Smart Calculators. Clear Answers.
Free online calculators for money, math, health, work, and everyday life.
What do you want to calculate?
360 calculators in 12 categories
Featured calculators
Hand-picked starting points. This is an editorial selection, not a popularity ranking.
- Mortgage Payment CalculatorFinancial Planning
- Compound Interest CalculatorFinancial Planning
- BMI CalculatorHealth & Fitness
- Percentage of a Number CalculatorMathematics & Percentages
- Age CalculatorDate, Time & Age
- Loan Payment CalculatorFinancial Planning
- Tip CalculatorUnit Conversion & Everyday Life
- GPA CalculatorEducation & Statistics
- Scientific CalculatorMathematics & Percentages
- Time Zone Conversion CalculatorDate, Time & Age
- IPv4 Subnet CalculatorDigital, Internet & Technology
- Length ConverterUnit Conversion & Everyday Life
Browse by category
- Financial Planning50 calculators
- Home, Property & Mortgages25 calculators
- Business & Accounting35 calculators
- Salary, Payroll & Tax25 calculators
- Mathematics & Percentages35 calculators
- Health & Fitness30 calculators
- Date, Time & Age25 calculators
- Unit Conversion & Everyday Life35 calculators
- Education & Statistics25 calculators
- Science & Engineering25 calculators
- Digital, Internet & Technology25 calculators
- Geometry & Practical Projects25 calculators
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Useful collections
Buying a home
From budget to mortgage, closing costs and prepayment.
Getting out of debt
Plan payoffs and compare strategies.
Running a small business
Pricing, margins, break-even and cash.
Fitness basics
Energy needs, body measures and training.
Students
Grades, GPA, study time and statistics homework.
Network administration
Subnets, masks, ranges and IPv6.
Guides
Guides →- APR, APY, nominal and effective rates: what is the difference?Why a loan and a savings account can both say “5 %” and still mean different things, and how to compare rates fairly.
- How mortgage amortization worksWhy early mortgage payments are mostly interest, how equity builds over time, and what extra payments really do.
- Percentage change, percentage difference and percentage pointsThree ways to compare numbers with percentages — and the common mistakes that make statistics misleading.
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Frequently asked questions
Are Numerith calculators free?
Yes. Every calculator is free to use without an account, registration or email address.
Do you see the numbers I enter?
No. Calculations run entirely in your browser. Inputs are not sent to our servers, logged or used for advertising.
How do you check that results are correct?
Each calculator has automated reference tests computed independently of the site’s code, plus validation tests. The site cannot be built if any test fails. Each page lists its formula, assumptions and verification status.
Can I rely on the results for big decisions?
They are good for planning and learning, but they are estimates based on the inputs and assumptions shown. For financial, tax, medical or engineering decisions, confirm with a qualified professional.
Can I use Numerith offline?
Pages you have visited are cached by your browser so they keep working without a connection.