A calculator you can use without fighting the interface. CalcLab’s Everyday calculator has two modes — Simple for quick arithmetic, and Scientific when you need parentheses, powers, roots, logs or trigonometry — and it keeps the same clear display and keyboard shortcuts in both.
This is deliberately a keypad tool, not a domain specialist. When you need UK heating sizes, NICE BMI thresholds or HMRC VAT rules, use the dedicated CalcLab calculators linked from the Everyday hub. Here the job is: type an expression, get a trustworthy IEEE-754 result, move on.
Simple mode — everyday arithmetic
Simple mode covers the keys most people reach for every day: digits, decimal point, the four operations, equals, clear, backspace, plus/minus, percent and square root.
Enter values in the order you think about them. Press = (or Enter on a keyboard) when you want the answer. After a successful equals, the result stays on the display so you can immediately hit +, −, × or ÷ and keep going — classic chaining without retyping the last answer.
AC (or Esc) wipes the expression. ⌫ (Backspace) deletes one character at a time, which is useful when you mistype a long number rather than starting again.
Order of operations
The engine does not evaluate strictly left-to-right. It follows the usual mathematical precedence:
- Powers (
^/ xʸ) - Multiply and divide (
×÷) - Add and subtract (
+−)
So 2+3×4 is 14, not 20. If you want the addition first, switch to Scientific mode and write (2+3)×4.
Percent (%) is postfix: 50% becomes 0.5. Square root is entered as a function — the √ key inserts √( so you finish with a closing parenthesis in Scientific, or complete sqrt(…) from the keyboard.
Scientific mode
Scientific mode adds the tools you’d expect on a pocket scientific calculator:
- Parentheses for grouping
sin,cos,tanand their inverses (asin,acos,atan)- Common log (
log, base 10) and natural log (ln) - Power (
xʸ), square (x²) and reciprocal (1/x) - Constants π and e
Functions insert with an opening parenthesis — for example sin( — so you type the argument and close with ). You can nest: sin(30)+cos(60) in degrees should give 1.
Degrees vs radians
Trigonometry needs an angle unit. The Deg / Rad toggle (remembered in your browser) applies to sin, cos, tan and to the inverse functions’ outputs.
School and most UK everyday problems use degrees: sin(30) = 0.5. Radians matter when you’re following a formula or programming convention that assumes π radians = 180°. If a trig answer looks wildly wrong, check Deg/Rad first — that mismatch is the usual culprit, not the arithmetic.
Keyboard
When the page is focused you can drive the pad from the keyboard: digits and ., + − * /, ^ ( ) %, Enter or = for equals, Esc for AC, Backspace to delete. On a keyboard, * and / map to multiply and divide.
What this calculator is not
It is not a graphing calculator (that’s planned later), not a computer-algebra system, and not a substitute for CalcLab’s domain tools. Floating-point maths can surprise you on pathological inputs — very large powers, near-singular divisions, and awkward irrationals. For money you care about to the penny, prefer the VAT toolkit; for body metrics, prefer the NICE BMI and calorie-deficit planners.
Getting a reliable answer
- Prefer parentheses when the order of operations isn’t obvious.
- Set Deg before classroom-style trig; set Rad for π-based formulas.
- Use AC if the display looks stuck after an error — divide-by-zero and domain errors (like
√(−1)orlog(0)) show a clear message instead of a fake number. - Chain from a result only after a successful equals; starting a new number after equals replaces the previous answer, which matches how physical pads behave.
Use Simple for shopping-bag arithmetic and Scientific when the expression needs structure. When the question is really “what size boiler?” or “what’s my VAT on CIS work?”, leave the keypad and open the specialist calculator — that’s what CalcLab is for.