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Pension Lump Sum Tax Impact Estimator

The Pension Lump Sum Tax Impact Estimator shows how a one-time pension distribution may change after applying user-entered taxable share and tax-rate assumptions. It separates ordinary tax on the taxable portion from any additional distribution tax or penalty rate you choose to model, then reports the estimated after-tax amount.

Pension tax treatment can depend on rollover choices, cost basis, age, plan type, jurisdiction, and individual circumstances. For that reason, this calculator does not embed a statutory tax bracket or assume that an additional tax automatically applies; you supply the rates that fit the scenario you are evaluating.

Inputs

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Result
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Estimated after-tax lump sum
Taxable amount—
Estimated ordinary tax—
Additional tax / penalty—
Total modeled tax—

1. Enter the distribution
Use the gross pension lump sum you want to evaluate.

2. Set the taxable share
Enter the percentage of the distribution you expect to be taxable under your circumstances.

3. Enter marginal tax assumptions
Provide federal and state/local rates for the taxable portion.

4. Add any extra distribution tax
If you are intentionally modeling an additional tax or penalty, enter that rate; otherwise leave it at 0%.

5. Review the net amount
Compare the estimated tax components with the after-tax lump sum available for your plan.

Formula:

Taxable amount = Distribution × Taxable share Ordinary tax = Taxable amount × (Federal rate + State/local rate) Additional tax = Distribution × Additional rate After-tax amount = Distribution − Ordinary tax − Additional tax

All rates are converted from percentages to decimals. The model is deliberately simplified and does not calculate progressive brackets, deductions, credits, basis recovery rules, withholding, or rollover treatment.

What the result means

The result is the gross distribution less the taxes and additional rate you explicitly entered. It is a scenario estimate rather than a tax return calculation.

Confirm actual pension distribution taxation with current plan documents and qualified tax guidance before acting on a lump-sum election.

Given: $250,000 distribution, 100% taxable share, 22% federal rate, 5% state/local rate, and no additional tax.

Calculation: taxable amount = $250,000. Ordinary tax = $250,000 × 27% = $67,500. Additional tax = $0.

Result: estimated after-tax lump sum = $250,000 − $67,500 = $182,500.

The estimate uses marginal-rate assumptions and should not be read as the exact tax liability on a real return.

Does this calculator know my actual tax bracket?

No. You enter the rates yourself. Actual tax can differ because taxable income is subject to brackets and may interact with deductions, credits, and other income.

What should I enter for taxable share?

Use the portion you reasonably expect to be taxable based on your plan and tax circumstances. If you are unsure, review the plan’s distribution information or consult a qualified tax professional.

Should a rollover be entered as a taxable cash distribution?

Not automatically. Eligible rollover treatment can differ from taking cash, so model the transaction you actually expect rather than assuming the full amount is immediately taxable.

Why is the additional rate separate?

It lets you test a penalty or other additional distribution tax without treating it as ordinary income tax. Leave it at 0% when it does not apply to your scenario.

Is withholding the same as tax owed?

No. Withholding is a prepayment toward tax liability. The calculator estimates tax from the rates you enter and does not model withholding mechanics.