Scientific Calculator - Trig, Log, Exponents, and Parentheses

A scientific calculator evaluates a full expression: parentheses, exponents, roots, logs, and trigonometric functions, with a defined order of operations. It is not a four-function desk machine that only keeps two registers. On a basic calculator, pressing 2 + 3 × 4 can equal 20 because multiply runs after you already added. On this page, 2 + 3 × 4 = 14, because multiplication binds tighter than addition.

The default example is the first identity students check: sin(30) in degree mode equals 0.5. If the Deg/Rad toggle is on radians, sin(30) is sine of 30 radians and is not 1/2. That single switch is the most common source of “the calculator is broken” reports in trigonometry.

This free online scientific calculator uses a shunting-yard parser written in JavaScript. It never calls eval() or new Function(). After the page loads, it still works offline. Last expression, angle mode, and Ans are stored locally for up to 30 days.

1. Leave Deg on for homework trig, or switch to Rad for calculus.
2. Type an expression or use the keypad. Functions insert with an opening parenthesis: sin(, log(, sqrt(. Close with ).
3. Press = (or Enter) to commit the result into Ans. The display also updates as soon as the expression is complete.
4. C clears the expression. Backspace deletes a character. ± flips the sign of the last number. Copy the display when you need it on a worksheet.

Note: this is IEEE floating-point, not a computer algebra system and not exact fractions. For sequential two-register arithmetic without PEMDAS, use the basic calculator. For a single logarithm in any base, see the log calculator. For a^b with more explanation, see the exponent calculator.

Yes. Parentheses first, then functions, then postfix n! and % (percent means ÷100), then exponents ^ (right-associative), then multiply and divide left to right, then add and subtract left to right. Unary minus is weaker than a power, so −2^2 = −4 (that is −(2^2)), matching ordinary mathematical writing and Python’s -2**2.

Worked expressions:

• 2 + 3 × 4 = 14
• (2 + 3) × 4 = 20
• 2^3^2 = 2^(3^2) = 512, not (2^3)^2 = 64
• sin(30) = 0.5 in Deg
• log(1000) = 3 (common log, base 10)
• ln(e) = 1
• 5! = 120
• 50% = 0.5

Implicit multiplication is inserted between a value and a following value: 2π, 2(3+4), (2)(3), 2sin(30). Functions still require parentheses so sin 30 is rejected instead of guessing.

To square a negative, wrap it: (-2)^2 = 4. A leading minus on an empty line starts a negative constant. Log of a power: log(2^10) is log(1024) ≈ 3.0103, not 10, because log is base 10. ln(e^5) displays as 5 after rounding. 10^log(7) should return 7 or a binary neighbor; display rounding often snaps it to 7, which is for reading, not a proof of exact inverses. Cube roots of negatives are not a dedicated key; (-8)^(1/3) may be NaN in IEEE and will error rather than print −2. Use odd-root algebra on paper or a CAS. 1/2π is (1/2)×π here; write 1/(2π) for the reciprocal of 2π.

In degree mode, a full circle is 360°, and sin(30) = 1/2 = 0.5, cos(60) = 0.5, tan(45) = 1. Inverse trig returns degrees: asin(0.5) = 30. That is what high-school homework almost always wants, so this page defaults to Deg.

In radian mode, a full circle is 2π. sin(π/6) = 0.5, and sin(30) is sine of 30 radians ≈ −0.988. Cosine and tangent follow the same unit. Calculus derivatives of sin and cos assume radians. If a physics formula uses ωt with t in seconds and ω in s⁻¹, those arguments are radians.

There is no automatic unit conversion of a typed number unless you write it: to convert 30° to radians by hand, 30 × π/180. To convert π/6 rad to degrees, (π/6)×180/π = 30. The toggle only changes how sin, cos, tan, asin, acos, and atan interpret their argument or result. log, ln, sqrt, exp, abs, and ^ do not care about Deg/Rad.

Use ^ for powers: 2^8 = 256, 9^0.5 = 3 (same idea as sqrt(9)). e^x can be typed as e^x or exp(x). Scientific literals such as 6.02e23 are numbers, not the constant e. The constant e is the key labeled e (Euler’s number).

log is log₁₀. ln is the natural log. log(100) = 2, ln(1) = 0. Both reject zero and negatives. For an arbitrary base, change-of-base is log(x)/ log(b) (or ln), or use the dedicated log calculator.

n! is integer factorial from 0 through 170. 0! = 1, 5! = 120, 10! = 3,628,800. 171! overflows IEEE double (~1.8×10^308), so it is rejected. Non-integers and negatives are rejected; this is not a gamma-function CAS.

Quadratic equations belong on the quadratic formula calculator. You can still type the discriminant by hand here as sqrt(b^2-4*a*c) with numbers filled in, but that is not a symbolic solver.

% is postfix percent, not remainder (modulo). 200+10% is 200 + 0.1 = 200.1, not “increase 200 by 10%.” For that wording, use the percentage calculator’s increase mode. This keypad % matches expression parsers, not cash-register %.

Results are IEEE-754 doubles, the same numbers JavaScript uses everywhere. sin(30°) is computed as sin(30×π/180). π is not exact, so the raw sine can be 0.49999999999999994 before this page rounds for display to 0.5. That is not a trigonometry bug. It is binary floating-point. Do not treat a display of 0.5 as a proof that the internal cosine of 90° is a clean zero - tan(90) is still rejected when cosine is near zero.

This is not a CAS. It will not simplify √8 to 2√2, will not keep 1/3 as a fraction, and will not solve for x. Exact rational arithmetic belongs on a fraction tool. Huge factorials stop at 170!. Powers that overflow print an error instead of Infinity. Complex results (sqrt(−1), log(−2)) are errors, not i.

Display rounding to twelve significant digits (and snapping values extremely close to integers) is why sin(30) reads 0.5 instead of 0.49999999999999994. Cos(90) may read 0 even though the internal cosine of 90×π/180 is a tiny residue; tan(90) is still blocked when that cosine is near zero. Copying more digits than your data had is a reporting mistake, not extra precision the calculator invented.

Leaving the calculator in radians during degree homework. Writing sin30 without parentheses. Using log when the assignment meant ln (or the reverse). Treating 2^3^2 as 64. Using % as “add a tip.” Expecting exact 1/3. Comparing this page to a two-register basic calculator and calling PEMDAS a bug.

Inverse trig range: asin returns −90° to 90° (or −π/2 to π/2). acos returns 0 to 180° (or 0 to π). The other angle that also has that sine is your job via the unit circle, not this display. tan(90°) is undefined, not “a huge number.”

Chain calculations with Ans instead of retyping a long display. After sin(30) shows 0.5, press = to store Ans, then type 2*Ans for 1. If you edit the expression to something incomplete, the live display waits; Equals will then show an incomplete-expression error rather than silently keeping the old number as if it were new. C clears the line, not Ans. There is no undo beyond Backspace.

Hyperbolic functions (sinh, cosh), polar/rectangular conversions, numerical integrals, and matrix modes are not on this keypad. Complex numbers are not on this keypad. Sexagesimal degrees-minutes-seconds must be converted to decimal degrees first: 30°30′ is 30.5, not 30.30. Binary, hex, and programmer modes belong on other tools. Keep this page for real IEEE expressions with the functions listed above.

Parentheses must match. sin(30 is incomplete. Extra closing parens throw mismatched parentheses. A trailing operator 2+3+ is incomplete until you finish the term. Empty parentheses sin() fail as an incomplete or invalid argument. Those rules are stricter than a handheld that might wait on a blinking cursor, and that strictness is what keeps the parser from guessing.

A basic calculator is the two-register machine on this site: you press operations in sequence. A scientific calculator (this page) is an expression engine with trig, logs, powers, and parentheses. A graphing calculator additionally plots y = f(x) and often stores lists; this page does not plot. A CAS (computer algebra system) keeps symbols and exact forms: √8 stays 2√2, sin(π/6) stays 1/2 as a rational. This page is not a CAS. √8 displays about 2.82842712475. If you need 2√2 on paper, simplify by hand.

Handheld scientifics differ in whether 1/2π is (1/2)π or 1/(2π). Here, implicit multiply is the same precedence as ×, so 1/2π tokenizes as 1 / 2 × π, which is (1/2)×π, not 1/(2π). Write 1/(2π) when that is what you mean. That is an honest parser limit, not a secret. The same trap exists on many physical calculators.

Memory on a pocket scientific is often M+, MR, MC. Here the reusable slot is Ans: the last value committed with Equals, or the last successful evaluation stored after you press =. Type Ans^2 to square it. Clearing the expression does not wipe Ans. There is no second independent memory register.

Period of a 0.25 kg mass on a 100 N/m spring: T = 2π√(m/k). Type 2πsqrt(0.25/100) in Deg or Rad - no trig is involved, so the toggle does not matter. √(0.0025) = 0.05, times 2π ≈ 0.314159 seconds. If you forget the closing parenthesis after 100, the parser reports mismatched parentheses instead of inventing a value.

Horizontal range for a projectile (no air) R = v²sin(2θ)/g. With v = 20 m/s, θ = 30°, g = 9.81, Deg on:20^2*sin(2*30)/9.81. sin(60°) ≈ 0.866025, 400×0.866025/9.81 ≈ 35.3 m. If Rad is on, sin(60) is sine of 60 radians and the range is nonsense. Check the toggle before you blame g.

pH of 2.5×10⁻⁴ M acid (strong, complete): -log(2.5e-4) ≈ 3.602. The unary minus applies to the log, not to the argument. log(-2.5e-4) is rejected (non-positive). First-order half-life estimates that use ln(2)/k are ln(2)/k with k in s⁻¹.

Combinations: C(10,3) = 10! / (3!×7!). Type 10!/(3!*7!) = 120. 171! will not run. Mixing factorial with a decimal 3.5! is rejected. Nested factorials (3!)! = 720, which is 6!, not a special key.

Keyboard when the expression field is not focused: digits,., +, -, * or x for ×, / for ÷, ^, %, parentheses, !, Enter for equals, Escape for clear, Backspace to delete. When the expression box is focused, type normally and use Enter to commit Ans.