Research & resources
Trusted articles from universities and professional organizations explaining the math behind the calculators on this site — so you understand the numbers, not just the answer.
A new article is added every week — next one arrives October 26, 2026
The CFPB explains the factors that make up a credit score — payment history, utilization, length of history, and more — and how each one is weighted in the formulas lenders use.
The USDA explains how estimated daily calorie needs are calculated from age, sex, and activity level, and how this relates to BMI and healthy weight ranges used by health calculators.
The FTC outlines how credit card APR is applied to carried balances, how minimum payments stretch repayment over years, and how compound interest works against the borrower when balances are not paid in full.
The EIA explains how residential energy consumption is measured in kilowatt-hours, how utility rates translate into monthly bills, and how to estimate the running cost of an appliance from its wattage.
The IRS breaks down how employers calculate withholding from each paycheck, how the W-4 form controls it, and how adjusting withholding changes your take-home pay and year-end refund or balance due.
The Federal Reserve explains how it tracks inflation, why stable prices matter for the economy, and how interest rate decisions ripple through loans, savings, and the calculators that model them.
The FHFA covers how mortgage interest rates are set, how they affect monthly payments and total loan cost, and what homeowners should weigh when considering refinancing an existing mortgage.
The Department of Labor explains how consistent retirement contributions and compound growth build long-term savings, and why starting early is the single biggest advantage a saver has.
A clear explanation of why margin and markup are not the same — a common source of pricing errors — and how each is calculated from revenue and cost.
The CFPB walks through how APR, loan term, and down payment affect the total cost of a car loan, and why longer terms often cost far more in interest.
How fixed and variable costs interact with price to determine the break-even point — the sales volume at which a business covers all its costs and begins to profit.
Why professional bakers measure ingredients by weight (grams) rather than volume (cups), and how flour density makes cup-to-gram conversion essential for consistent results.
The BLS explains the Consumer Price Index — the benchmark inflation measure — and how rising prices erode the purchasing power of a fixed dollar amount over time.
Research on how households build retirement nest eggs, the role of the 4% withdrawal rule, and how longevity risk shapes savings targets.
NIST covers the SI unit system that underpins every length, weight, and volume conversion, including how metric and imperial units relate.
The IRS outlines how progressive tax brackets work, how marginal rates apply to portions of income, and how standard deductions reduce taxable income.
The Securities and Exchange Commission breaks down compound growth and the quick "Rule of 72" for estimating how long an investment takes to double.
The CDC explains how Body Mass Index is calculated, what the categories mean, and the limitations of using BMI as a sole indicator of health for adults.
A walk through the amortization formula that splits each payment into principal and interest, showing why early payments barely reduce the balance and how term length changes total cost.
How reinvested earnings generate exponential growth over time, and why starting early matters more than how much you invest. A foundational concept behind every retirement and investment calculator.