Full-featured scientific calculator with trig functions, logarithms, powers, roots, scientific notation, and a built-in constants library. 2nd mode for inverse functions, persistent history, and full keyboard support. Works on any device — perfect for GCSE and A-Level maths revision.
Tip: Use your keyboard for faster input. Press ? for shortcuts.
Mathematical rules & formulas
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A scientific calculator is an advanced calculator that goes beyond basic arithmetic (+, -, ×, ÷). It handles trigonometric functions (sin, cos, tan), logarithms (log, ln), powers and roots (x², √, xʸ), factorials (n!), and scientific notation (×10ⁿ).
In the UK education system, scientific calculators are essential from GCSE onwards. Physical calculators like the Casio fx-83GT or fx-991EX are used in exams, but this free online version is perfect for homework, revision, and learning how the functions work before your exam.
Our calculator replicates all the functionality of a physical scientific calculator, plus extras like a constants library (physics, chemistry, maths), persistent history, and a reference sidebar with key formulas.
sin, cos, tan and their inverses (sin⁻¹, cos⁻¹, tan⁻¹). Toggle between degrees and radians. Hyperbolic functions via the settings panel.
Common log (base 10), natural log (ln), and their inverses (10ˣ, eˣ) in 2nd mode. Understand the difference between log and ln.
Square (x²), cube (x³), any power (xʸ), square root (√), cube root (³√), reciprocal (x⁻¹), and factorial (n!). Permutations and combinations in 2nd mode.
Store values with M+/M−, recall with MR, clear with MC. Full calculation history saved to your browser — persists across sessions.
One-click access to physics constants (c, g, G, h, k_B, N_A), chemistry constants (R, F), and maths constants (π, e, φ, √2).
Press 2nd to access inverse and alternate functions — just like the SHIFT button on a real Casio calculator. Auto-deactivates after one press.
Trigonometric functions relate angles to ratios of sides in a right-angled triangle. On the unit circle (radius = 1), sin(θ) gives the y-coordinate and cos(θ) gives the x-coordinate at angle θ.
| Angle | sin | cos | tan |
|---|---|---|---|
| 0° | 0 | 1 | 0 |
| 30° | 1/2 | √3/2 | 1/√3 |
| 45° | √2/2 | √2/2 | 1 |
| 60° | √3/2 | 1/2 | √3 |
| 90° | 1 | 0 | — |
Tip: Use DEG mode for these values. In RAD mode, 90° = π/2, 45° = π/4, etc.
Pythagorean
sin²θ + cos²θ = 1
Tangent
tanθ = sinθ / cosθ
Double angle (sin)
sin(2θ) = 2sinθcosθ
Double angle (cos)
cos(2θ) = cos²θ - sin²θ
Reciprocal
secθ = 1/cosθ, cscθ = 1/sinθ
DEG ↔ RAD
180° = π rad
Converting DEG ↔ RAD: Multiply by π/180 to go from degrees to radians. Multiply by 180/π to go from radians to degrees. Example: 60° = 60 × π/180 = π/3 radians.
A logarithm answers the question: “What power do I raise the base to in order to get this number?” If loga(b) = c, that means ac = b.
| Feature | log | ln |
|---|---|---|
| Full name | Common logarithm | Natural logarithm |
| Base | 10 | e ≈ 2.718 |
| Notation | log₁₀(x) or log(x) | logₑ(x) or ln(x) |
| log(100) | 2 (since 10² = 100) | 4.605 |
| Main use | Orders of magnitude, pH | Calculus, growth/decay |
Multiplication
xᵃ · xᵇ = xᵃ⁺ᵇ
e.g. x³ · x² = x⁵
Division
xᵃ / xᵇ = xᵃ⁻ᵇ
e.g. x⁵ / x² = x³
Power of Power
(xᵃ)ᵇ = xᵃᵇ
e.g. (x²)³ = x⁶
Zero Power
x⁰ = 1
e.g. 7⁰ = 1
Negative Power
x⁻ⁿ = 1/xⁿ
e.g. 2⁻³ = 1/8
Fractional Power
x^(1/n) = ⁿ√x
e.g. 8^(1/3) = 2
Scientific notation expresses numbers as a × 10ⁿ, where 1 ≤ a < 10. It makes very large or very small numbers easier to read and work with.
How to enter with the EXP button:
Large numbers: Move the decimal left until you have a number between 1 and 10. Count the moves — that's the exponent.
299,792,458 → 2.998 × 10⁸ (moved 8 places left)
Small numbers: Move the decimal right. The exponent is negative.
0.00000166 → 1.66 × 10⁻⁶ (moved 6 places right)
The order of operations determines which part of a calculation is evaluated first. Without it, the same expression could give different answers. Our calculator follows the standard mathematical order automatically.
Evaluate everything inside brackets first
Powers, roots, and scientific notation
Left to right, equal priority
Left to right, equal priority
2 + 3 × 4
= 2 + 12
= 14
Multiplication before addition (NOT 5 × 4 = 20)
(2 + 3) × 4
= 5 × 4
= 20
Brackets force addition first
2³ + 4 × 3
= 8 + 12
= 20
Exponent first, then multiplication, then addition
24 ÷ 6 × 2
= 4 × 2
= 8
÷ and × have equal priority — evaluate left to right
Common mistake: Evaluating 2 + 3 × 4 as 20 instead of 14. Multiplication always happens before addition unless brackets override it.
| Key | Action |
|---|---|
| 0-9, . | Enter numbers and decimal point |
| + - * / | Basic arithmetic operators |
| ( ) | Parentheses for grouping |
| ^ | Power (exponent) |
| % | Percentage / modulo |
| ! | Factorial |
| p | Insert π (pi) |
| e | Insert e (Euler's number) |
| Enter / = | Calculate result |
| Backspace | Smart delete (removes whole tokens) |
| Escape | Clear all |
| ? | Show keyboard shortcuts modal |
Before trig calculations, confirm the angle mode matches the question. Most GCSE/A-Level questions use degrees. Calculus often uses radians.
When in doubt, add parentheses. sin(30) is unambiguous, but sin30+5 could be misinterpreted. More brackets = fewer errors.
If sin(30°) = 0.5, verify by checking sin⁻¹(0.5) = 30°. This catches mode errors and typos.
For multi-step calculations, store intermediate values with M+ and recall with MR. This avoids rounding errors from retyping.
In physics and chemistry, answers often need to be in standard form (a × 10ⁿ). Use the EXP button to enter and verify these.
The button layout here mirrors a real Casio scientific calculator. Practice here to build muscle memory, then apply it to your physical calculator in the exam.
Trig (sin, cos, tan and inverses), hyperbolic (sinh, cosh, tanh), log (base 10), ln (natural), powers (x², x³, xʸ), roots (√, ³√), factorial (n!), permutations (nPr), combinations (nCr), scientific notation (EXP), memory functions, and a library of physics, chemistry, and maths constants.
Yes! Click the DEG/RAD button (top of keypad). DEG mode is default and used for most exam questions. RAD mode is for calculus and university maths.
Absolutely. The calculator is fully responsive with touch-friendly buttons (44px+ touch targets). No app download needed — it runs entirely in your browser.
Yes — history is saved to your browser's local storage and persists across sessions. Click the History button to view, search, and reuse past calculations. No data is sent to any server.
Check your angle mode. In DEG mode, sin(90) = 1. In RAD mode, sin(90) ≈ 0.894 because 90 radians is a completely different angle from 90°. Switch to DEG mode for degree-based calculations.
Type 2, then press the xʸ button (or type ^), then type 5, then press =. The answer is 32. For squares and cubes, you can also use the dedicated x² and x³ buttons.
Type the coefficient, press the EXP button (×10ˣ), then type the exponent. For example, for 6.022 × 10²³, type: 6.022, EXP, 23. For negative exponents like 1.6 × 10⁻¹⁹, type: 1.6, EXP, -, 19.
log is the common logarithm (base 10): log(100) = 2 because 10² = 100. ln is the natural logarithm (base e ≈ 2.718): ln(e) = 1. In A-Level maths and calculus, ln is used far more frequently.
Press the 2nd button to activate inverse mode. The n! button becomes nPr and the % button becomes nCr. Enter n, press the function, enter r. Example: 5P3 = 60, 5C3 = 10.
Click the Constants button (⚛) to access: speed of light (c), gravitational acceleration (g), Planck constant (h), Boltzmann constant (k_B), elementary charge (e), Avogadro constant (N_A), vacuum permittivity (ε₀), gas constant (R), Faraday constant (F), and more. Click any constant to insert its value.
The 2nd button (orange, top-left) toggles inverse mode. Function buttons change: sin → sin⁻¹, cos → cos⁻¹, tan → tan⁻¹, log → 10ˣ, ln → eˣ, √ → ³√, x² → x⁻¹. It auto-deactivates after one function press, just like a real Casio.
This calculator covers all functions needed for GCSE and A-Level maths: trig, logs, powers, roots, factorials, nPr, nCr, and scientific notation. It's perfect for revision and homework. Note: you cannot use an online calculator in actual exams — use a physical Casio fx-991EX and practice here to learn the buttons.
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