Scientific Calculator

A full keypad calculator for bigger sums: brackets, powers, square roots, trigonometry, and logarithms, worked out safely in your browser. Expressions are checked against a strict list of allowed characters before anything is calculated.

How it works: Type an expression with the keypad and press =. Trig functions (sin, cos, tan) use radians, log is base 10 and ln is the natural log. For safety, the expression is first checked against a strict list of allowed characters and functions, then worked out by a small built-in parser — your input is never run as code.

How the Scientific Calculator Works

A scientific calculator handles the sums that are too big, too fiddly or too full of brackets for mental maths or a basic four-function calculator. It is the tool you reach for with school and college homework, science and engineering estimates, spreadsheet checks, and any formula that mixes powers, roots and trigonometry in one line. Instead of working out a long expression in small pieces and writing down each stage, you build the whole expression on the keypad and get one answer at the end.

The calculator follows the standard maths order of operations. Bracketed parts are worked out first, then powers, then multiplication, division and remainder, and finally addition and subtraction. The function keys — sqrt, sin, cos, tan, log and ln — apply to the number or bracketed expression that follows them. Two things are worth knowing before you start: the trig functions work in radians, not degrees, and the two log keys are different — log is base 10, while ln is the natural logarithm (base e). The keypad also gives you the constants π and e as single taps. The % key on this calculator is not a percentage key: it gives the remainder after a division, so 17 % 5 returns 2.

Safety comes first in how this calculator is built. Before anything is calculated, your expression is checked character by character against a strict list of what is allowed: digits, decimal points, the operators + − × ÷ % and ^, brackets, spaces, and the letters that make up the six approved function names and the constants. Anything outside that list is rejected outright, before any maths happens. Your input is then read piece by piece by a small built-in parser and worked out step by step — it is never run as code on the page. That is why this calculator can safely accept complicated expressions: the worst an odd input can do is produce an error message, never anything harmful.

How to Use This Calculator

Build your expression by tapping the keypad buttons. The display at the top shows everything you have entered so far.
Use the bracket keys to group any part that must be worked out before the rest, just as you would write it on paper.
For a function, tap its key first — sin, cos, tan, sqrt, log or ln — then enter the number or bracketed expression it applies to.
Tap = to see the answer in the display.
Tap ⌫ to delete the last thing you entered, or C to clear the whole expression and start again.

Example

Example 1. Work out (8 + 4) ÷ 3 × 2^2. The brackets come first: 8 + 4 = 12. Next the power: 2^2 = 4. Then the division: 12 ÷ 3 = 4. Finally the multiplication: 4 × 4 = 16. The calculator returns 16.

Example 2. Work out sqrt(81) + log(1000). The square root of 81 is 9. The base-10 log of 1000 is 3, because 10 × 10 × 10 = 1000. Adding them gives 9 + 3 = 12. The calculator returns 12.

Understanding Your Result

The number in the display is the value of your whole expression, worked out exactly in the order the rules of maths require. If the answer surprises you, the cause is almost always a missing bracket: the calculator applies the standard order of operations even when that is not the order you had in mind, so (2 + 3) × 4 gives 20 while 2 + 3 × 4 gives 14. Long answers are shown to full precision rather than rounded to money-style two decimals, which is what you want for science and homework. Dividing by zero has no real answer, so if your expression includes one, check it over — and if the display shows an error instead of a number, the expression itself could not be read, usually because a bracket was left open or a function key was left with nothing after it.

Scientific Calculator FAQs

Do the trig functions use degrees or radians?

They use radians. To work with an angle in degrees, multiply it by π and divide by 180 first — so sin of 30 degrees is entered as sin(30 × π ÷ 180), which gives 0.5.

What does the % key do on this calculator?

It returns the remainder after a division, an operation often called modulo. So 17 % 5 = 2, because 17 divides by 5 three times with 2 left over. For everyday percentages, use the Percentage Calculator instead.

What is the difference between log and ln?

The log key is the base-10 logarithm, common in science scales like pH and decibels. The ln key is the natural logarithm, base e, common in growth, decay and interest formulas.

Why did my expression show an error?

Something in it could not be accepted or read: typically an unclosed bracket, a function with no value after it, or a character outside the allowed list. Clear it with C, rebuild it in smaller pieces, and check each bracket closes.

Is it safe to paste in a long expression?

Yes. Every character is checked against a strict allowed list before any calculating happens, unknown words and symbols are rejected, and your input is never executed as code — a small parser simply reads the numbers and operators.