Online Calculator – Free Scientific, Financial & Unit Calculator🧮 Calculator
🧮 Free Online Calculator
Free Online Calculator
Scientific, financial, and unit conversion calculator — all in one free tool. No download, no sign-up.
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Free Online Calculator — Complete Guide
This free online calculator provides three powerful modes in a single tool. Whether you need to perform quick arithmetic, evaluate scientific expressions, or convert between units, everything is available instantly in your browser with no download required.
Calculator Features
🔢 Basic Calculator
Addition, subtraction, multiplication, division, percentage, and sign toggle. Stores calculation history.
🔬 Scientific Mode
Trigonometric functions (sin, cos, tan), logarithms (log, ln), square roots, powers, π, e, and parentheses.
📐 Unit Converter
Convert length, weight, temperature, volume, and area between metric and imperial units instantly.
📋 History
Last 5 calculations shown below the display. Tap any history entry to recall the result.
Keyboard Shortcuts
The online calculator fully supports keyboard input. Press number keys and operators directly. Press Enter or = to calculate. Press Escape to clear. Press Backspace to delete the last character. Use parentheses ( and ) for grouping.
🧮 Pro tip: For compound interest calculations in basic mode, use the scientific mode’s power function: enter Principal × (1 + rate)^years to calculate compound growth directly.
Switch to Scientific mode using the tab at the top. Enter a number, then press a function button (sin, cos, sqrt, etc.) to apply it. For trigonometric functions, enter the angle in degrees first. For powers, enter the base number, press xʸ, then enter the exponent and press =. Use parentheses to group complex expressions.
The scientific calculator uses degrees by default for sin, cos, and tan calculations. The internal conversion to radians is handled automatically. So sin(90) = 1, cos(0) = 1, and tan(45) ≈ 1, as expected in degree mode.
Select the conversion type from the dropdown, then enter a value in either field. The opposite field updates automatically in real time. Conversions work bidirectionally — enter the source value in either field to convert in either direction.
Yes, this online calculator is fully responsive and works on all modern mobile browsers including Safari (iOS) and Chrome (Android). The touch-friendly button sizes make it easy to use on small screens. No app download is required.