Scientific calculator

A 5 m ladder leans against a wall at 65° to the ground. How high up the wall does it reach?

1. The height is opposite the 65° angle and the ladder is the hypotenuse, so use sin.
2. Height = 5 × sin(65°), with the calculator in degrees.
3. 5 × 0.9063 = 4.53.

Answer: About 4.53 m up the wall.

• Working in radians when the angle is in degrees: sin(30) in radians is −0.988, not 0.5.
• Squaring a negative number without brackets: −3² is −9, while (−3)² is 9.
• Dividing by a product without brackets: 12 / 2 × 3 is 18. Write 12 / (2 × 3) to get 2.
• Rounding halfway through: keep the full value and round only the final answer.

This scientific calculator covers what a school calculator does: trigonometry in degrees or radians, logarithms, powers, roots, factorials and scientific notation. Type a whole expression the way you would write it, or tap the on-screen keys. When the answer is a simple fraction, it shows that too, and your last 30 calculations stay in a history list you can click to reuse.

1. Type an expression in the box, such as 2sin(30) + 3^2, or build it with the on-screen keys.
2. Set Degrees or Radians before using sin, cos or tan. The switch also applies to the inverse functions sin⁻¹, cos⁻¹ and tan⁻¹.
3. Press Enter or = to get the answer. Press the Up arrow to bring back your last calculation, or Esc to clear the box.
4. Use Ans to carry the last answer into a new calculation, and the ×10ˣ key for scientific notation: 3E8 means 3 × 10⁸.
5. Click any line in the history to reuse it. Clear history removes the whole list.

• Check the Degrees/Radians switch first. sin(30) is 0.5 in degrees but about -0.988 in radians, the most common reason for a wrong trig answer.
• You can skip the × sign: 2pi, 3(4+1) and 5sqrt(2) are all read as multiplications. A comma works as a decimal point too, so 2,5 is the same as 2.5.
• log is base 10 and ln is base e. log(1000) = 3 and ln(e) = 1. Mixing them up changes every answer in a logarithm question.
• Use brackets to make the order clear: 1/(2×3) is not the same as 1/2×3.

What happens when I get an error?

The calculator explains the problem under the input instead of just showing Error. For example, tan 90° is undefined in degrees, and the square root of a negative number has no real answer.

Does it work on a phone?

Yes. On phones the calculator's keypad replaces the phone keyboard, so the maths keys are there from the start.

Is my history saved?

Your last 30 calculations are kept in this browser's local storage on this device. Nothing is uploaded. Clear history removes them, and so does clearing your browser data.