仕組みと動作原理
ROUND関数はExcel業務を効率化する代表的な関数です。数値を指定した桁数（小数点以下または整数部）に四捨五入します。 複雑な集計や参照処理を簡素化し、データ分析の精度と生産性を飛躍的に高めます。
💡 わかりやすい要約
Rounds a decimal number to a specific number of decimal places (like rounding 19.9567 to 19.96).
"Think of this like checking your height. If you are 138.6 cm, you might round it to the nearest whole number, which is 139 cm."
構文.
標準Excel表記法=ROUND(数値, 桁数)引数一覧.
この関数で指定できるすべての引数について詳しく解説します。
The number you want to round.
指定例:A2The number of digits to which you want to round the number.
指定例:2具体的な計算例
ステップ別の実務シナリオRound Financial Rates
Round the decimal values in column A to exactly 2 decimal places.
| Exact Price | Qty | Rounded Price | ||
|---|---|---|---|---|
| 19.9567 | 5 | — | — | — |
| 4.5212 | 12 | — | — | — |
| 8.0099 | 2 | — | — | — |
=ROUND(A2, 2)Evaluates ROUND over the sample table cells, placing the verified output in cell C2:C6.
数式ジェネレーター
ウィザードを開く引数を入力するだけで、シートにそのまま貼り付けて使える数式を作成できます。
=ROUND()出力される値の特性
Returns "Calculated output" based on sample evaluation criteria and active cell references.
実務上のベストプラクティス
- To always round up (away from zero), use ROUNDUP. To always round down (toward zero), use ROUNDDOWN.
- To round to a multiple of a specific number (like rounding to the nearest 0.05), use MROUND.
よくあるミスと注意点
- Rounding values can introduce small math differences when summing rounded numbers vs summing exact values.
各プラットフォーム対応表
実際のExcelおよびGoogleスプレッドシートの計算エンジン仕様に基づいた検証結果です。
Core standard function supported across all modern and legacy Microsoft Excel versions (365, 2021, 2019, 2016, 2013, 2010), as well as Excel for the Web and Mac.
100% compatible with Google Sheets. Uses identical argument order, data types, and standard calculation logic.
よくある質問と回答
技術解説Can I use ROUND across different worksheets in Excel?↓
Yes. You can reference cells located on other sheets by including the sheet name followed by an exclamation mark, for example: =ROUND(Sheet2!A2:A10). If the sheet name contains spaces, enclose it in single quotes: ='Q1 Report'!A2:A10.
What is the most common reason for errors in ROUND?↓
Rounding values can introduce small math differences when summing rounded numbers vs summing exact values.
Does ROUND work identically in Google Sheets?↓
Yes, ROUND is supported in both Microsoft Excel and Google Sheets with standard evaluation behavior.