Best Free Online Developer Tools to Use in 2026
A practical, opinionated list of the best free online developer tools worth using in 2026, organized by category so you can find what you need fast.
Aug 08, 2026
Significant Figures Calculator
Count significant figures and round numbers to a specified number of sig figs.
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Sig Fig Counter & Rounder
Number
0.004500
Significant Figures
4
Rounded Value
0.00450
Scientific Notation
4.50 × 10⁻³
Sig Fig Rules Applied
--
How to Use
- Enter a number — Type any number with or without decimal point.
- Set sig figs — Optionally specify how many significant figures to round to.
- Calculate — View the count, rounded value, and scientific notation with detailed rule explanations.
What are Significant Figures?
Significant figures (sig figs) are the digits in a number that carry meaning contributing to its measurement precision. The rules for counting sig figs are:
- All non-zero digits are always significant.
- Zeros between non-zero digits are always significant.
- Leading zeros (before non-zero digits) are never significant.
- Trailing zeros after a decimal point are significant.
- Trailing zeros in a whole number without a decimal are not significant.
Frequently Asked Questions
How many sig figs does 100 have?
Without a decimal point, 100 has 1 significant figure. The trailing zeros are not significant. If written as 100. or 100.0, it would have 3 or 4 sig figs respectively.
Why are leading zeros not significant?
Leading zeros only serve to place the decimal point. For example, 0.0045 has 2 sig figs (the zeros are just placeholders). This avoids ambiguity in representing small numbers.
What is the difference between significant figures and decimal places?
Decimal places count digits after the decimal point regardless of significance. Significant figures count all meaningful digits from the first non-zero digit, providing a measure of overall precision.
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