Free Online Converter Tools
Use free converter tools for JSON formatting, Base64 encoding, URL encoding, CSV to JSON, YAML to JSON, XML to JSON, Markdown to HTML, HTML to Markdown, timestamps, and number bases.
Best Converter Tools to Start With
Curated entry points for the strongest converter workflows.
JSON Formatter
Format, validate, and beautify JSON instantly — with clear error messages, Tree View, Diff mode, and Schema validation.
Base64 Encoder/Decoder
Encode text to Base64 or decode Base64 to plain text — with URL-safe mode, auto-detect, and size stats.
URL Encoder/Decoder
Encode and decode URL strings with special characters.
CSV to JSON Converter
Convert CSV files to JSON arrays instantly — with header mapping, delimiter options, and type inference.
YAML to JSON Converter
Convert YAML to JSON and JSON to YAML — for config files, CI pipelines, and Kubernetes manifests.
Markdown to HTML Converter
Convert Markdown to clean, semantic HTML with live preview — supports GFM tables, task lists, syntax highlighting, and custom sanitization.
CSS to LESS Converter
Convert plain CSS into cleaner LESS with optional selector nesting, LESS variables, formatting, copy, and download output.
CSS to SCSS Converter
Convert plain CSS into cleaner SCSS with optional selector nesting, Sass variables, formatting, copy, and download output.
Converter Tools by Use Case
Browse tools grouped by what you need to get done.
JSON and Data Converters
Clean messy JSON, convert tabular data into objects, or move between common data formats used by developers, APIs, and content systems.
JSON Formatter
Format, validate, and beautify JSON instantly — with clear error messages, Tree View, Diff mode, and Schema validation.
CSV to JSON Converter
Convert CSV files to JSON arrays instantly — with header mapping, delimiter options, and type inference.
YAML to JSON Converter
Convert YAML to JSON and JSON to YAML — for config files, CI pipelines, and Kubernetes manifests.
XML to JSON Converter
Parse and convert XML to clean JSON instantly — attributes, namespaces, and nested elements handled.
Encoding and Decoding
Encode and decode values for URLs, tokens, payloads, and data strings that need to be safely transported or inspected.
Markdown and HTML
Convert between Markdown and HTML for blog publishing, documentation, and CMS workflows. Preview Markdown live and generate clean, publish-ready HTML.
Markdown to HTML Converter
Convert Markdown to clean, semantic HTML with live preview — supports GFM tables, task lists, syntax highlighting, and custom sanitization.
HTML to Markdown Converter
Convert HTML into clean, readable Markdown — preserving headings, links, images, lists, and tables.
Markdown Table Generator
Create GFM Markdown tables visually — add rows/columns, align cells, import from CSV/spreadsheet paste, and copy the formatted table code.
Code and Stylesheet Converters
Move code between adjacent formats during frontend migrations and cleanup work. Convert CSS into LESS or SCSS source, then pair it with CSS cleanup tools when needed.
CSS to LESS Converter
Convert plain CSS into cleaner LESS with optional selector nesting, LESS variables, formatting, copy, and download output.
CSS to SCSS Converter
Convert plain CSS into cleaner SCSS with optional selector nesting, Sass variables, formatting, copy, and download output.
CSS to Tailwind Converter
Convert CSS declarations to Tailwind CSS utility classes — supports margin, padding, flex, grid, typography, colors, and arbitrary value fallbacks.
CSS Beautifier / Formatter
Format, indent, and beautify minified or messy CSS code — with configurable indentation and sorting options.
Time and Number Converters
Convert Unix timestamps, binary, decimal, and hexadecimal values. Useful when debugging logs, APIs, analytics events, and low-level data formats.
Unix Timestamp Converter
Convert between Unix timestamps and human-readable dates across any timezone — with millisecond precision and real-time epoch display.
Number Base Converter
Convert numbers between binary, decimal, hexadecimal, octal, and any custom base — with bit grouping, signed integers, and step-by-step explanation.
All Converter Tools
57 free tools — no sign-up required.
Base64 Encoder/Decoder
Encode text to Base64 or decode Base64 to plain text — with URL-safe mode, auto-detect, and size stats.
CSV to HTML Table Converter
Convert CSV or TSV data into a clean HTML table with border, striped rows, and responsive wrapper options.
CSV to JSON Converter
Convert CSV files to JSON arrays instantly — with header mapping, delimiter options, and type inference.
CSV to Multiline Converter
Extract a column from CSV data as a flat line-by-line list. Choose any column, skip the header, and download or copy the result.
CSV to SQL Converter
Convert CSV data into SQL INSERT statements for MySQL, PostgreSQL, SQLite, or SQL Server with optional CREATE TABLE output.
CSV to TSV Converter
Convert CSV (comma-separated values) to TSV (tab-separated values) online. Supports custom delimiters, quoted fields, and auto-detection.
CSV to XML Converter
Convert CSV or TSV data into well-formed XML with configurable root and row element names, attribute or element mode, and optional XML declaration.
CSV Viewer
View, search, and sort CSV data as an interactive table. Supports comma, semicolon, tab, and pipe delimiters.
EM to Percent Converter
Convert CSS EM values to percentage. For font-size, 1em = 100% — a direct 1:1 relationship. Supports bulk input and includes a reference table.
EM to Point Converter
Convert CSS EM values to typographic point (pt) units. Set the parent font size, enter EM values, and get the point equivalent. Useful for @media print stylesheets.
EM to PX Converter
Convert EM values to pixels instantly. Set the parent element font size, enter one or multiple EM values, and get the pixel equivalent with a full reference table.
HTML to CSV Converter
Extract table data from HTML and convert it to CSV. Supports multiple tables, minimal or always-quote modes, and download as .csv.
HTML to JSON Converter
Convert HTML tables, lists, or DOM trees to JSON. Extracts structured data from HTML without writing a parser.
HTML to JSX Converter
Convert HTML to JSX for React — converts class to className, for to htmlFor, self-closes void elements, and converts inline styles to JSX objects.
HTML to Markdown Converter
Convert HTML into clean, readable Markdown — preserving headings, links, images, lists, and tables.
HTML to XML Converter
Convert HTML to well-formed XML. Closes void elements, lowercases tags, escapes attributes, and adds an optional XML declaration.
Inches to Pixels Converter
Convert inches to CSS pixels using the standard 96dpi formula (1in = 96px). Supports bulk input and includes a reference table from 1/16 inch to 10 inches.
JSON Formatter
Format, validate, and beautify JSON instantly — with clear error messages, Tree View, Diff mode, and Schema validation.
JSON to CSV Converter
Convert a JSON array of objects to CSV. Flattens nested objects with dot-notation columns and handles arrays within values.
JSON to XML Converter
Convert JSON to XML online. Nested objects and arrays are mapped to XML elements with configurable root element name and optional XML declaration.
LESS to Stylus Converter
Convert LESS code to Stylus indented syntax. Removes braces and semicolons, converts @variable to bare variable assignments.
Markdown Table Generator
Create GFM Markdown tables visually — add rows/columns, align cells, import from CSV/spreadsheet paste, and copy the formatted table code.
Markdown to HTML Converter
Convert Markdown to clean, semantic HTML with live preview — supports GFM tables, task lists, syntax highlighting, and custom sanitization.
Number Base Converter
Convert numbers between binary, decimal, hexadecimal, octal, and any custom base — with bit grouping, signed integers, and step-by-step explanation.
Percent to EM Converter
Convert CSS percentage values to EM units. For font-size, 100% = 1em — a direct relationship. Supports bulk input and includes a reference table.
Percent to Point Converter
Convert CSS percentage values to typographic point (pt) units. Set the base font size, enter percent values, and get the pt equivalent.
Percent to PX Converter
Convert CSS percentage values to pixels. Set the parent element size, enter one or multiple percent values, and get the pixel equivalent with a full reference table.
Percent to REM Converter
Convert CSS percentage values to REM units. 100% = 1rem numerically. Supports bulk input and includes a reference table.
Point to EM Converter
Convert CSS/print point (pt) values to EM units. Set the parent font size, enter pt values, and get the EM equivalent. Useful for translating print sizes to screen CSS.
Point to Percent Converter
Convert typographic point (pt) values to CSS percentage units. Set the base font size, enter pt values, and get the percent equivalent.
Point to PX Converter
Convert CSS/print point (pt) values to pixels. Uses the standard 96dpi formula: 1pt = 96/72 px ≈ 1.3333px. Supports bulk input and includes a reference table.
Point to REM Converter
Convert CSS/print point (pt) values to REM units. Set the root font size, enter pt values, and get the REM equivalent. Useful for translating print sizes to screen CSS.
PX to EM Converter
Convert pixel values to EM units instantly. Set the parent element font size, enter one or multiple px values, and get the EM equivalent with a full reference table.
PX to Percent Converter
Convert pixel values to CSS percentage units. Set the parent element size, enter one or multiple px values, and get the percentage equivalent with a full reference table.
PX to Point Converter
Convert pixel values to CSS/print point (pt) units instantly. Uses the standard 96dpi formula: 1pt = 96/72 px. Supports bulk input and includes a reference table.
PX to REM Converter
Convert pixel values to REM units instantly. Set your base font size, enter one or multiple px values, and get the REM equivalent with a full reference table.
REM to Percent Converter
Convert CSS REM values to percentage. For root-relative sizing, 1rem = 100% of the root font size. Supports bulk input and includes a reference table.
REM to Point Converter
Convert CSS REM values to typographic point (pt) units. Set the root font size, enter REM values, and get the point equivalent. Useful for @media print stylesheets.
REM to PX Converter
Convert REM values to pixels instantly. Set your base font size, enter one or multiple REM values, and get the pixel equivalent with a full reference table.
SASS to SCSS Converter
Convert SASS indented syntax to SCSS brace syntax. Adds curly braces and semicolons, converts = and + shorthand to @mixin and @include.
SCSS to LESS Converter
Convert SCSS code to LESS syntax. Maps $variables to @variables, @mixin/@include to .mixin() syntax, and @extend to &:extend().
SCSS to SASS Converter
Convert SCSS brace syntax to SASS indented syntax. Removes braces and semicolons, converts @mixin/@include to = and + shorthand.
SCSS to Stylus Converter
Convert SCSS code to Stylus indented syntax. Removes braces and semicolons, converts $variables to bare assignments, @mixin/@include to function syntax.
Unix Timestamp Converter
Convert between Unix timestamps and human-readable dates across any timezone — with millisecond precision and real-time epoch display.
TSV to CSV Converter
Convert TSV (tab-separated values) to CSV online. Supports comma, semicolon, and pipe output delimiters with automatic quoting.
TSV to HTML Table Converter
Convert TSV (tab-separated values) to an HTML table. Supports header rows, bordered, striped, and responsive table styles.
TSV to JSON Converter
Convert TSV (tab-separated values) to JSON online. Supports header rows, array of objects or array of arrays output, and direct spreadsheet paste.
TSV to XML Converter
Convert TSV (tab-separated values) to XML. Each row becomes an XML element with configurable root, row, and column element names.
URL Encoder/Decoder
Encode and decode URL strings with special characters.
XML to CSV Converter
Convert XML to CSV online. Flattens repeated XML elements into rows and columns with configurable quoting and header options.
XML to JSON Converter
Parse and convert XML to clean JSON instantly — attributes, namespaces, and nested elements handled.
XML Validator
Validate XML syntax online. Shows valid/invalid status with exact error line and column, plus structure stats including root element name and element count.
YAML Beautifier
Format and prettify YAML with configurable indentation and optional key sorting. Validates YAML syntax instantly.
YAML Cheat Sheet
A complete YAML reference — scalars, sequences, mappings, multi-line strings, anchors, aliases, and gotchas. Quick lookup for developers working with YAML configs.
YAML to JSON Converter
Convert YAML to JSON and JSON to YAML — for config files, CI pipelines, and Kubernetes manifests.
YAML to XML Converter
Convert YAML to XML online. Supports nested objects, arrays, and custom root element names with optional XML declaration.
YAML Validator
Validate YAML syntax online. Shows valid/invalid status with exact error line and column, plus structure stats for valid documents.
Why Converter Tools Matter
Convert, format, encode, and clean common developer and content formats directly in the browser. Use these tools for JSON, Base64, URLs, CSV, YAML, XML, Markdown, HTML, timestamps, number bases, and other everyday conversion tasks.
The most common conversion tasks here fall into two clusters: data format work for developers — JSON, Base64, URL, YAML, XML, CSV — and document format work for writers and content teams — Markdown, HTML, and plain text. Both clusters benefit from being in the same place rather than scattered across separate utilities.
The developer cluster connects into the API and backend workflow through JSON formatters, Base64 tools, and timestamp converters. The creator cluster connects into text and SEO workflows through Markdown and HTML converters. Start with JSON Formatter if you are a developer, or Markdown to HTML if you are working on a content publishing workflow.
Converter Tool Collections
Grouped workflows that connect converter tools to adjacent tasks.
API & Backend Pack
Use free API and backend developer tools for JSON formatting, JWT decoding, SQL formatting, HTTP status codes, cron expressions, Base64, URL encoding, UUIDs, and webhooks.
Content Creator Kit
Plan, write, format, optimize, and publish content with free tools for word count, readability, markdown, meta tags, open graph previews, URL slugs, and content cleanup.
Converter Guides & Posts
In-depth guides and tips for getting the most out of converter tools.
Converter FAQ
Common questions about converter tools and how to use them.
What are the best free converter tools online?
JSON Formatter, Base64 Encoder/Decoder, URL Encoder/Decoder, CSV to JSON, Markdown to HTML, and Timestamp Converter are the most-used tools because they cover the most frequent tasks in API development, content publishing, and data cleanup workflows.
Can I convert CSV, YAML, or XML to JSON?
Yes. CSV to JSON, YAML to JSON, and XML to JSON all run in the browser and convert pasted or uploaded data instantly. These are useful when working with exports, legacy configs, or API data that arrives in a format your project does not natively support.
What is Base64 encoding used for?
Base64 encoding converts binary data into a text-safe format for transmission in URLs, JSON payloads, data URIs, and API tokens. It is not encryption — encoded data can be decoded by anyone. Use it for transport safety, not data security.
Can I convert Markdown to HTML online?
Yes. Markdown to HTML Converter transforms Markdown documents into clean, publish-ready HTML. Markdown Preview lets you see the rendered output live as you write. Both tools are useful for blog publishing, documentation, and CMS workflows.
What is the difference between URL encoding and Base64 encoding?
URL encoding makes strings safe for use in URLs by replacing special characters with percent-encoded sequences. Base64 encoding converts binary or text data into a compact ASCII representation for use in tokens, data URIs, and payloads. They solve different problems and should not be used interchangeably.
Can I convert Unix timestamps online?
Yes. Timestamp Converter converts Unix epoch values into human-readable dates and times, and converts dates back into epoch values. It is useful when reading API responses, debugging logs, or working with database fields that store time as integers.
Which converter tools are useful for developers?
JSON Formatter, Base64 Encoder/Decoder, URL Encoder/Decoder, CSV to JSON, YAML to JSON, and Timestamp Converter are the most frequently used by developers. They cover the common format tasks that come up during API work, debugging sessions, and backend data handling.