Significant Figures Calculator

How to count significant figures

1. Type a number, such as 0.004560 or 1.20e5.
2. The count of significant figures appears.
3. Choose how many to round to.

Frequently asked questions

Which zeros count?

Zeros between digits always count, leading zeros never do, and trailing zeros count only when there is a decimal point. In 1200 they are ambiguous; write 1.200e3 to show four.

How many significant figures should a result have?

For multiplying and dividing, as many as the least precise value. For adding and subtracting, round to the least precise decimal place.

How do I round to significant figures?

Keep that many digits starting from the first non-zero one and round the last. 0.004567 to two significant figures is 0.0046.