At the heart of Renamio is its rule system. Each rule represents a single filename transformation, and you can stack multiple rules together to run them in sequence — like a pipeline.

This guide walks you through all 16 rules, with real-world examples for each one.

Basic Rules

1. Insert Text

Add content at a specific position in the filename.

5 insertion positions supported:

Prefix: Add to the beginning. IMG_001.jpg → Vacation_IMG_001.jpg
Suffix: Add to the end. IMG_001.jpg → IMG_001_backup.jpg
At position: Insert at the Nth character. abcdef → abc123def
Before text: Insert before a specific word. photo_001.jpg → Vacation_photo_001.jpg
After text: Insert after a specific word. photo_001.jpg → photo_Vacation_001.jpg

Common uses: Add a project name as a prefix, append a date as a suffix, insert separators at specific positions.

2. Find and Replace

Replace specific text in the filename with something else.

Three replacement scopes:

Replace all: Replace every match
Replace first: Only replace the first occurrence
Replace last: Only replace the last occurrence

Common uses: Change IMG_ to Photo_, remove the word Copy from filenames, fix typos.

3. Remove Content

Delete specific content from the filename.

Three removal modes:

By text: Delete a specific string
By position: Delete M characters starting from position N
Clear filename: Remove the entire filename (keeping the file extension)

Common uses: Strip ad text from filenames, remove unnecessary prefixes or suffixes.

4. Case Conversion

Standardize the letter casing in filenames.

6 conversion options:

All uppercase: readme.md → README.md
All lowercase: README.md → readme.md
Capitalize each word: hello world.txt → Hello World.txt
Capitalize first letter only: hello world.txt → Hello world.txt
Invert case: Hello.txt → hELLO.txt

Common uses: Enforce consistent naming conventions for code files, clean up mixed-case filenames.

Sequence and Numbering

5. Sequence Formatting

Add sequentially numbered prefixes or suffixes to files.

6 sequence types:

Numbers: 001, 002, 003 (with optional zero padding)
Lowercase letters: a, b, c
Uppercase letters: A, B, C
Chinese numerals (lowercase): 一, 二, 三
Chinese numerals (uppercase/formal): 壹, 贰, 叁
Roman numerals: I, II, III
Custom character set: Define your own repeating characters

Configurable parameters: Starting number, step, repeat count, fixed digit length.

Common uses: Number photos sequentially, add chapter numbers to documents, add track numbers to music files.

6. Zero Padding

Standardize the number of digits in numeric parts of filenames.

Add zero padding: 3 → 003, 12 → 012
Remove zero padding: 003 → 3, 012 → 12

Common uses: Make numbered files sort correctly in file explorers.

7. Random Padding

Insert random strings into filenames.

Supports pools of digits, lowercase letters, uppercase letters, and Chinese numerals, with customizable length and insertion position.

Common uses: Add random identifiers to files, generate unique filenames.

Date and Time

8. Date Rule

Use date information in filenames.

Two modes:

Add date: Insert the current date or a specific date into the filename. report.docx → 2026-05-01_report.docx
Reformat existing date: Convert a date already in the filename from one format to another. 20260501_report.docx → 2026-05-01_report.docx

Supports all common date formats: YYYY-MM-DD, YYYYMMDD, YYYY/MM/DD, and more.

Common uses: Prepend a date to filenames, unify date formats across files.

Text Processing

9. Conditional Replace

Replace content based on its position relative to a target string.

Four positioning modes:

N characters before the target string
N characters after the target string
All characters before the target string
All characters after the target string

Example: Filename Report_2026_Final.docx, target string is _2026_, choose "all characters before target" and replace with nothing → Final.docx

Common uses: Delete everything before or after a marker, extract a specific portion of a filename.

10. Regular Expression

Use Regular Expressions for advanced find-and-replace operations.

Supports full regex syntax, capture group references ($1, $2), and flags (g, i, m).

Example: Use (\d{4})(\d{2})(\d{2}) to match a date, replace with $1-$2-$3, and 20260501 becomes 2026-05-01.

Common uses: Complex pattern matching, batch-extract specific information from filenames, format conversion.

11. Clean Characters

Remove noisy or unwanted characters from filenames.

What it cleans:

Brackets and their contents: Supports (), [], {} (auto-handles both Chinese and English brackets)
Consecutive extra spaces
Consecutive extra underscores and hyphens

Example: FileName (Copy) (1).docx → FileName.docx

Common uses: Remove ad markers from downloaded files, strip system-generated copy labels.

12. Swap Parts

Split the filename by a separator, then swap the two parts.

Example: Jay Chou - Sunny Day.mp3 split by - → Sunny Day - Jay Chou.mp3

Common uses: Reorder "Artist - Title" to "Title - Artist", swap two segments of a filename.

13. Transform Rule

Apply various format transformations to filenames.

English transformations: Various case conversion combinations

Chinese transformations:

Chinese to Pinyin: 你好世界 → ni_hao_shi_jie
Traditional to Simplified Chinese: 計算機 → 计算机

Number transformations:

Number to formal Chinese numerals: 123 → 壹佰贰拾叁
Number to standard Chinese numerals: 123 → 一百二十三
Chinese numerals to number: 一百二十三 → 123

Common uses: Romanize Chinese filenames for cross-platform compatibility, standardize number formats, convert between Traditional and Simplified Chinese.

Advanced Rules

14. Metadata Rule

Name files using their actual file information.

Supported metadata includes:

File info: Filename, file extension, size, creation time, modification time

File hash: MD5, SHA1, SHA256

Image info: Width, height

Photo EXIF: Capture time, camera manufacturer, camera model, aperture, shutter speed, ISO, focal length, lens model

Template syntax: ${photo.dateTime}_${index} names each photo using its capture date plus a sequence number.

Common uses: Name photos by capture date, include file size in filenames, organize photos by camera info.

15. Fix Extension

Detect a file's actual type by reading its content, then automatically correct a wrong file extension.

Example: file.zip111 → file.zip, document.pdf that's actually a Word file → document.docx

Common uses: Fix incorrectly changed extensions, repair extensions lost or corrupted during download.

16. JS Script

Write custom renaming logic in JavaScript.

When the built-in rules aren't enough, you can code any renaming logic you need. AI-assisted code generation is also supported.

Common uses: Read file content to determine the new filename, implement complex conditional logic, call external APIs.

Rule Combinations: The Real Power

A single rule is already useful, but the real power of Renamio comes from combining rules.

Say you want to organize camera photos into this format: 2026-Paris-001.jpg

You can chain three rules together:

Metadata Rule: Replace the filename with the capture date
Insert Text: Add the location as a prefix Paris-
Sequence Formatting: Add a three-digit number at the very beginning

Three rules run in order, done in one go.

A more complex example:

Clean Characters: Remove bracketed content from filenames
Find and Replace: Change _ to -
Case Conversion: Convert everything to lowercase
Date Rule: Add a date prefix
Sequence Formatting: Add a numbered suffix

AI Assistance: Just Describe What You Want

If you don't want to pick rules one by one, try the AI feature. Just describe what you need in plain language:

"Name all photos by capture date, add a sequence number, format: 2026-05-01_001"

AI will analyze your request, assemble the right combination of rules, and show you a preview. Not happy with the result? Keep the conversation going and refine it.

Wrapping Up

These 16 rules cover everything from simple to complex renaming scenarios. You don't need to memorize them all — just know they exist, and you'll find the right one when you need it.

Want detailed usage for each rule? Check out the Renamio documentation.

All 16 Renaming Rules in Renamio, Explained