CSV Column Type Detector
Detect likely text, number, date, boolean, and empty column types
CSV Column Type Detector — what it does
Scan every column and get a verdict on what kind of data it holds: text, number, date, boolean or empty. It profiles a file you did not create, before you write a formula, design a database table or trust a column to behave like the numbers it appears to contain.
When this tool helps
- Designing table columns or an import mapping for a dataset you have just received.
- Confirming that an amount column is genuinely numeric and not text with stray currency symbols.
- Finding columns that are entirely empty and can be dropped before analysis.
How to use it
- Choose the CSV file.
- Process the detection.
- Review the type assigned to each column.
- Download the report for your documentation.
Accuracy, limits, and good practice
- A column of postcodes or product codes made only of digits will read as numeric, which is exactly how leading zeros get lost on import.
- Detection is based on the values present, so a mostly numeric column containing one text entry may still be classified as text.
- Boolean detection recognises common true and false spellings; localised or numeric flags such as 1 and 0 read as numbers instead.
Frequently asked questions
Does it change my file?
No. This tool only reports; the CSV is left exactly as it was and no output data file is written.
How do I keep leading zeros?
Import the column as text in your destination system, or prefix values so they cannot be read as numbers.
Why is a date column reported as text?
Because the format is not parseable as written. Run the date normaliser to standardise it, then detect again.
Related tools on this site
- Excel Worksheet Comparison — Compare two worksheets cell by cell and export a difference report
- CSV Column Extractor — Keep only selected columns and download a new CSV
- CSV Outlier Detector — Find numeric outliers with the interquartile-range method
Everything above runs inside this page. CSV Column Type Detector needs no account, no upload, and no server round trip — close the tab and nothing is left behind.
CSV 欄位類型偵測能做什麼
掃描每一個欄位，判定它裝的是哪一類資料：文字、數字、日期、布林或空白。在你為別人給的檔案寫公式、設計資料表，或直接假設某欄真的是數字之前，先做一次剖析。
什麼時候用得上
- 為剛收到的資料集設計資料表欄位或匯入對應。
- 確認金額欄真的是數值，而不是夾雜貨幣符號的文字。
- 找出完全空白、可在分析前直接移除的欄位。
使用步驟
- 選擇 CSV 檔案。
- 執行偵測。
- 檢視每個欄位被判定的型別。
- 下載報告存入文件。
精確度、限制與實務建議
- 全由數字組成的郵遞區號或商品代碼會被判為數值，這正是匯入時前置零消失的原因。
- 偵測依實際值判斷，因此以數字為主但夾雜一筆文字的欄位仍可能被判為文字。
- 布林偵測認得常見的 true/false 寫法；本地化字詞或 1 與 0 這類旗標會被判為數字。
常見問題
會改到我的檔案嗎？
不會。本工具只做報告，CSV 維持原樣，也不會輸出資料檔。
怎麼保住前置零？
在目標系統中以文字方式匯入該欄，或替值加上前綴，讓它不會被判讀成數字。
日期欄為什麼被判成文字？
因為現有寫法無法解析為日期。請先用日期格式統一工具標準化，再重新偵測。
本站相關工具
- Excel 工作表比較 — 逐一比較兩個工作表的儲存格並匯出差異報告
- CSV 欄位提取 — 保留選取欄位並下載新的 CSV
- CSV 離群值偵測 — 使用四分位距方法找出數值欄位中的離群值
以上步驟全部在這個頁面內完成，CSV 欄位類型偵測 不需要註冊、不上傳檔案、也不經過伺服器，關閉分頁後不會留下任何資料。