Encoding Mark · Free Local Tool

File BOM Detector

Checks if the beginning of the file contains a UTF-8, UTF-16, or UTF-32 BOM and displays the preceding bytes.

No uploadsMobile-friendlyTheme support

What is the Archive BOM and Coding Markup Checker?

Checks if the beginning of the file contains a UTF-8, UTF-16, or UTF-32 BOM and displays the preceding bytes. ToolHub places the core computing entirely within the browser, allowing immediate use on both desktop and mobile devices, without the need to register an account or send content to the backend.

How to use this tool?

  1. Enter the data according to the field prompts and select the required processing method.
  2. Click "Process Now" to view the results, indicator summary and necessary error messages.
  3. After confirming that the content meets actual needs, you can copy the results or download them into files for further use.

Suitable use cases

Troubleshoot text import failures, garbled characters, CSV and code encoding issues. All processing is completed in the current page, which is especially suitable for workflows that do not want to post internal data to remote services.

Interpretation of results and precautions

The absence of BOM does not mean that the encoding cannot be determined. Many UTF-8 files do not originally contain BOM. Tools will validate basic input formats and provide readable error messages, but production environments should still be reconfirmed against source specifications, business rules, or professional requirements.

Browser and device support

File BOM Detector supports current Chrome, Edge, Firefox, and Safari releases. Mobile and desktop layouts use the same validation rules documented on this page.

Frequently Asked Questions

Will the File BOM and Encoding Markup Checker upload data to the server?
No. Tool functions are executed directly within the current browser tab, and input and generated results will not be uploaded or saved by ToolHub.
What use cases are the Archive BOM and Encoding Markup Checkers suitable for?
Troubleshooting text import failures, garbled characters, CSV and code encoding issues
Do I need to install software before using the File BOM and Coding Markup Checker?
No need. Use a desktop or mobile browser that supports modern JavaScript, and no account is required.
What are the limitations of this tool?
The absence of BOM does not mean that the encoding cannot be determined. Many UTF-8 files do not originally contain BOM.
Is manual inspection required after the results are generated?
Needed. Tools can assist with calculations, conversions, or formatting, but before going online, importing data, or making business decisions, the results should still be reviewed according to actual specifications.

File BOM Detector: inputs, output, and reproducible example

Use the free File BOM Detector online. Fast, private, mobile-friendly, and processed directly in your browser.

What this page actually processes

FieldControlDefault exampleValidation role
Select Text or Binary FilesLocal fileChoose a local fileSelect Text or Binary Files is read by the browser as a local file value before the tool runs.

Reproduce the built-in example

Start with Select Text or Binary Files = Choose a local file, then run File BOM Detector. Change one input at a time so the effect on the result remains traceable.

After validating select text or binary files, the page displays its result in the output workspace and enables the relevant copy or download action.

When to use it and how to interpret the result

Troubleshoot text import failures, garbled characters, CSV and code encoding issues. All processing is completed in the current page, which is especially suitable for workflows that do not want to post internal data to remote services.

Limits and checks before use

The absence of BOM does not mean that the encoding cannot be determined. Many UTF-8 files do not originally contain BOM. Tools will validate basic input formats and provide readable error messages, but production environments should still be reconfirmed against source specifications, business rules, or professional requirements.

Page verification record

Controls inspected1 documented inputsResult pathValidate → process → review → copy/downloadLast content review2026-09-02