Full trig, logs, memory, 2nd shift functions, DEG/RAD mode, and keyboard support — the calculator that works the way you think.
This calculator combines the full function set of a physical scientific calculator with the convenience of a browser-based tool that works identically on desktop, tablet, and mobile. You can type expressions directly using your keyboard or tap the on-screen buttons — both methods work simultaneously. Expressions are evaluated left-to-right respecting standard mathematical order of operations: parentheses first, then exponents, then multiplication and division, then addition and subtraction.
The 2nd button (top right of the mode bar) activates a second layer of functions. When 2nd is active, the function buttons shift: sin becomes sin⁻¹ (arcsine), cos becomes cos⁻¹ (arccosine), tan becomes tan⁻¹ (arctangent), log becomes 10ˣ (ten to the x), ln becomes eˣ (e to the x), √ becomes ∛ (cube root), x² becomes x³, and xʸ becomes ʸ√x (nth root). After pressing a shifted function, 2nd automatically deactivates. The yellow highlight on shifted buttons makes the active state obvious.
The DEG/RAD toggle controls how trigonometric functions interpret angles. DEG mode means sin(90) = 1 (90 degrees). RAD mode means sin(π/2) = 1 (pi/2 radians). The current mode is shown in the display badge and in the angle toggle. This setting also automatically affects inverse trig output — in DEG mode, asin(1) returns 90 (degrees); in RAD mode it returns π/2.
Degrees and radians are two ways to measure angles. A full circle is 360° or 2π radians. The conversion is: radians = degrees × π/180. In everyday contexts — geometry, navigation, surveying, architecture — degrees are more intuitive. In calculus, physics, and higher mathematics, radians are preferred because the derivative of sin(x) is cos(x) only when x is in radians.
The unit circle provides the key reference values for trig functions. At 0° (0 rad): sin = 0, cos = 1, tan = 0. At 30° (π/6 rad): sin = 0.5, cos = √3/2 ≈ 0.866. At 45° (π/4 rad): sin = cos = √2/2 ≈ 0.707. At 60° (π/3 rad): sin = √3/2, cos = 0.5. At 90° (π/2 rad): sin = 1, cos = 0, tan = undefined (vertical). These values are worth memorizing for quick mental math.
Inverse trig functions return angles: asin(0.5) asks "what angle has a sine of 0.5?" The answer is 30° (in DEG mode) or π/6 ≈ 0.5236 (in RAD mode). Range restrictions apply: asin and acos return values in [-90°, 90°] and [0°, 180°] respectively; atan returns values in (-90°, 90°).
The common logarithm (log, base 10) asks "what power of 10 gives this number?" log(1000) = 3 because 10³ = 1000. log(0.01) = -2 because 10⁻² = 0.01. It appears in the pH scale (pH = -log[H⁺], so a 10× increase in acidity drops pH by 1), decibels (dB = 10 log(P/P₀), the logarithmic sound measurement), and the Richter scale for earthquakes (each whole number increase represents 10× more ground motion amplitude).
The natural logarithm (ln, base e) uses Euler's number e = 2.71828... as its base. ln(e) = 1. It's the inverse of eˣ. Natural logs appear everywhere differential calculus is used: radioactive decay (N = N₀e⁻λt), compound interest (A = Pe^(rt)), population growth, and the normal distribution. The relationship between them is: ln(x) = log(x) / log(e) ≈ log(x) / 0.4343, or equivalently ln(x) = 2.303 × log(x).
Key logarithm rules every student should know: log(a×b) = log(a) + log(b). log(a/b) = log(a) − log(b). log(aʸ) = b × log(a). log(1) = 0. log(10) = 1 (base 10), ln(e) = 1 (base e). These rules allow you to break complex expressions into simpler parts — which is why logarithms were used as a computational shortcut before calculators existed.
The four memory buttons replicate the behavior of physical scientific calculators. M+ adds the currently displayed value to memory (e.g., after calculating a subtotal, press M+ to accumulate it). M− subtracts the current value from memory. MR recalls whatever is in memory and inserts it into the current expression — useful for referencing an intermediate result without retyping it. MC clears memory to zero.
Practical workflow: calculate the first sub-expression, press M+. Calculate the second sub-expression, press M+. Then press MR to use the accumulated total. The M badge in the display corner lights up whenever memory holds a non-zero value, preventing the common mistake of forgetting memory is active.
| Key | Action | Key | Action |
|---|---|---|---|
| 0–9 | Append digit | Enter / = | Calculate |
| . (period) | Decimal point | Escape | Clear all (AC) |
| + − * / | Operators | Backspace | Delete last character |
| ( and ) | Parentheses | % | Percent operator |
| ^ or ** | Power / exponent | s | sin( |
| c | cos( | t | tan( |
| l | log( | n | ln( |
| r | √( | p | Insert π |
| e | Insert e | ! | Factorial |