Online Calculator

Online Calculator is a free, install-free web calculator with both a Basic and a Scientific mode. From everyday arithmetic and percent conversion to trigonometry, logarithms, roots, and powers, it handles them all and automatically saves your calculation history so you can revisit and reuse results anytime.

Key Features

• Basic mode: addition, subtraction, multiplication, division, decimal point, percent (%), and sign toggle (±) for daily arithmetic.
• Scientific mode: trig functions sin, cos, tan and their inverses asin, acos, atan; logarithms ln and log; square root √, square x², any power xʸ, factorial n!, reciprocal 1/x, absolute value abs, and e^x via exp.
• DEG/RAD switch: trigonometry works in either degrees or radians to suit different habits.
• Constants and last answer: built-in pi (π) and Euler's number (e), plus Ans to insert the previous result for chained calculations.
• Calculation history: every expression and result is saved automatically (up to 50 entries); tap an entry to refill it into the calculator and keep editing.
• Live preview and copy: results preview as you type, and you can copy the current result in one click.
• Keyboard support: type expressions directly, press Enter to calculate and Esc to clear.

Use Cases

• Daily budgeting, shopping totals, and unit or percent conversion.
• Trig and logarithm calculations for students doing homework or reviewing math.
• Quick engineering and science checks for roots, powers, and factorials.
• Multi-step calculations where you need to review intermediate results.

How to Use

1. Switch between "Basic" and "Scientific" at the top as needed.
2. Click the keys or type an expression directly into the input box; the result previews in real time.
3. Press equals (=) or Enter for the final result, which is saved to history automatically.
4. Tap any history entry to refill it into the input and continue editing.

FAQ

Q: Is this calculator free?

A: Yes, completely free. No registration or download is required — just open the page and start.

Q: What is the difference between DEG and RAD?

A: DEG is degrees, the most common in daily use, e.g. sin(30)=0.5. RAD is radians, e.g. sin(π/2)=1. Switch to the mode you need before using trig functions.

Q: Is my history saved? Will it be lost?

A: History is stored locally in your current browser and persists after refresh or close (up to 50 entries). It is lost if you clear browser data or switch device or browser.

Q: Does it work on mobile?

A: Yes. The page is mobile-friendly with larger, easier-to-tap keys and works in both portrait and landscape.

Q: Which operators are supported?

A: Arithmetic (+ − × ÷), percent, parentheses, power (^), factorial (!), and various scientific functions — type them directly or use the on-screen keys.