How we make our numbers

Every calculator on this site runs on published government formulas, not on our opinions. This page lists the formulas, the assumptions, and where each number comes from, so you (or your advisor, or your lawyer) can check our work. When something varies by state or by judge, we show a range and say so. We never present a range as a promise.

Social Security estimator

• Benefit formula: 2026 bend points of $1,286 and $7,749 with the 90% / 32% / 15% brackets, from SSA's published table. Earnings above the 2026 taxable maximum of $184,500 (SSA) don't count toward benefits.
• Ex-spouse benefit: up to 50% of the worker's full-retirement-age amount, reduced for early claiming by 25/36 of 1% per month for the first 36 months and 5/12 of 1% per month beyond, exactly as published by SSA's actuaries. At 62 with a full retirement age of 67, that works out to 32.5% of his amount.
• Own-benefit reductions and delayed credits: 5/9 of 1% per early month (first 36), 5/12 of 1% beyond; delayed credits of 2/3 of 1% per month after full retirement age, through 70.
• Dual entitlement past full retirement age: delayed credits on your own benefit reduce the ex-spouse portion payable dollar for dollar, so the combined total after 67 is the larger of (your full amount plus the top-up) and (your own amount with credits). This follows SSA's operating manual, POMS RS 00615.694.
• Eligibility timing in the paid plan: when the ex-spouse portion cannot legally start until later (final divorce, the two-continuous-year rule when the ex is not yet entitled, or the ex turning 62), the plan credits it only from that start. Because we ask for years rather than exact dates, delayed figures use the cautious end of the window (floors, not ceilings), delayed credits earned in a year are counted from the following January, and a break-even that depends on the exact dates is shown as a range instead of a single age.
• We assume full retirement age is 67, which is true for everyone born in 1960 or later, meaning every reader aged 40 to 60 in 2026.
• When you enter a typical income instead of a benefit figure, we approximate the average indexed monthly earnings as that income divided by 12, capped at the taxable maximum. This "steady career" approximation is an editorial simplification, not SSA's method: the real computation indexes your highest 35 years (zeros count) and uses the formula for the year you turn 62, whose future bend points nobody knows yet. Treat income-based results as a today's-dollars scenario. Your own Social Security statement beats any calculator, ours included. Citing SSA sources means we checked our arithmetic against their published rules; it does not mean SSA has reviewed or endorsed this site.

Marital share estimator

• 401(k) and IRA accounts use the subtraction method: today's balance minus the balance on the wedding date. States treat growth on the premarital portion differently, so we flag it rather than pretending one rule fits all.
• Pensions use the coverture (time-rule) fraction: months married during plan participation divided by total participation months.
• Division of the marital portion: community property states start from 50/50; equitable distribution states aim for "fair, not necessarily equal," so we show a 40% to 60% band, never a point estimate.
• QDRO flag: employer plans governed by ERISA (401(k), 403(b), private pensions) require a qualified domestic relations order to divide; IRAs divide through the divorce decree instead, per IRS guidance.

House vs. 401(k) comparison

• Traditional 401(k) dollars are compared after your marginal tax rate, because withdrawals are taxed as ordinary income.
• House equity is compared after assumed selling costs of 7% of the home value (adjustable), and we flag when a projected gain exceeds the $250,000 single-filer exclusion on a primary home under IRS Topic 701.

Retirement runway

• A month-by-month simulation in today's dollars using a real (after inflation) return, default 3% per year, adjustable. Income streams (Social Security, pension, support, work) start and stop at the ages you set. We simulate to age 95 and also compute the spending level that lasts exactly to 95.

What we don't do

We don't predict what a judge will decide, we don't calculate spousal or child support (state formulas vary too much to estimate honestly), and we don't give legal or personalized financial advice. Our calculators organize your numbers so that the expensive hours you may buy later are spent on judgment, not arithmetic.

Corrections log

When we find an error, we fix it and record it here rather than pretending it never happened.

• September 6, 2026: After an external expert review, we corrected the Social Security estimator and Claiming Plan for claims after full retirement age with both an own benefit and an ex-spouse portion. We previously added delayed credits on top of the full ex-spouse portion; SSA's rule (POMS RS 00615.694) offsets the ex-spouse portion by those credits, which lowers the age 68 to 70 figures in those cases. The same update added eligibility-timing questions (final divorce, his age, whether he has filed), the year-you-reach-67 earnings-test rule, and clearer labeling of income-based figures as scenarios.

Found an error? We want to know: every page shows its last update date, and we recheck sources when the government publishes new figures each year.