onlinecalculator.me

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.

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Angle:
About this calculator

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

CategoryFunctions
Arithmetic+, −, ×, ÷
Power / rootxʸ, √, ∛, eˣ
Logarithmlog (base 10), ln (natural)
Trigonometrysin, cos, tan, sin⁻¹
Misc1/x, %, n!, π, e
MemoryM+, MR, MC

Keyboard shortcuts

KeyAction
0–9, .Digit / decimal
+ − * /Operators
Enter or =Equals
BackspaceDelete last digit
EscapeClear (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

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).

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