Scientific Calculator
An online scientific calculator you write expressions into instead of tapping key by key: trig in degrees or radians, logs, powers, factorials, and exact answers like 2/3 + 3/4 = 1 5/12.
Result
The expression does not parse.
No real value.
The same expression in each unit
Type it, or build it from the keys below. There is no equals key — press Enter to fold the answer back in.
Angle unit
Degrees on load. It rides the URL, so a shared link opens in the same unit — and it is remembered for your next visit.
Result form
The track appears only when the answer genuinely is a fraction.
Functions
Keys
How to use
- Write the expression into the box at the top, or assemble it from the function keys and the number pad.
- Choose Degrees or Radians before anything trigonometric goes in. Degrees is what you get on load.
- Watch the result update as you type, and press Enter when you want the answer folded back into the box to build on.
- If the Result form track appears, use it to pick Decimal, Mixed or Improper; all three stay listed below, and Copy the answer takes the one on show.
What it handles
You write here rather than tap. It's a scientific calculator built around one expression box: put in sin(45) + sqrt(2) * pi the way you'd write it on paper and 5.14998971934 appears as the result while you type. No equals key exists. Press Enter and the answer takes the place of what you typed, which saves retyping when the next step starts from this one.
Fractions stay exact. Type 1/2 + 1/3 and 5/6 comes back reduced, with no rounding to worry about. Mixed numbers go in directly, so 1 1/2 + 2 3/4 is understood and answers 4 1/4. A Result form track picks Decimal, Mixed or Improper, and it only turns up when the answer genuinely is a fraction, so asking for sqrt(2) gives a decimal and nothing to flip.
The function pad carries sin, cos and tan with all three inverses, log for base 10 and ln for natural, plus sqrt, abs, exp, π, e and a factorial key. Powers use ^ and associate to the right, which makes 2^3^2 equal 512 rather than 64. Implicit multiplication is accepted, so 2pi and 3(4+1) behave. Unary minus binds looser than the power, meaning -2^2 comes out as -4.
Answers print to twelve significant figures, and a number past twelve digits switches to exponent form rather than padding with zeros, so 2^64 reads 1.84467440737e+19. Sine and cosine land on a clean 0 at their zeros, so sin(180) in degrees gives 0 rather than the 1.2246e-16 floating point produces, while a number you type stays as typed: 1e-13 is 1e-13. Degrees is the mode on load, the Angle unit track switches to radians and remembers your choice, and asin, acos and atan hand their answers back in whichever unit is selected.
Keypad presses land at the cursor rather than the end of the line, and after a digit the e key inserts ×e so 2, e, +, 1 means 2e + 1 rather than 2e+1 in scientific notation. Click into the middle of a long expression and the bracket you press drops exactly where it belongs. ⌫ removes one character or whatever you've highlighted, AC empties the box. Behind all of it sits a hand-written tokenizer and parser rather than JavaScript's eval, which is why a stray character comes back as a message naming the position it sits at. The expression and the angle mode both ride in the URL, so a link carries the whole calculation with it.
Watching the fraction drop out
Type 2/3 + 3/4. The result reads 1.41666666667, the same number is listed three ways underneath (1.41666666667, 1 5/12 and 17/12), and a Result form track turns up beside the angle unit. Pick Mixed and 1 5/12 becomes the result, and the copy button takes that form.
Now extend it to 2/3 + 3/4 + sqrt(2). The track vanishes and you're left with 2.83088022904 on its own. Nothing broke: the root of two is irrational, so there is no exact fraction to offer any more.
Good to know
- Exactness has a boundary. An answer stays a fraction only while every piece is a whole number or fraction joined by + − × ÷ or raised to a whole power up to 64. Bring in sqrt, a trig function, π or e and you get a decimal, because those values have no fractional form to give.
Frequently asked questions
How do I add two fractions and get a fraction back?
Write it the obvious way. 1/2 + 1/3 gives 5/6, 3/4 * 2/3 gives 1/2, and 2/4 comes back reduced to 1/2. Whole numbers, fractions, brackets and whole-number powers all keep the answer exact, and the result is reduced before you see it.
How do I turn a decimal into a fraction?
Type the decimal on its own. Entering 0.75 lists the fraction 3/4 under it, and 0.1 + 0.2 comes back as a clean 0.3 with 3/10 alongside rather than the 0.30000000000000004 that raw floating point would hand you. The Result form track picks which one leads.
Where do I switch it to radians?
The Angle unit track sits beside the expression box. In degrees sin(30) is 0.5; in radians the same 0.5 comes from sin(pi/6). The choice is remembered for your next visit, and it also rides the page URL, so a link you paste opens in the same unit without changing what you saved.
Which functions and constants can I use?
sin, cos, tan, asin, acos, atan, log for base ten, ln for natural log, sqrt, abs and exp. Constants are pi (or π) and e. Operators are + − * / ^ and the postfix !, and every function needs its argument in brackets, as in log(1000) or sqrt(16). Names are case-insensitive, so SIN(30) is fine.
How do I do a cube root, or a fifth root?
Raise to a fractional power and keep the fraction in brackets. 27^(1/3) gives 3 and 32^(1/5) gives 2. Without the brackets you'd be dividing after the power, which is a different sum. Square roots have sqrt() as a shortcut.
Does 2(3+1) work without a multiplication sign?
Yes, a number sitting directly against a bracket, a constant or a function is read as multiplication. So 2(3+1) is 8, 2pi is 6.28318530718, and (1+1)(2+2) is 8. Write the × when you want to be sure of what you meant.
Why is my answer showing Undefined or ∞?
Undefined means the expression has no real value, which covers sqrt(-1), log(-5), asin(2) and tan(90) in degrees, since everything here is computed over real numbers; a note says why. The ∞ symbol turns up only when a result overflows, so 171! shows it because 170! is the largest factorial a double can hold. Division by zero is refused with a message instead, whether it is 1/0 or pi/0.
Can it solve an equation for x?
It cannot. There are no variables, no memory registers and no solver; each expression is evaluated on its own and forgotten. For rearranging equations you want algebra software rather than a calculator like this one.
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