About Plainsum
Plainsum is a free collection of calculators for everyday money, life, and health questions. Every tool runs in your browser, explains its formula in plain English, and asks for no account or personal details.
What you'll find here
- Money: mortgage, home affordability, auto and personal loans, credit card and debt payoff, compound interest, and retirement savings.
- Taxes and pay: paycheck calculators for all 50 states and Washington, DC, plus federal income tax, self-employment tax, overtime, and the new tips deduction.
- Everyday: sales tax, tips, discounts, percentages, unit conversions, gas cost, GPA, and square footage.
- Health and time: BMI, calories, macros, pregnancy due date, ovulation, age, dates, and hours worked.
Why we made it
Many calculator sites bury the answer under pop-ups, ask for an email address, or give a number without showing where it came from. Plainsum aims to do the opposite: one clear answer, the steps behind it, and a short guide that explains what the number means and what to check next.
How we build calculators
Each calculator uses standard, published formulas, such as the amortization formula for loans and the Mifflin-St Jeor equation for calories. We test results against worked examples and note the assumptions on each page.
Limits
Results are estimates for general information. They are not financial, tax, legal, or medical advice, and they don't account for every rule or personal circumstance. Please confirm important decisions with a qualified professional.
Independence
Plainsum is an independent website. It isn't affiliated with any bank, lender, tax software company, or government agency. The site may show ads to cover its costs, but advertisers have no influence over formulas, results, or articles.
Contact
Found a mistake or want a new calculator? Email [email protected] or see our contact page. You can read more about our sources and review process on How We Calculate.