Planning Calculators

The percentage of a portfolio withdrawn in a year to fund spending — the working answer to the question of how much a portfolio can sustainably pay out. Research on withdrawal rates studies how a starting rate, adjusted for inflation each year, would have held up across historical market sequences, including the bad ones.

The danger that poor market returns early in retirement, combined with ongoing withdrawals, permanently impair a portfolio — even if long-run average returns turn out fine. Two retirees can earn the same average return in a different order and end up in very different places. It is the reason the first years of retirement carry outsized weight in income planning.

The division of a portfolio among asset classes — stocks, bonds, cash — in proportions matched to goals, time horizon, and tolerance for decline. Allocation is the primary lever controlling how far a portfolio can fall in a bad year and how much it can grow over a good decade; the selection of individual investments operates within the range allocation sets.

Spreading investments across holdings, sectors, and asset classes so that no single failure determines the outcome. Diversification does not prevent losses in a broad downturn; its job is narrower and more valuable — removing the risks specific to any one company or bet, leaving only the market risk an investor is actually compensated for taking.

A range of taxable income taxed at a single rate. The federal system is progressive — seven brackets running from 10 to 37 percent in 2026 — and only the income inside each bracket is taxed at that bracket's rate. Crossing into a higher bracket never reduces take-home income; only the dollars above the line pay the higher rate.

The marginal rate is the tax on the next dollar of income — the rate of the bracket that dollar lands in. The effective rate is total tax divided by total income, and it is always lower, because earlier dollars were taxed in lower brackets. Decisions like sizing a Roth conversion turn on the marginal rate, not the effective one, because they are decisions about the next dollar.

The age at which a worker qualifies for their full, unreduced Social Security benefit — 67 for everyone born in 1960 or later. Claiming earlier permanently reduces the monthly check: at 62, the benefit is 70 percent of the full amount for someone with an FRA of 67. Waiting past FRA earns delayed retirement credits until age 70, where the benefit reaches 124 percent.

The increase Social Security applies for each month a worker delays claiming past full retirement age, accruing at 8 percent per year until age 70, after which there is no further growth. For someone with a full retirement age of 67, a benefit claimed at 70 is 124 percent of the full amount — a permanently larger check that also receives larger dollar cost-of-living adjustments each year.

The movement of money from a traditional IRA or 401(k) into a Roth IRA. The converted amount is taxed as ordinary income in the year of the conversion; in exchange, it then grows tax-free and carries no required minimum distributions during the owner's lifetime. The math turns on the difference between the tax rate paid at conversion and the rate that would otherwise apply to the same dollars later.

Short for income-related monthly adjustment amount — a surcharge added to Medicare Part B and Part D premiums for higher-income households. In 2026 it begins when modified adjusted gross income exceeds $109,000 for single filers or $218,000 for joint filers, measured from the tax return two years prior. IRMAA is a cliff, not a slope: crossing a threshold by a single dollar triggers the full surcharge for that tier.