purr.tools

Free Online Tools — Private & Secure

A collection of free, browser-based utilities. Everything runs in your browser — share any calculation via a unique link, or embed any tool directly on your website.

Runs entirely in your browserShareable calculation linksEmbeddable on any website

Volume Converters

Finance Tools

Mortgage Calculator
Calculate your monthly mortgage payment and total cost. Everything runs in your browser — your data never leaves your device.
Loan Calculator
Enter your loan amount, annual interest rate, and term to instantly calculate your monthly payment and total cost.
Car Loan Calculator
Enter vehicle price, down payment, trade-in value, interest rate, and loan term to calculate your monthly payment.
Compound Interest Calculator
Calculate how your investment grows with compound interest.
Paycheck Calculator
Enter your gross pay and tax rates to calculate your net take-home pay and annual deductions.
Tip Calculator
Enter your bill, choose a tip percentage, and split the total among your group.
Inflation Calculator
Enter an amount, annual inflation rate, and number of years to see how inflation erodes purchasing power.
Investment Calculator
Enter your investment details to see how your money grows over time.
Tax Calculator
Enter your gross income, any deductions, and your tax rate to estimate your tax liability.
Retirement Calculator
Enter your age, savings, monthly contribution, and expected return to project your retirement nest egg.
Amortization Calculator
Enter your loan amount, interest rate, and term to see monthly payments and a full payment-by-payment breakdown.
Mortgage Payment Calculator
Calculate your monthly mortgage payment including principal, interest, taxes, insurance, and PMI.
401k Calculator
Project your 401k balance at retirement based on your salary, contributions, employer match, and investment returns.
Sales Tax Calculator
Calculate the tax amount and total price from a pre-tax price, or find the pre-tax price from a total using reverse mode.
Salary to Hourly Calculator
Enter your annual salary, hours per week, and working weeks per year to see your equivalent hourly, daily, weekly, and monthly rates.

Health Tools

Text Tools

Generators

Education Tools

Network Tools

Math Tools

Percentage Calculator
Three common percentage calculations in one place.
Concrete Calculator
Enter your slab dimensions to calculate the volume of concrete needed.
Derivative Calculator
Enter a polynomial expression to compute its derivative using the power rule. Supports sums and differences of terms like 3x^2 + 2x - 5.
Standard Deviation Calculator
Enter a list of numbers to instantly compute mean, standard deviation (population and sample), variance, min, max, range, sum, and count.
Quadratic Formula Calculator
Solve ax² + bx + c = 0. Enter the coefficients to find the roots instantly.
Triangle Calculator
Enter all three side lengths to calculate each angle, the area, and the perimeter.
Square Root Calculator
Enter a number to calculate its square root. Change the root degree for cube root (3), fourth root (4), or any nth root.
Slope Calculator
Enter two points to calculate the slope (rise over run), y-intercept, line equation, and distance between the points.
Factor Calculator
Enter a whole number to find all its factors and its prime factorization.
Percentage Increase Calculator
Enter the original and new values to calculate the percentage change, absolute difference, and multiplication factor.
Z-Score Calculator
Enter a value, the population mean, and standard deviation to calculate the z-score and percentile rank.
Long Division Calculator
Enter a dividend and divisor to see the full step-by-step long division with quotient and remainder.
Right Triangle Calculator
Enter any two sides to calculate the third side, all angles, area, and perimeter of a right triangle.
Square Footage Calculator
Enter the length and width in feet to calculate the area in square feet, square meters, square yards, and square inches.
Percent Change Calculator
Enter the original value and the new value to calculate the percentage change.
Pythagorean Theorem Calculator
Enter any two sides of a right triangle to solve for the third using a² + b² = c².

Temperature Converters

Length Converters

Time Tools

Security Tools

Lookup Tools

Weight Converters

Productivity Tools

Games

Developer Tools