Scientific Calculator: Online, with Deg/Rad, Memory and History
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How this works
Type an expression the way you would write it and the answer previews as you go; press = (or Enter) to keep it. The calculator follows the usual order of operations: brackets, then powers and roots, then × and ÷, then + and −. Like a Casio, multiplication without a sign binds tighter, so 1÷2π means 1 ÷ (2π), and −3² is −9. Missing closing brackets at the end are added for you.
Trigonometry works in degrees (DEG, the default for O-Level) or radians (RAD). Standard angles come out exact, so sin 30° is 0.5 and cos 90° is 0, with no stray 6.1×10⁻¹⁷. The 2nd key switches to inverse trig, eˣ, 10ˣ, x³, x⁻¹, cube root, nPr and nCr. % divides by 100, EXP enters powers of ten (1.5 EXP 3 is 1,500), and Ans recalls the last answer.
Arithmetic uses IEEE 754 double precision (about 15 to 17 significant digits). Results are shown to 12 significant digits, which hides binary rounding noise (0.1 + 0.2 shows 0.3), and switch to scientific notation from 10¹² and below 0.0001. Expressions are parsed by the calculator's own parser rather than run as code, and nothing leaves your browser.
FAQs
Should I use degrees or radians?
Degrees for most O-Level and N-Level questions, where angles are given in °. Use radians for A-Level H2 Maths calculus and anything with π in the angle; sin(π ÷ 6) in radians is 0.5, the same as sin 30° in degrees.
How do I work out nCr, such as 10C3?
Type 10, press 2nd then nCr, type 3 and press =. 10C3 is 120: the number of ways to choose 3 items from 10 when order doesn't matter. nPr counts ordered arrangements: 10P3 is 720.
Why is −3² equal to −9 and not 9?
Powers are worked out before the minus sign, so −3² is −(3²) = −9. Put the number in brackets to square a negative: (−3)² = 9.
Can I use an online calculator in the O-Level or A-Level exam?
No. Only physical calculators on SEAB's approved list are allowed in national exams, such as the Casio fx-97SG X and fx-97SG CW. Check your model with the SEAB Approved Calculator Checker.