All Calculators
Browse calculators grouped by category to find the tool you need.
Finance
Net Present Value (NPV) Calculator
Calculate the net present value (NPV) of an investment or project. Enter your initial investment, discount rate, and future cash flows to see if your project is profitable.
Credit Card Payoff Calculator
Estimate how long it will take to pay off your credit card debt, or what payment you need to be debt-free by a target date. See your interest, payoff time, and a full schedule.
Loan Interest Calculator
Estimate your monthly loan payments and total interest cost.
Boat Payment Calculator
Estimate monthly boat loan payments given purchase price, down payment, interest rate and term.
Tip Calculator
Quick tip & split calculator for dining and shared bills.
Mortgage Payment Calculator
Estimate monthly mortgage payments and view an amortization schedule.
Health & Fitness
Statistics
Mathematics
Inequality Solver
Solve simple linear inequalities of the form ax + b [<, <=, >, >=] 0 and get interval solutions.
Decimal to Fraction Calculator
Convert decimal numbers to a simplified fraction or mixed number.
Area of a Circle
Calculate the area of a circle given its radius using A = πr².
Circumference Calculator
Compute the circumference (perimeter) of a circle given the radius.
Surface Area Calculator
Calculate the surface area of a rectangular prism (box).
Perimeter Calculator
Compute the perimeter for rectangles, squares, and simple isosceles triangles.
Law of Sines Calculator
Use the Law of Sines to compute missing sides or angles in a triangle (a/sin(A) = b/sin(B)).
Engineering
Utilities
Date Difference Calculator
Calculate days, or years-months-days between two dates. Inclusive or exclusive end date option.
Time Difference Calculator
Compute elapsed time between two times (hours, minutes, seconds). Option to wrap to next day.
Basic Calculator
A simple online basic calculator for quick arithmetic and percent operations.
Unit Converter
Convert lengths, masses, volumes, areas and temperatures between common units.