Percent Error and Significant Figures in Converted Values ガイド

このガイドは説明します: How rounding, measured precision, and percent error affect values moved between calculators and reports.

ガイド 更新 2026-05-11

手順

Use this guide when a converted number affects lab notes, schoolwork, specifications, spreadsheet checks, and quality reports. A reliable result keeps the original value, source unit, target unit, conversion factor, and rounding choice visible.

The goal is not to memorize every factor. The goal is to make the calculation traceable enough that someone else can review it later.

チェックリスト

  • Keep the original measured precision visible.
  • Round converted values only after the final calculation.
  • Use percent error when comparing a measured value with an accepted value.

役立つ事実

Exact conversion factors do not add measurement precision to the original value.

実用例

Percent error = absolute error / accepted value x 100.

2.54 cm per inch is exact, but a ruler reading may not be exact.

A value measured to 0.1 should not be reported with unnecessary decimal places.

よくある質問

What should I check first?

Confirm the source unit and target unit before changing the number.

When should I round?

Round at the end, after formulas and related conversions are complete.

Which calculator should I use next?

Use the related calculators below to check the main values from this guide.

関連計算機

Percentage Calculator Average Calculator 計算機 Scientific Calculator

要点

A useful conversion is traceable: it shows the original unit, the target unit, the factor used, and the rounding decision.