Progressive Tax Bracket Planner

Household Inputs

Gross annual income $85,000

Pre-tax 401(k) / IRA contribution $6,000

Filing Status

Results

Taxable income

Federal tax owed

Marginal rate

Effective rate

Bracket Breakdown

How it works

The U.S. federal income tax is progressive: income is sliced into brackets, and only the slice that falls inside a bracket is taxed at that bracket's rate — not the whole income.

taxable = max(0, gross − standard deduction − pre-tax contributions)
tax = Σ rate_i × clamp(taxable, min_i, max_i) − min_i   (per bracket, ≥ 0)
marginal rate = rate of the bracket containing the last dollar earned
effective rate = tax ÷ gross income

Gross income slider — total earnings before any adjustments.
Pre-tax contribution slider — money routed into a 401(k)/IRA before tax, directly shrinking taxable income (and therefore the top brackets it can reach).
Filing status — swaps both the bracket thresholds and the standard deduction between Single and Married Filing Jointly.
Each 3D tower is a coin stack of the actual dollars taxed inside that bracket; the glowing marker on the ruler shows exactly where taxable income lands.

Simplified for teaching: uses 2024 IRS single/MFJ brackets and standard deductions, ignores credits, phase-outs, state tax, and payroll tax. Not tax advice.

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