# Calculators

- 1
- Wikipedia: Calculator
- Encyclopedia article about calculators, including their usage, history and development.

- 2
- Martindale's Calculators
- A collection of calculators for the sciences, business and everyday measurements. Organized by subject area.

- 3
- AbaCal
- An easy to use online platform for applied mathematics which includes an online calculator, a formula library and an exchange platform.

- 5
- AquaCalc
- Convert between various units of measurement, calculate volume and area, convert weight to volume and volume to weight, gravel and mortgage calculators.

- 6
- Binary Calculator
- An arbitrary-precision binary calculator, which adds, subtracts, multiplies, or divides integer and fractional values.

- 8
- Calc
- Online numeral system converter. Supports decimal, hexadecimal, octal, binary numbers, ASCII characters.

- 10
- CalcBuddy
- A math resource website providing an online scientific calculator, and numerous special purpose calculators and unit converters

- 11
- CalcMachine
- Easy to use online calculator and expression evaluator. It supports basic arithmetic, trigonometry and logarithmic functions.

- 12
- CalcNexus
- Provides online calculators for web-enabled mobile phones and PDAs, including financial, fitness and conversion calculators.

- 13
- Calculate Eigenvalues and Eigenvectors
- Calculator for eigenvalues and eigenvectors. Includes a test example and various options.

- 14
- Calculate for Free
- Performs basic math operations, as well as square root and percentages. Includes memory save and recall.

- 17
- Calculator Pi
- Provides functions common in science and engineering. Creates a printable sequence of calculations that can be bookmarked or shared as URL.

- 18
- Calculator Soup
- Free online calculators for finance, math, algebra, fractions, geometry, physics, time and statistics. Converters for common conversions.