How taxes are estimated

MangoDime estimates federal and state taxes, Social Security taxation, and required distributions using real 2025 tax rules — simplified in a few specific, disclosed ways.

Federal tax uses the real 2025 income tax brackets and standard deduction ($15,000 single / $30,000 married filing jointly), reused for every future year of your plan — the model doesn't project how brackets might change over time.

Withdrawals from a taxable account are taxed at a flat 15% long-term capital gains rate, but only on the gain portion of what you withdraw, not the whole amount. Pensions are taxed as ordinary income by default (you can mark one as non-taxable). Social Security uses the real IRS provisional-income rule — up to 50% or 85% of your benefit becomes taxable depending on your other income, using the same dollar thresholds as the real tax code, which (like the actual law) aren't adjusted for inflation over time.

State income tax is modeled as a flat rate — each state's own top marginal bracket rate, applied to your taxable income and gains. That's a real simplification: it tends to overstate what you'd actually owe in a state with a progressive tax structure, since most income doesn't get taxed at the very top rate.

Required minimum distributions (RMDs) start at 73 or 75, depending on your birth year, using the real IRS Uniform Lifetime Table, tracked separately for each spouse. Medicare's IRMAA surcharge is estimated using your same-year income (the real rule actually looks back two years), and ACA marketplace subsidies are estimated against a national-average benchmark premium rather than your actual county's rate.