# Free online scientific calculator

> A scientific calculator handles more than basic arithmetic — trig functions, logs, powers, factorials, and memory. This one works with your keyboard too.

A full-featured scientific calculator with trigonometry, logarithms, exponents, factorials, memory functions, and keyboard support. Degrees and radians mode.

**Interactive version:** https://onlinecalculator.me/math/scientific/
**Category:** Math

## How to use

1. Type numbers using the buttons or your keyboard.
2. Press a function button (sin, log, √, etc.) to apply it to the current value instantly.
3. For binary operations (×, +, −, ÷, xʸ), enter the first number, press the operator, enter the second number, then press =.
4. Use the expression display at the top to track your running calculation.

## Supported operations

| Category | Functions |
|---|---|
| Arithmetic | +, −, ×, ÷ |
| Power / root | xʸ, √, ∛, eˣ |
| Logarithm | log (base 10), ln (natural) |
| Trigonometry | sin, cos, tan, sin⁻¹ |
| Misc | 1/x, %, n!, π, e |
| Memory | M+, MR, MC |

## Keyboard shortcuts

| Key | Action |
|---|---|
| 0–9, . | Digit / decimal |
| + − * / | Operators |
| Enter or = | Equals |
| Backspace | Delete last digit |
| Escape | Clear (AC) |

## Worked examples

### sin(45°) — degrees mode

1. Make sure **DEG** is selected (top toggle).
2. Press `4` `5` then `sin`.
3. Result: **0.7071067812** *(= √2 / 2)*

### Natural log of 10

1. Press `1` `0` then `ln`.
2. Result: **2.302585093**

Useful because `ln(10) ≈ 2.303` is the bridge between the two log bases: `log₁₀(x) = ln(x) / ln(10)`.

### Compound a $10,000 investment at 7% for 20 years

Formula: A = P × (1 + r)ⁿ

1. Enter `1.07` then press `xʸ`.
2. Enter `20` then press `=`. Result: **3.8697**
3. Multiply by `10000` → `=`. Result: **$38,697**

### 8! (factorial)

1. Enter `8` then press `n!`.
2. Result: **40,320** *(8 × 7 × 6 × 5 × 4 × 3 × 2 × 1)*

## Notes

- **DEG vs. RAD** — the most common source of wrong answers. If sin(90) returns 0.894 instead of 1, you're in RAD mode and need to switch to DEG.
- **Operator precedence** — this calculator evaluates left-to-right as you type, like a standard physical scientific calculator. For strict algebraic order (PEMDAS), group with parentheses or compute inside expressions step by step.
- **Results are rounded** to 10 significant digits to avoid floating-point noise.
- **Factorial** is limited to integers 0–170. Above 170, factorial exceeds JavaScript's maximum float.
- The calculator is stateless — there is no URL sharing because there are no persistent inputs.

## Frequently asked questions

### What functions are supported?

Trigonometry: sin, cos, tan, and their inverses (sin⁻¹, cos⁻¹, tan⁻¹). Logarithms: log₁₀ and natural log (ln). Exponents: eˣ, xʸ. Roots: √ (square root), ∛ (cube root). Other: 1/x (reciprocal), % (percent), n! (factorial), and the constants π and e.

### How do I use degrees vs. radians?

Use the DEG / RAD toggle at the top. In DEG mode, trig functions expect degrees (sin(90) = 1). In RAD mode, they expect radians (sin(π/2) = 1). The toggle also affects inverse trig outputs.

### What does the % button do?

If you're in the middle of a calculation (e.g., 200 + 15%), pressing % converts the pending number to that percentage of the accumulated value — same as how a physical calculator works. Standalone, it divides by 100.

### How does memory work?

M+ adds the current display value to memory. MR recalls memory to the display. MC clears memory to zero.

### Can I use the keyboard?

Yes. Number keys (0–9), decimal point (.), operators (+, −, *, /), Enter or = for equals, Backspace for delete, and Escape for AC (all clear).

## Sources

- [Order of operations (PEMDAS/BODMAS)](https://en.wikipedia.org/wiki/Order_of_operations) — Wikipedia
- [Trigonometric functions](https://en.wikipedia.org/wiki/Trigonometric_functions) — Wikipedia

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