仕組みと動作原理
MONTH関数はExcel業務を効率化する代表的な関数です。Extracts the month (1 to 12) 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=MONTH(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 from which to extract the month.
指定例:A2具体的な計算例
ステップ別の実務シナリオExtract Month from Date
Retrieve month integer (1-12) from invoice date.
| Invoice Date | Month Number |
|---|---|
| 2025-05-20 | — |
| 2025-10-04 | — |
=MONTH(A2)Evaluates MONTH 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。
=MONTH()出力される値の特性
Returns number 5 based on sample evaluation criteria and active cell references.
実務上のベストプラクティス
- Pair with CHOOSE to convert month numbers to three-letter abbreviations: =CHOOSE(MONTH(A2), "Jan", "Feb", ...).
よくあるミスと注意点
- If the cell contains a plain number like 5 instead of a real date, MONTH treats it as day 5 of year 1900.
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 MONTH 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: =MONTH(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 MONTH?↓
If the cell contains a plain number like 5 instead of a real date, MONTH treats it as day 5 of year 1900.
Does MONTH work identically in Google Sheets?↓
Yes, MONTH is supported in both Microsoft Excel and Google Sheets with standard evaluation behavior.