CALCULATE WITH CONFIDENCE

Number Fundamentals & Precision

Significant Figures Counter

Count significant digits without guessing ambiguous trailing whole-number zeros.

Exact arithmetic

Inspect written significant digits

Ambiguity is reported
  1. 1EnterProvide the known values
  2. 2CalculateResults update automatically
  3. 3VerifyReview the details and units
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Significant figures

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Understand the subject

How are significant figures counted?

The notation matters: leading zeros are placeholders, while written decimal trailing zeros can express intended precision.

Use it to inspect a written value before applying a measurement or reporting convention.

The key rule

What stays true

See the idea

Visual explanation

Example

Apply it

Scientific notation can state intent clearly: 1.20e3 has three significant figures.

Do not infer hidden precision from a plain trailing whole-number zero.

Quick guide

How to use this calculator

  1. Enter the value exactly as written, optionally in scientific notation.
  2. Read one count or an ambiguity range.
  3. Add a decimal marker or use scientific notation to express trailing-zero intent.

Calculation method

Notation carries precision information

Leading zeros are place holders. Embedded zeros and written decimal trailing zeros are significant. In a whole number such as 1200, the trailing zeros may or may not be significant, so a range is the truthful answer.

Worked example

Clarifying 1200

Plain 1200 may carry two to four significant figures, while 1200. explicitly carries four.

sig(1200) = 2–4; sig(1200.) = 4

Supported inputs

Precision and limits

Scientific notation

Use forms such as 1.20e3 to make three significant figures explicit.

Exponent

Use an exponent from −100 to 100.