Significant Figures
Count, identify, and round to significant figures with digit-by-digit highlighting
About this calculator
The Significant Figures Calculator counts the sig figs in any number and rounds it to your chosen precision, showing which digits are significant and which rules apply. Enter a measurement or calculation result to identify leading zeros, captive zeros, and trailing decimals correctly. Essential for chemistry, physics, and engineering lab work.
How to use the Significant Figures calculator
- Enter the values for your problem into the input fields.
- Read the result — it updates instantly as you type.
- Check the formula and the visual explanation to follow how the answer was found.
- Copy the page URL to share the exact calculation.
Common examples
- 1234 rounded to 2 sig figs → 1200 (sig figs: 1, 2)
- 0.00456 has 3 sig figs (4, 5, 6) — leading zeros are not significant
- 98765 rounded to 3 sig figs → 98800
- 0.02030 has 4 sig figs (2, 0, 3, 0) — trailing zero after decimal is significant
- 500.0 has 4 sig figs — decimal point makes all trailing zeros significant
Frequently asked questions
How does the Significant Figures calculator work?
Enter your values and the calculator applies the exact mathematical method for this problem, showing the result together with the formula it used. Everything is computed with high-precision arithmetic, so the answer you see is not limited by ordinary floating-point rounding.
When would I use the Significant Figures calculator?
It is useful for homework and exam preparation, for checking work done by hand, and whenever a step in a larger problem needs this calculation done quickly and reliably.
How accurate are the results?
Calculations run at 30 significant digits of precision internally. Displayed values are rounded for readability, but the underlying result is far more precise than a typical hand or pocket-calculator computation.
Can I share a specific calculation with someone else?
Yes. Every value you enter updates the URL, so copying the address bar and sharing the link reopens the exact same calculation for whoever clicks it.