What are significant figures?

Significant figures (or significant digits) are the meaningful digits in a number that contribute to its precision. For example, 0.00430 has 3 significant figures: 4, 3, and the trailing zero after the decimal.

How does rounding to sig figs differ from rounding to decimal places?

Rounding to decimal places fixes the number of digits after the decimal point. Rounding to significant figures fixes the total number of meaningful digits regardless of where the decimal point falls. For example, 12345 rounded to 3 sig figs is 12300, not 12345.000.

What is scientific notation?

Scientific notation expresses a number as a value between 1 and 10 multiplied by a power of 10. For example, 0.00430 in scientific notation is 4.30 × 10⁻³. It makes very large and very small numbers easier to read and compare.

Are trailing zeros significant?

Trailing zeros after a decimal point are significant (e.g., 4.50 has 3 sig figs). Trailing zeros in a whole number without a decimal point are ambiguous — scientific notation removes this ambiguity.

Can I enter numbers in scientific notation?

Yes. You can type numbers like 1.23e-4 or 6.022e23 and the calculator will parse them correctly.

Significant Figures Calculator

Enter any number and choose how many significant figures to keep — get the rounded result plus its scientific notation instantly.

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Significant Figures: 3

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Summary

This calculator rounds any number to a chosen number of significant figures and displays the result in both standard decimal notation and scientific notation. It correctly handles integers, decimals, very large numbers, and very small numbers including those in scientific notation input format. Understanding significant figures is essential in science, engineering, and any field where measurement precision matters.

How it works

Enter the number you want to round in the input field.
Choose the number of significant figures using the slider or type a value.
The calculator rounds your number to the specified sig figs.
Results are shown in standard notation and scientific notation.

Use cases

Round measured values in physics or chemistry lab reports.
Express engineering calculations to the correct precision.
Convert large or small numbers to scientific notation.
Check your manual sig fig rounding for homework or exams.
Understand which digits in a measurement are significant.
Quickly format numbers for scientific publications.

Frequently Asked Questions

Last updated: 2026-06-04 · Reviewed by Nham Vu