Sources & Methodology

01 Retirement

16 calculators

Federal, military, railroad, and general retirement calculators draw from each program's own governing rules rather than a generic "years times a percentage" approximation.

• FERS Retirement Calculator — built from the Office of Personnel Management's published FERS computation rules, including the High-3 averaging method and age/service annuity multipliers.
• Military Retirement Calculator — reflects 10 U.S.C. §§ 1401, 1401a, and 1408, cross-checked directly against the Department of Defense's own Blended Retirement System comparison calculator and High-3 calculator.
• Railroad Retirement Calculator — the Tier II formula, age-reduction schedule, and 30-year rule are verified against the Railroad Retirement Board's own Tier II computation page.
• TSP Retirement Calculator — agency match formula sourced from TSP.gov.
• Days to Retirement and How Long Will My Retirement Savings Last — Social Security full retirement age table and taxability thresholds sourced from the Social Security Administration.
• Retirement Tax Calculator — Social Security's provisional-income taxability formula, plus 2026 federal brackets and the OBBBA senior bonus deduction, per IRS Revenue Procedure 2025-32.
• State pension calculators (CalPERS, CalSTRS, VRS, NYSLRS, TRS, Florida Retirement System, Ohio PERS/STRS) — built from each system's own published benefit formulas.

02 401(k)

13 calculators

• Contribution limits and match calculators — current-year limits per IRS guidance.
• Inherited 401(k) Beneficiary Calculator — reflects the SECURE Act's 10-year rule and the IRS's July 19, 2024 final regulations clarifying when annual RMDs apply during years 1–9.
• 401(k) Divorce Calculator — marital-share estimates follow standard QDRO coverture-fraction methodology; not a substitute for the actual court order.

03 Tax & Paycheck

26 calculators

• Federal bracket and standard deduction figures — IRS Revenue Procedure 2025-32, the current-year inflation adjustment.
• Quarterly estimated tax / safe harbor rules — the 90%-of-this-year or 100%-of-last-year (110% above $150,000) rule, per the IRS's published estimated tax guidance.
• Gig-work calculators (Uber, Lyft, DoorDash, Instacart, OnlyFans) — self-employment tax calculated at the standard 15.3% rate on net income, per IRS self-employment tax rules.
• State paycheck calculators — each state's current withholding tables and, where applicable, flat-tax rate or no-income-tax status, sourced from that state's department of revenue.

04 Net Worth

8 calculators

• Net Worth Percentile Calculator — household net worth distribution by age bracket sourced from the Federal Reserve's Survey of Consumer Finances.
• Liquid Net Worth Calculator — the liquid-vs-illiquid distinction is separate from, and should not be confused with, the SEC's accredited investor net worth test, which excludes only a primary residence.
• Pension Net Worth Calculator — present-value methodology using standard growing-annuity discounting; life-expectancy defaults reference SSA Period Life Table figures.

05 Capital Gains

19 calculators

• Federal capital gains brackets and the $250,000/$500,000 home sale exclusion — per current IRS rules.
• Inherited and gifted property calculators — reflect the stepped-up basis rule for inherited assets versus carryover basis for gifts, a distinction that materially changes the tax owed.
• State-specific calculators (California, New York, New Jersey, Illinois, and others) — each state's own capital gains tax treatment, layered on top of the federal calculation.

06 HSA

4 calculators

• Contribution limits — IRS Revenue Procedure 2025-19.
• HSA Tax Savings Calculator — FICA figures verified against the Social Security Administration's contribution and benefit base and the SSA's Additional Medicare Tax threshold guidance.
• HSA Withdrawal Penalty Calculator — verified directly against IRS Publication 969.

07 Mortgage Payoff

6 calculators

Built on standard amortization mathematics — the same formulas used industry-wide for loan schedules — rather than a single external regulatory source. Each calculator's default scenario is independently validated against a manually-derived worked example before publishing.

08 Home Insurance

11 calculators

• Replacement Cost Calculator — national average construction cost sourced from the National Association of Home Builders. Underinsurance research references a University of Colorado Boulder analysis of Marshall Fire claims data.
• State-specific calculators (California, Florida, Oklahoma, and others) — reflect each state's dominant risk factor (wildfire, hurricane, hail) in typical premium modeling.

09 Emergency Fund

3 calculators

Standard 3–6 month expense-coverage guidance, consistent with widely-published financial planning recommendations.

10 Debt Payoff

6 calculators

Snowball and avalanche payoff methodology follows standard amortization math applied in the order each strategy defines — smallest balance first (snowball) or highest interest rate first (avalanche).

11 Loan & Finance

7 calculators

• Roof Financing Calculator — FHA Title I Property Improvement Loan program parameters sourced from HUD.
• Deferred vs. Waived Interest — models the retroactive-interest mechanic common to promotional 0% financing offers, based on standard deferred-interest contract terms.
• Auto & Equipment Finance Calculator — current-year Section 179 deduction limits and bonus depreciation rules per IRS guidance.