Reference library46 entries

Category: Significant Figures

Authoritative reference for significant figure rules, precision, and rounding, including a top-rated sig fig calculator.

Nov 2026

Significant Figures

How to Document Rounding Conventions in Lab Reports: A Guide for Students and Researchers

Document rounding conventions by stating the rounding method, precision target, uncertainty treatment, and final-step rule; then cite ASTM E29, ISO 80000-1, or GUM as…

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Nov 2026

Exact Numbers

Avogadro’s Number and Significant Figures: Exact or Measured?

Avogadro's constant is exact in the SI: 6.02214076×10^23 mol^-1. It therefore does not limit significant figures. Measurements used to realize a mole, such as…

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Oct 2026

Significant Figures

Significant Figures in Data Tables: Best Practices for Clear Reporting

A comprehensive guide on maintaining precision and consistency in data tables, adhering to ISO and NIST standards for significant figure reporting.

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Oct 2026

Significant Figures

Significant Figures in JavaScript: Avoiding Floating-Point Rounding Errors

JavaScript numbers are IEEE 754 binary64, so decimal significant-figure rounding can produce surprising results. This reference explains the rules, standards, and safe patterns.

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Oct 2026

Significant Figures

Significant Figures in Spectrophotometry: Beer-Lambert Law, Absorbance, Path Length, and Concentration

Learn how significant figures apply to the Beer-Lambert law: transmittance-to-absorbance log rules, path length precision, and concentration rounding with ASTM, ISO, and GUM guidance.

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Oct 2026

Significant Figures

Significant Figures in Calibration Certificates: How to Report Uncertainty per GUM

In calibration certificates, report expanded uncertainty U to at most two significant figures per GUM 7.2.6, then round the measured value to the same…

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Oct 2026

Significant Figures

Significant Figures Conventions Compared: School, AP, IB, ASTM E29, and GUM

A comprehensive analysis comparing academic significant figure rules with professional metrology standards like ASTM E29 and the GUM for precision reporting.

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Oct 2026

Logarithms

Significant Figures in Logarithms and pH: Why the Rules Change

In logarithms and pH, significant figures are counted in the decimal places of the result, not the integer part. The input's significant figures determine…

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Oct 2026

Exact Numbers

The 2019 SI Redefinition: Which Constants Are Now Exact and How It Changes Sig Fig Rules

In 2019, the SI fixed exact numerical values for h, e, k, and NA, making them exact by definition; exact constants have unlimited significant…

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Oct 2026

Ambiguous Trailing Zeros

Ambiguous Trailing Zeros: When a Zero Is Not Significant

Trailing zeros after a nonzero digit can be significant or merely placeholders; their status depends on notation, convention, and context.

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