Check DEG or RAD before any trig problem
Most wrong answers on a scientific calculator come from the angle mode, not the arithmetic. This calculator opens in degrees, shown as DEG in the top left corner of the screen. Press the DEG key to flip to RAD. The setting sticks for your next visit.
Here is the same input in both modes. If sin(30) gives you −0.988, you are in radians.
| You type | DEG result | RAD result |
|---|---|---|
| sin(30) | 0.5 | -0.98803162409286 |
| cos(60) | 0.5 | -0.95241298041516 |
| tan(45) | 1 | 1.6197751905439 |
| asin(0.5) | 30 | 0.5235987755983 |
Use degrees for school geometry, ramps, roof pitch, surveying, or any angle measured with a protractor. Use radians for calculus, angular velocity, wave equations, or any formula where π appears inside the angle, such as sin(π/6).
What each key puts on the screen
Every key types text into the expression. Nothing runs until you press =, so you see the whole sum before solving. The grey line under the expression shows a live answer while you type. Press 2nd to swap the labels on the blue keys, use one of the swapped functions, and 2nd switches itself off again.
| Key | Types | Try | Answer |
|---|---|---|---|
| sin cos tan | sin( | sin(30) | 0.5 |
| sin-1 and friends | asin( | asin(0.5) | 30 |
| ln | ln( | ln(e^2) | 2 |
| log | log( | log(1000) | 3 |
| ex 10x | e^( 10^( | 10^(3) | 1000 |
| x2 xy | ^2 ^ | 2^10 | 1024 |
| y√x | ^(1/ | 27^(1/3) | 3 |
| √ ∛ | √( ∛( | √(2) | 1.4142135623731 |
| n! | ! | 6! | 720 |
| 1/x | ^(−1) | 8^(−1) | 0.125 |
| EXP | E | 6.02E23×2 | 1.204E24 |
| % | % | 200×15% | 30 |
| Ans | Ans | Ans×2 | Doubles the last answer |
The memory keys hold one number between calculations. M+ adds the current answer to memory, M− subtracts the answer, MR types the stored value, and MC empties memory. An M appears on the screen while memory holds a value. Memory resets when you close the tab.
Keyboard typing accepts a few extras with no key of their own: sinh, cosh, tanh, exp, pi, plus * and / as stand-ins for × and ÷.
How the calculator reads a long expression
Operations run in this order, from first to last:
- Brackets. A bracket left open at the end gets closed for you, so
sin(30solves to 0.5. - Factorial and percent, applied to the number right before them.
- Powers, read right to left.
2^3^2means 29, which is 512, not 64. - A minus sign in front of a number, after powers.
−2^2gives −4. Type(−2)^2for 4. - Multiplication and division, left to right.
- Addition and subtraction, left to right.
You skip the × sign whenever the meaning is clear. 2π, 3(4+1) and 4sin(30) all multiply. Implied multiplication ranks the same as ×, so 6÷2(1+2) returns 9. Some handheld models give implied multiplication priority and return 1 for the same keys. When a textbook answer disagrees with yours, add brackets to say what you mean: 6÷(2(1+2)).
Four problems solved on this calculator
Ramp angle
A ramp rises 1.2 m along a 4 m sloped board. The angle is the inverse sine of rise over length. In DEG mode, type asin(1.2/4).
17.46°. The usual accessibility limit is a 1:12 slope, atan(1/12) = 4.76°, so this board is far too steep for a wheelchair.
Savings growth
$5,000 earns 6% a year, compounded monthly, for 10 years. Type 5000×(1+0.06/12)^120.
$9,096.98. Change 120 to 240 for twenty years.
pH of a solution
The hydrogen ion concentration is 3.2 × 10-4 mol/L. pH is the negative base-10 log. Type −log(3.2E−4) using the EXP key for E.
pH 3.49, about as acidic as orange juice.
Carbon dating
A sample keeps 30% of its carbon-14. With a half-life of 5,730 years, age is 5730 × ln(0.3) ÷ ln(0.5). Type 5730×ln(0.3)/ln(0.5).
About 9,953 years old.
Where this calculator stops
- About 15 digits of precision. Numbers are stored as 64-bit floating point, the same format as a spreadsheet. The screen rounds to 14 digits, which is why 0.1+0.2 shows 0.3 instead of 0.30000000000000004. Exact whole numbers past 9,007,199,254,740,992 lose their last digits.
- Factorials stop at 170! The answer, 7.257E306, sits near the largest number the format holds. 171! returns an error. Decimals such as 2.5! also return an error, since the gamma function is not built in.
- No complex numbers. √(−4) returns an error, not 2i. The square root calculator gives the imaginary form. Odd roots of negatives work:
∛(−27)and(−8)^(1/3)both give the real answer. - Percent divides by 100, nothing more.
50+10%gives 50.1, not the 55 a shop till shows. For a 10% markup, type50×1.1. - tan(90°) is undefined and shows an error. In RAD mode, tan(π/2) returns 1.633E16 instead, because π is stored to 15 digits, not exactly.
- No graphs, no algebra. To plot y = sin(x) use the function grapher. To simplify or expand an expression containing x, use the algebraic expression calculator.
History lives in this browser only, capped at 25 entries. Nothing you type goes to a server.