Windows Calculator

Until Windows 95, it uses an IEEE 754-1985 double-precision floating-point, and the highest representable number by the calculator is 2¹⁰²⁴, which is slightly above 10³⁰⁸ (~1.80 × 10³⁰⁸).

In Windows 98 and later, it uses an arbitrary-precision arithmetic library, replacing the standard IEEE floating point library.[3] It offers bignum precision for basic operations (addition, subtraction, multiplication, division) and 32 digits of precision for advanced operations (square root, transcendental functions). The largest value that can be represented on the Windows Calculator is currently <10^10,000 and the smallest is 10^−9,999. (Also ! calculates the Gamma function which is defined over all real numbers, only excluding the negative integers).

In Windows 2000, digit grouping is added. Degree and base settings are added to menu bar.

The calculators of Windows XP and Vista were able to calculate using numbers beyond 10¹⁰⁰⁰⁰, but calculating with these numbers (e.g. 10^2^2^2^2^2^2^2...) does increasingly slow down the calculator and make it unresponsive until the calculation has been completed.

These are the last versions of Windows Calculator, where calculating with Binary/Decimal/Hexadecimal/Octal numbers is included into scientific mode. In Windows 7, they were moved to programmer mode, which is a new separate mode that co-exists with scientific mode.

Windows 7 Calculator

In Windows 7, separate programmer, statistics, unit conversion, date calculation and worksheets modes were added. Tooltips were removed. Furthermore, Calculator's interface was revamped for the first time since its introduction. The base conversion functions were moved to the programmer mode and statistics functions were moved to the statistics mode. Switching between modes does not preserve the current number, clearing it to 0.

The highest number is now limited to 10¹⁰⁰⁰⁰ again.

In every mode except programmer mode, one can see the history of calculations. The app was redesigned to accommodate multi-touch. Standard mode behaves as a simple checkbook calculator; entering the sequence 6 * 4 + 12 / 4 - 4 * 5 gives the answer 25. In scientific mode, order of operations is followed while doing calculations (multiplication and division are done before addition and subtraction), which means 6 * 4 + 12 / 4 - 4 * 5 = 7.

In programmer mode, inputting a number in decimal has a lower and upper limit, depending on the data type, and must always be an integer. Data type of number in decimal mode is signed n-bit[4] integer when converting from number in hexadecimal, octal, or binary mode.

Windows 8.1's additional Metro-style calculator in standard mode

On the right of the main Calculator, one can add a panel with date calculation, unit conversion and worksheets. Worksheets allow one to calculate a result of a chosen field based on the values of other fields. Pre-defined templates include calculating a car's fuel economy (mpg and L/100 km),[5] a vehicle lease, and a mortgage. In pre-beta versions of Windows 7, Calculator also provided a Wages template.

While the traditional Calculator is still included with Windows 8.1, a Metro-style Calculator is also present, featuring a full-screen interface as well as normal, scientific, and conversion modes.[6]

The Calculator in non-LTSC editions of Windows 10 is a Universal Windows Platform app. In contrast, Windows 10 LTSC (which does not include universal Windows apps) includes the traditional calculator, but which is now named win32calc.exe. Both calculators provide the features of the traditional calculator included with Windows 7, such as a unit conversions for volume, length, weight, temperature, energy, area, speed, time, power, data, pressure and angle, and the history list which the user can clear.

Both the universal Windows app and LTSC's win32calc.exe register themselves with the system as handlers of a 'calculator:' pseudo-protocol. This registration is similar to that performed by any other well-behaved application when it registers itself as a handler for a filetype (e.g. .jpg) or protocol (e.g. http:).

All Windows 10 editions (both LTSC and non-LTSC) continue to have a calc.exe, which however is just a stub that launches (via ShellExecute) the handler that is associated with the 'calculator:' pseudo-protocol. As with any other protocol or filetype, when there are multiple handlers to choose from, users are free to choose which handler they prefer— either via the classic control panel ('Default programs' settings) or the immersive UI settings ('Default Apps' settings) or from the command prompt via OpenWith calculator:.

In the Windows 10 Fall Creators Update, a currency converter mode was added to Calculator.[7]

On 6 March 2019, Microsoft released the source code for Calculator on GitHub under the MIT License.[8]