrawals | $15,000 |
| Social Security and pension | $30,000 |
| Estimated effective tax rate | 15.0% |
| Estimated spendable income | $79,000 |
| Estimated income tax | $6,000 |
Where the inputs come from
Annual taxable withdrawals are what you take from traditional 401(k)s and IRAs, which are taxed as ordinary income. Annual tax-free withdrawals come from Roth accounts or return of basis. Social Security and pension income are added, though up to 85% of Social Security may be taxable. The effective tax rate is the total tax divided by total income, which is lower than your marginal rate; take it from a recent return or a projection.
Using the estimated spendable income in a real decision
Use it to pick how much to take from each bucket.
When the result stops applying
A single effective rate simplifies a progressive system, so a larger withdrawal changes the effective rate. The estimate ignores state tax, which some states do not levy on retirement income, and the interaction between withdrawals and taxable Social Security. Rules and brackets change, and the temporary lower rates in current law are scheduled to change.
What to compare it with
For the order of withdrawals use the retirement withdrawal order calculator, and for benefit taxation the taxable Social Security page. The IRMAA and Roth conversion calculators show side effects of higher income. The retirement withdrawal page finds the gross amount from a portfolio.
People also ask
Frequently asked questions
Is Social Security taxed?
It can be. Depending on your other income, up to 85% of benefits may be included in taxable income, based on a measure called provisional income.
Are Roth withdrawals taxed?
Qualified Roth withdrawals are tax free, so they add to spendable income without raising taxable income, which helps manage brackets.
Why is my effective rate lower than my bracket?
Because tax is charged in layers. Only the income above each bracket threshold is taxed at the higher rate, so the average rate is lower.