How to use the calculator

Last reviewed on 30 April 2026.

The calculator works the way most people expect: type a calculation, press equals, read the answer. This page goes a step further and covers the bits that are not obvious — keyboard input, the DEG and RAD modes, the SCI panel, the history list, and the small differences from a physical calculator. If you only have a minute, read the keyboard table; the rest is reference.

The basics in three steps

Type the calculation. Use either the on-screen keys or your keyboard. As you type, a live preview of the answer appears in the display.
Press = or Enter. The expression and the result are saved to history.
Start the next calculation. Typing a digit clears the previous result; typing an operator continues from it.

Keyboard shortcuts

Every action has a keyboard equivalent so you can keep your hands on the keys.

Key	What it does
`0`–`9`	Insert a digit
`.` or `,`	Decimal point
`+` `-` `*` `/`	Add, subtract, multiply, divide
`%`	Percent (see the % key explained)
`^`	Power (`2^10` = 1024)
`(` `)`	Parentheses for grouping
`Enter` or `=`	Calculate
`Backspace`	Remove the last character or function name
`Esc` or `Delete`	Clear everything (AC)

Functions like sin, log, and sqrt do not have single-key shortcuts. Tap them on the SCI panel and they are inserted as sin(, log(, or sqrt( with the cursor inside the parentheses.

The display and the live preview

The display has two lines. The top line shows the expression you are building, with multiplication shown as ×, division as ÷, and π and √ in their familiar shapes. The bottom line shows the live result. As long as the expression is well formed, the result updates while you type — useful for catching mistakes before pressing equals.

If the expression is incomplete (an open parenthesis, a trailing operator), the live preview keeps the last valid value rather than blanking out. When you press equals, missing closing parentheses are added automatically so a half-typed sin(0.5 still evaluates.

DEG and RAD

Two pills sit above the display. DEG means trigonometric functions interpret their argument as degrees; RAD means radians. The mode applies to sin, cos, tan, and the inverse trig keys. It does not change anything else. Picking the wrong mode is the single most common reason a result looks wrong; if you are not sure which one you need, see degrees vs radians.

The SCI panel

The third pill toggles the scientific panel. On wider screens it is open by default; on phones it starts closed to keep the standard keypad larger. Inside the panel:

Trigonometry: sin, cos, tan and their inverses sin⁻¹, cos⁻¹, tan⁻¹.
Logarithms: log for base 10, ln for natural log. See log vs ln if you are not sure which to use.
Exponentials: 10ˣ, eˣ, and xʸ for arbitrary powers.
Roots: √ for square root and ∛ for cube root. Higher roots can be written as fractional powers, for example 32^(1/5).
Other: factorial x!, absolute value |x|, reciprocal 1/x, and the constants π and e.

History

Every successful calculation is added to the history list at the bottom of the page, newest first. Click any entry and its result becomes the starting point for a new calculation; a fresh expression replaces it, an operator continues from it. The list keeps the most recent fifty entries and resets when you reload the page.

How the percent and power keys actually behave

The percent key on this calculator is a literal divide-by-one-hundred. Typing 200 + 10% is the same as 200 + 0.1, which equals 200.1. Some physical calculators interpret the same keystrokes as "10% of 200, then add", giving 220. Neither is wrong, but they are different. The full breakdown is in using the % key.

The power key uses standard right-associativity: 2^3^2 means 2^(3^2) = 512, not (2^3)^2 = 64. If in doubt, use parentheses.

Common mistakes

Wrong trig mode. If sin(30) gives roughly -0.988, you are in RAD when you wanted DEG.
Missing parentheses. 1/2+3 is 3.5, not 0.2. Group the denominator: 1/(2+3).
Negative bases under fractional powers. (-8)^(1/3) can return a complex number on some calculators; this one returns the real cube root for the dedicated ∛ key only.
Implicit multiplication. Type 2*pi, not 2pi. The parser does not assume an invisible times sign.
Comma versus dot. Both , and . insert a decimal point. Thousand separators in the result are display-only; you cannot type them.

Accessibility notes

The display uses ARIA live regions, so screen readers announce the live preview and the final result. Every button is keyboard focusable. The colour scheme follows your operating system preference and switches between dark and light automatically. If anything blocks you from using the calculator with assistive technology, please write to [email protected].