Scientific Calculator

Most scientific calculators, the plastic ones and half the sites online, make you press one key at a time and trust a running total you can't actually see. This one is a line you type. Write the whole calculation out, (2 + 3) × 4 − 1 or sin(45) + log(1000), and the answer works itself out underneath as you go, before you ever touch equals. So you get to read back what you typed, spot the bracket you left open, and fix it right there instead of clearing everything and starting from scratch.

That live line is the reason to reach for this over the calculator already on your phone. It handles the full scientific set in one expression: parentheses, exponents, roots, base-10 and natural logs (and any base you like), the trig and hyperbolic families, factorials, permutations and combinations, plus π and e. Type it, tap the pad, or mix the two. Nothing you enter leaves your browser, and once the page has loaded it keeps working offline.

1. Type or tap an expression. Both work and you can switch mid-calculation. Tap sin(, type 45, tap ), or just type the whole thing.
2. Watch the answer appear as you type. The live preview evaluates whatever you've written so far. While the line is still incomplete, say a bracket left open, it shows Error in red rather than a made-up number, so you never mistake a half-finished line for the result.
3. Hit = or press Enter to lock the result in. Enter does the same job as the = key, and locking in saves the line to your history.
4. Pick DEG, RAD, or GRAD (top right) before any trig. This decides whether sin(90) reads as degrees or radians, and getting it wrong throws off every angle.
5. Tap 2nd for the inverse and second functions. sin becomes sin⁻¹, √ becomes ∛, x² becomes x³, ln becomes eˣ, log becomes 10ˣ. Tap it again to flip back.
6. Hold a number aside with the memory keys. MS stores, MR recalls, M+ and M− add or subtract the live value, MC clears. A small M badge shows when something is stored.
7. Reuse the last result with Ans, and reload any earlier calculation from the history list with its Use button.

A cheap calculator computes as you press, so by the time you notice you fat-fingered a digit three keys ago, the running total is already wrong and there's no way to see where. Here the full expression sits in front of you the whole time. 2 × (14 + 6) ÷ 5 is right there as text. You proofread it like a sentence, and the answer underneath updates with every keystroke, so a typo usually shows up as a number that's obviously off before you commit.

A few things make typing faster than tapping. You can drop the multiplication sign where you'd skip it by hand, 2π reads as 2 × π and 2(3) reads as 2 × 3. The Ans key pulls in your last result, so after √500 you can start the next line with Ans × 2 instead of copying out a long decimal.

Two features other calculators skip entirely. The Share link packs your exact expression into a URL, so you can send a colleague nCr(52, 5) already loaded and ready, not a screenshot they have to retype. And your history stays on the device, twelve lines deep, each one a button that reloads the expression so you can tweak one number and rerun. Both live on your machine, nothing syncs anywhere.

The single reason a real scientific calculator beats a four-function one is that it reads the entire expression before answering. Type 2 + 3 × 4 and you get 14, because multiplication runs before addition (the PEMDAS order: parentheses, then exponents, then multiply and divide, then add and subtract). A press-as-you-go pocket calculator adds first and hands you 20, confidently wrong. This one reads the whole line and applies the rule.

Parentheses are how you override that order when you need to. (2 + 3) × 4 is 20, because the bracket forces the addition first. They matter most with roots and functions. √(9 + 16) takes the root of 25 and gives 5, while √9 + 16 roots only the 9 and lands on 19. When you're unsure, add a bracket, an extra pair that just confirms your intent costs nothing.

One gotcha worth knowing, because textbooks themselves disagree on it. -2^2 here is -(2^2), which is -4, since the exponent binds tighter than a leading minus. If you meant the negative squared, write (-2)^2 and you'll get 4. The parentheses remove all doubt, that's what they're for.

If a sine or cosine comes back looking nothing like you expected, check the DEG/RAD/GRAD toggle first. It's almost always the culprit. In degree mode sin(90) is 1. In radian mode the same sin(90) treats 90 as radians, a huge angle spun many times around the circle, and returns about 0.894. Neither is a bug, the calculator is doing exactly what the toggle told it. Rule of thumb, if there's a π in the angle you want radians, otherwise degrees. The inverse trig on the 2nd layer respects the same setting.

The 2nd column shows what a key becomes once you tap 2nd.

Key	Does	With 2nd
sin cos tan	Trig, in your DEG/RAD/GRAD unit	sin⁻¹ cos⁻¹ tan⁻¹
sinh cosh tanh	Hyperbolic (no angle unit)	inverse hyperbolic
ln / log	Natural log / base-10 log, log(x, b) for any base	eˣ / 10ˣ
x² / √	Square / square root	x³ / ∛ cube root
xʸ	Any power, 2^10 is 1024	ⁿ√, written root(x, n)
x!	Factorial, 5! is 120
nCr nPr	Combinations and permutations
EE	Scientific notation, 3 EE 8 is 3 × 10⁸

A couple of rules the tool holds you to. You can't take an even root of a negative and get a real answer, so √-4 shows Error, though an odd root like ∛-27 is a real -3. Factorials only take whole numbers zero or above, and logs need a positive input. When something can't be computed the display says Error rather than inventing a number.