An online scientific calculator for trig, logarithms, powers, roots, factorials and constants, with degree/radian mode and correct order of operations. No download or sign-up.
Free online scientific calculator. Supports + − × ÷, powers, roots, π, e, trigonometry (degrees or radians), logarithms, factorials and parentheses.
Should My Calculator Be in Degrees or Radians?
Use degrees when your angles are in degrees and radians when they’re in radians. Check the mode button above the keypad, DEG or RAD, before any trig. Get it wrong and the answer changes completely: sin(30) is 0.5 in degrees but about −0.988 in radians.
| Input | DEG mode | RAD mode |
|---|---|---|
| sin(30) | 0.5 | ≈ −0.988 |
| cos(60) | 0.5 | ≈ −0.952 |
| tan(45) | 1 | ≈ 1.620 |
| sin(90) | 1 | ≈ 0.894 |
So sin 30 in radians is about −0.988, while 30 degrees converted to radians is π/6 (about 0.5236), whose sine is 0.5. Use the bracket keys to control the order of operations.
How the Calculator Works
It works like a physical scientific calculator: you build an expression by tapping number, operator and function buttons, and it evaluates the whole thing when you press equals. A math engine reads your expression, applies the order of operations, and resolves every function and constant you’ve inserted.
Formula: The calculator tokenizes the expression you build (numbers, + − × ÷, parentheses, and functions like sin, cos, tan, ln, log, √, x^y, x², x!, %, π, e), converts it to a strict order-of-operations sequence, then evaluates it step by step: parentheses first, then functions and exponents, then × ÷, then + −. Trig functions are computed as sin(x × π/180) when in DEG mode or sin(x) directly in RAD mode. “log” returns log base 10 (Math.log(x)/Math.log(10)), “ln” returns the natural log, “x!” multiplies 1×2×3×…×n for whole numbers from 0 to 170, and “%” divides the current value by 100.
- Set the mode: tap DEG/RAD until it shows DEG.
- Enter the expression: sin(30).
- Press equals: the result is 0.5.
- Expression: the digits, operators and parentheses you build with the button grid, shown live above the answer
- Mode (DEG/RAD): the toggle that decides whether sin, cos and tan treat numbers as degrees or radians
- Function buttons: sin, cos, tan, ln, log, √, x^y, x², x!, % and the constants π and e, inserted at the cursor
- Ans: recalls the result of your previous calculation so you can chain it into a new expression
Using Log, Factorial and the Previous Answer
To use log on this calculator, press log for base 10 or ln for base e. To do a factorial, type a whole number and press x!. To use the previous answer, press Ans. The examples below show each one.
| Expression | Mode | Result |
|---|---|---|
| sqrt(144) | Either | 12 |
| 2^10 | Either | 1024 |
| sin(30) | DEG | 0.5 |
| cos(60) | DEG | 0.5 |
| 5! | Either | 120 |
| log(1000) | Either | 3 |
Common slips and how to avoid them
Most wrong answers come from settings and brackets, not from the arithmetic.
- Check the angle mode before any trig, as the table above shows.
- Bracket generously. 1/2x can be read as 1/(2x) or (1/2)x; typing the brackets removes the doubt.
- Negative powers. -3^2 follows order of operations and gives -9; write (-3)^2 to square the negative number.
- Log bases. log usually means base 10 and ln means base e, and mixing them is a frequent slip in chemistry and finance problems.
Very large results switch to scientific notation, so 6.02e23 means 6.02 × 10^23. Factorials grow fast, and big inputs eventually overflow, a limit of floating-point numbers rather than a fault in the tool. Use Ans to chain steps instead of retyping rounded intermediate values, which adds error. An online calculator is handy for practice, but check which models your exam allows. The order of operations article on Wikipedia explains the precedence rules it follows.
Common questions about using a scientific calculator
Should my calculator be in degrees or radians?
Match the mode to the units of your angle. If the problem gives angles in degrees (30°, 45°, 90°), use DEG; if it uses radians (π/6, 1.2 rad) or calculus, use RAD.What is sin 30 in radians?
If 30 is in radians, sin(30) is about -0.988. If you meant 30 degrees, that’s π/6 radians (about 0.5236), and sin is exactly 0.5.How do I switch between degrees and radians?
Tap the mode button labeled DEG above the button grid; it toggles to RAD and back. This only changes how sin, cos and tan (and their inverses) read numbers, not powers or logs.How do you use log on a calculator?
Press log for base 10, so log(1000) gives 3, or ln for the natural log (base e), so ln(e) gives 1. Use whichever base your problem calls for.How do you do a factorial on this calculator?
Enter a whole number and press x!, so 5! gives 120. It works from 0 to 170; negatives, decimals like 4.5 or anything above 170 return NaN.How do I use the previous answer?
Press Ans to insert the result of your last calculation into the expression, so you can build on it, for example Ans × 2 to double it.Related Calculators
Need to solve for x instead of just evaluating an expression? Try the quadratic formula calculator for equations in the form ax² + bx + c = 0, or the exponent calculator and square root calculator when you just need a quick power or root without building a full expression.