How to use the scientific calculator
- 1Pick DEG or RAD at the top of the display if your problem has angles in it. Most school trig problems use degrees.
- 2Tap the keys or type on your keyboard. Functions like sin, log and √ open a parenthesis for you, and the answer appears below the expression as you type.
- 3Press = or Enter. Any parentheses you left open are closed for you, the answer moves into the history list and becomes Ans for your next calculation.
- 4Start the next step with an operator, like × 2, to keep working with the last answer, or type a number to start fresh. Copy the result, or copy a link that opens the calculator with your expression.
Order of operations: PEMDAS
The calculator follows the order of operations taught in American schools, remembered as PEMDAS: Parentheses, Exponents, Multiplication and Division, Addition and Subtraction. Multiplication and division share a level and run left to right, and so do addition and subtraction. That is why 2 + 3 × 4 is 14, not 20, and 10 − 4 − 3 is 3.
A few details matter on a scientific calculator:
- Exponents group from the right. 2^3^2 means 2^(3^2) = 2^9 = 512, not 8² = 64.
- The minus sign comes after the exponent. −3² is −(3²) = −9. Put the minus inside parentheses, (−3)², to square a negative number.
- Factorial, squares and percent bind tightest. 2^3! is 2^6 = 64, and √4! is the square root of 24, about 4.9.
- Implicit multiplication counts like ×. You can write 2π, 3(4 + 5) or 2sin(30) without a × sign. Here it has the same priority as × and ÷, so 6 ÷ 2(1 + 2) is 9 and 1 ÷ 2π is π/2, not 1/(2π). Some handhelds give implicit products a higher priority, which is where the famous viral math arguments come from. If in doubt, add parentheses: 1 ÷ (2π).
- nPr and nCr sit between powers and multiplication, so 2 × 5 nCr 2 is 2 × 10 = 20.
Degrees vs radians
Angles can be measured in degrees, where a full turn is 360°, or in radians, where a full turn is 2π, about 6.283. Gradians, the third option, split a turn into 400 and are mostly used in surveying. The mode only changes the trig functions: in DEG, sin(30) is 0.5, in RAD, sin(30) means the sine of 30 radians, which is about −0.99. Getting a strange trig answer is almost always a sign that the calculator is in the wrong mode.
Use degrees for triangles, slopes, navigation and most geometry homework. Use radians in calculus, physics formulas with ω or θ in them, and anything that mixes angles with π. To convert by hand, multiply degrees by π/180 to get radians, and radians by 180/π to get degrees. The inverse functions sin⁻¹, cos⁻¹ and tan⁻¹ give their answer in the current mode, so tan⁻¹(1) is 45 in DEG and 0.785398163397 (π/4) in RAD.
What the keys do
- sin, cos, tan and the inverses on the 2nd key work with angles. tan(90°) has no value, so it shows a Math error instead of a huge number.
- sinh, cosh, tanh are hyperbolic functions, used in engineering and physics. They ignore the angle mode.
- log is the common logarithm, base 10, and ln is the natural logarithm, base e ≈ 2.718. log₂ is base 2, handy in computer science. For any other base, divide two logs: log base 5 of 125 is log(125) ÷ log(5) = 3.
- x², x³ and xʸ raise to a power, also called an exponent. With 2nd, xʸ becomes the y-th root: type 81 2nd xʸ 4 for the fourth root of 81, which is 3.
- √ and ∛ take the square root and cube root. The cube root of a negative number is real, so ∛(−8) = −2.
- 10ˣ and eˣ undo log and ln. EXP types numbers in scientific notation: 6.02E23 means 6.02 × 10²³. Only a capital E does this; a small e is Euler's number.
- x! is the factorial, 5! = 120. It works for whole numbers up to 170!, the largest that fits.
- nPr and nCr count arrangements and combinations: 5 nCr 2 = 10 ways to choose 2 of 5 when order does not matter.
- mod gives the remainder: 17 mod 5 = 2. With a negative number the answer takes the sign of the divisor, so −7 mod 3 = 2.
- Memory keys: M+ adds the current answer to memory, M− subtracts it, MR puts the stored number into your expression and MC clears it. Ans is the last answer you got with =.
Examples
Each result below was checked against JavaScript's built-in math functions.
| Expression | Result | Why |
|---|---|---|
| 2 + 3 × 4 | 14 | Multiplication before addition |
| (2 + 3) × 4 | 20 | Parentheses first |
| −3² | −9 | The square applies to 3, then the minus |
| (−3)² | 9 | Parentheses make the minus part of the base |
| 2^3^2 | 512 | Powers group from the right: 2^9 |
| 6 ÷ 2(1 + 2) | 9 | Implicit × counts like ×, left to right |
| sin(30) in DEG | 0.5 | Degrees mode |
| sin(1) in RAD | 0.841470984808 | Radians mode |
| tan⁻¹(1) in DEG | 45 | Inverse tangent gives an angle |
| log(1000) | 3 | Log base 10 |
| ln(e²) | 2 | Natural log undoes e to a power |
| log₂(1024) | 10 | Log base 2 |
| √(3² + 4²) | 5 | Hypotenuse of a 3, 4, 5 triangle |
| ∛(−27) | −3 | Odd roots of negative numbers are real |
| 5! | 120 | 5 × 4 × 3 × 2 × 1 |
| 52 nCr 5 | 2,598,960 | Five-card poker hands |
| 10 nPr 3 | 720 | Ordered picks of 3 from 10 |
| 17 mod 5 | 2 | Remainder of 17 ÷ 5 |
| 200 + 15% | 230 | Adds 15% of 200 |
| 6.02E23 × 2 | 1.204 × 10²⁴ | Scientific notation |
| 1 ÷ 3 | 0.333333333333 | Rounded to 12 significant digits |
Keyboard shortcuts
Everything works from the keyboard. Type into the expression field, or just start typing while the calculator is on screen.
| Key | Does |
|---|---|
| 0 to 9, . | Numbers |
| + - * / | Plus, minus, times, divide |
| ^ | Power, so 2^10 is 1,024 |
| ( ) | Parentheses |
| ! % | Factorial, percent |
| sin, cos, tan, asin, ln, log, sqrt, cbrt, abs | Type the name, then the number in parentheses |
| pi, e, Ans, mod, nCr, nPr | Constants and operators by name |
| Enter or = | Calculate |
| Backspace | Delete the last character |
| Esc | Clear the expression |
Common mistakes
- Wrong angle mode. If sin(30) does not give 0.5, you are in RAD. Check the DEG and RAD switch before any trig problem.
- Squaring a negative without parentheses. −5² is −25. Write (−5)² for 25.
- Dividing by a product. a ÷ bc is read as (a ÷ b) × c. Write a ÷ (b × c) when the whole product belongs in the denominator, for example 1 ÷ (2π).
- Fractions in exponents. 8^1/3 is 8¹ ÷ 3. For a cube root write 8^(1/3), or use ∛.
- Mixing up log and ln. log(100) = 2, but ln(100) ≈ 4.605. Formulas from chemistry and decibels use log, growth and decay formulas usually use ln.
- Misreading E notation. 1.5E−9 is 0.0000000015, a very small number, not 1.5 minus 9.
Frequently asked questions
How do I switch between degrees and radians?
Use the DEG, RAD and GRAD switch at the top of the display. It changes how sin, cos and tan read their input and how sin⁻¹, cos⁻¹ and tan⁻¹ report their answer. Your choice is remembered on this device. Logs, roots, powers and the hyperbolic functions are the same in every mode.
Why does −3² give −9 and not 9?
Powers come before the minus sign, so −3² means −(3²) = −9. This matches how math is written and how TI and Casio calculators work. To square negative 3, type (−3)², which gives 9.
What does 6 ÷ 2(1 + 2) equal?
This calculator gives 9. It treats a multiplication without a sign, like 2(1 + 2), the same as one with a × sign, and works left to right: 6 ÷ 2 = 3, then 3 × 3 = 9. Some calculators give implicit multiplication a higher priority and answer 1. Add parentheses, like 6 ÷ (2(1 + 2)), whenever you mean something else.
Can I type with my keyboard?
Yes. Type numbers, + − * / ^ ( ) ! and %, and names like sin, cos, sqrt, ln, log and pi straight into the expression field or anywhere on the page while the calculator is in view. Enter or = calculates, Backspace deletes and Escape clears.
Why does 0.1 + 0.2 show 0.3 here when some apps show 0.30000000000000004?
Computers store numbers in binary, where 0.1 and 0.2 cannot be written exactly, so tiny rounding errors appear. This calculator rounds every answer to 12 significant digits, the way handheld calculators do, so you see 0.3. Very large and very small answers switch to scientific notation.
How does the percent key work?
On its own, 15% is 0.15. After a plus or minus it takes a percent of the number before it, so 200 + 15% = 230 and 200 − 15% = 170, like on a shop calculator. In a product, 50 × 15% = 7.5.
Is my history saved?
Your history lasts while the page is open. Tick "Remember on this device" to keep it in your browser for next time. Nothing is sent to a server, and the Clear button deletes it.