# Count Significant Digits in a Written Number

> Count meaningful digits while preserving the written zeros and decimal notation.

Page: https://askcalculators.com/math/significant-figures-counter/
Definition: https://askcalculators.com/math/significant-figures-counter/definition.json
JSON Schema: https://askcalculators.com/math/significant-figures-counter/schema.json
Version: 1.0.0
Maintained by: AskCalculators (software project; not a credentialed reviewer)
Qualified review: pending. Automated checks do not establish professional approval.
Page status: Live
Review status: Pending

## Use
Open the calculator page and enter values. Query-string parameters can restore and bookmark a calculation.
Example: https://askcalculators.com/math/significant-figures-counter/?value=0.004500

## Inputs
- value: Written number; type=text; required; default=0.004500

## Outputs
- significantFigures: Significant figures; format=integer; primary
- decimalPlaces: Decimal places; format=integer
- normalized: Normalized numeric value; format=text
- scientificNotation: Scientific notation; format=text

## Formula
leading zeros are not significant; zeros between nonzero digits are significant; trailing decimal zeros are significant

## Rules
- Empty optional inputs are undefined, not zero.
- Hidden conditional inputs are ignored.
- Do not invent missing required inputs.