57 calculators · no sign-up · formula explained
Free online calculators: run the numbers and understand the result
57 free online calculators for money, work, school, health and home, in dollars and US units. The result updates as you type, with the formula explained and, when a law or agency sets the numbers, the official source.
Recently used
Why this site exists
A calculator is not just a number: it is an explanation
Most calculators give you a number and stop there. Here every result comes with the formula, an example worked out by hand and, when the numbers come from a law or an agency, the official source, so you can check it and see where every dollar comes from.
Most used
Start with these
Paycheck Calculator
Take-home pay after federal withholding, FICA and 401(k).
$60,000 a year · paid every two weeks · single$1,938.08take-home per paycheck 02Mortgage Calculator
Monthly payment (PITI), total interest and amortization schedule.
Calculate 03Federal Income Tax Calculator 2026
2026 federal tax, effective and marginal rate, refund or balance due.
Calculate 04GPA Calculator
Semester and cumulative GPA from letter grades and credits.
Calculate 05BMI Calculator
Your body mass index and its NHLBI category.
CalculateNew calculators
All calculators
57 calculators in 6 categories
Paycheck and Tax Calculators
- Paycheck Calculator
- Federal Income Tax Calculator 2026
- Overtime Calculator
- Hourly to Salary Calculator
- Self-Employment Tax Calculator
- Freelance Rate Calculator
- Hours Worked Calculator
- Time Calculator
- PTO Planner
- Mileage Reimbursement Calculator 2026
Financial Calculators
- Mortgage Calculator
- House Affordability Calculator
- Loan Calculator
- Auto Loan Calculator
- Credit Card Payoff Calculator
- 401k Calculator
- Social Security Benefits Calculator
- Compound Interest Calculator
- Simple Interest Calculator
- Savings Goal Calculator
- Trump Account Calculator
- Sales Tax Calculator
- Discount Calculator
- Profit Margin Calculator
- Rental Property Calculator
- HSA Contribution Calculator 2026 and 2027
Health Calculators
- BMI Calculator
- Calorie Calculator
- Body Fat Calculator
- Target Heart Rate Calculator
- Pace Calculator
- Due Date Calculator
Everyday Calculators
- Days Between Dates Calculator
- Countdown Calculator
- Age Calculator
- Tip Calculator
- Gas Cost Calculator for a Road Trip
- Paint Calculator for a Room
- Electricity Cost Calculator
- Zodiac Sign Calculator
- Random Number Generator
Math Calculators
- Percentage Calculator
- Proportion Calculator
- Fraction Calculator
- GCF and LCM Calculator
- Quadratic Equation Calculator
- System of Equations Calculator
- Statistics Calculator
- Permutation and Combination Calculator
- Pythagorean Theorem Calculator
- Area Calculator
- Unit Converter
- Fahrenheit to Celsius Converter
- Roman Numeral Converter
News
The latest before you run the numbers
Long Weekends 2027: Every Three-Day Weekend and How to Stretch It
Federal holidays give you 10 long weekends 2027 if you work Monday to Friday and get them all off, and two Thursday holidays that turn into four-day breaks with a single PTO day.
Read moreGift Tax Limit 2026: Give Up to $19,000 per Person Without Gift Tax
The gift tax limit 2026 is $19,000 per person: you can give that much to each friend or relative this year, in cash or presents, without it counting as a taxable gift.
Read moreBonus Tax Rate 2026: How Much Is Withheld From Your Year-End Bonus
The federal bonus tax rate for 2026 is a flat 22% that your employer can withhold, or 37% on bonuses above $1 million in the year, plus the usual 7.65% for Social Security and Medicare.
Read moreCommon questions
Frequently asked questions
Are the calculators free?
Yes. All 57 calculators are free, with no sign-up and no usage limits. The site is funded by advertising, which never changes the results.
Are they built for the United States?
Yes. Amounts are in dollars, measurements in pounds, feet, miles and gallons (with metric where useful), and the tax and labor calculators use the 2026 IRS figures and federal law, each linked to its official source.
Are the results reliable?
Yes, as estimates: each calculator uses the standard formula or the official rule, linked on the page, and is checked against cases worked out by hand. For important decisions, check with the agency or a professional.
Do you store what I type?
No. Everything is calculated in your browser and nothing is sent to a server. If you save a calculation to your history, it stays on your device.
Do the tax calculators include state taxes?
They focus on federal rules, which apply everywhere. Where state taxes matter, such as on a paycheck or a purchase, you can type your state rate, because each state sets its own.
Can I share or download a calculation?
Yes. Every calculator creates a link with your inputs to share, and lets you download the result to Excel or CSV or print it to PDF.
Your next calculation
Missing a calculator?
Tell us what you need to calculate. The most requested ones are the first we build, with their formula, a worked example and the source.