仕組みと動作原理
DAY関数はExcel業務を効率化する代表的な関数です。Extracts the day of the month (1 to 31) from a date value. 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。
構文.
標準Excel表記法=DAY(serial_number)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 date value to extract the day from.
指定例:A2具体的な計算例
ステップ別の実務シナリオExtract Day of Month
Extract calendar day number from timestamp.
| Date | Day of Month |
|---|---|
| 2025-05-20 | — |
| 2025-08-31 | — |
=DAY(A2)Evaluates DAY over the sample table cells, placing the verified output in cell B2.
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。
=DAY()出力される値の特性
Returns number 20 based on sample evaluation criteria and active cell references.
実務上のベストプラクティス
- Use DAY to check if an invoice date matches a specific cutoff day of the month.
よくあるミスと注意点
- Supplying text strings that Excel does not recognize as dates returns #VALUE!.
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 DAY 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: =DAY(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 DAY?↓
Supplying text strings that Excel does not recognize as dates returns #VALUE!.
Does DAY work identically in Google Sheets?↓
Yes, DAY is supported in both Microsoft Excel and Google Sheets with standard evaluation behavior.