100% In-Browser & Private

Email Subject Line Length & Preview Checker

Client-Side Sandbox
100% In-Browser Privacy All computations and file processing run strictly in your browser. Zero server data uploads.

Optimize email subject lines for mobile and desktop inboxes (Gmail, Outlook, iPhone) with live previews.

Inbox Visibility & Truncation Tester

Test email subject line lengths against mobile and desktop inbox cut-off thresholds (Gmail, iPhone Mail, Outlook).

Character Count 0
Word Count 0
Mobile Friendly (≤ 41 Chars) -
Desktop Friendly (≤ 60 Chars) -

Simulated Inbox Previews:

iPhone Mail (~38 chars):
Gmail Desktop (~60 chars):
Standards Verified
Deterministic & Accurate Output Tested against official specifications for reliable, reproducible calculation results.

How to Use This Tool

  1. Type or paste your text directly into the editor workspace above.
  2. Select formatting options, case conversion, or analytical filters.
  3. View real-time statistics or transformed text instantly, then click Copy or Download.

Supported Formats, Boundaries & Privacy

Inputs & Boundaries: Supports all standard UTF-8 text strings, ASCII, and Unicode symbols directly within browser memory.

Local Client-Side Processing: Tool computations and file operations execute 100% locally within your browser sandbox via JavaScript and HTML5 Web APIs. Your input values, uploaded files, and computed results are never transmitted to our web servers. General site access, analytics, and advertising cookies are managed transparently under our Privacy Policy and Cookie Policy.

Keyboard Shortcut /
Press / Anytime to Quick-Search Jump directly to any tool across all categories with instant keyboard navigation.

Related Tools in Text & Writing Tools

Word & Character Counter

Count words, characters (with and without spaces), sentences, paragraphs, and estimated reading/speaking time in real time.

Case Converter

Convert text to UPPERCASE, lowercase, Title Case, Sentence case, alternating cAsE, and camelCase with Unicode support.

Text Cleaner

Strip extra whitespace, normalize Windows/Unix/Mac line endings, remove empty lines, and trim text safely.

Lorem Ipsum Generator

Generate customizable placeholder dummy text by words, sentences, or paragraphs with optional HTML markup.

Spell & Typo Checker

Inspect spelling errors, duplicate words, and grammatical typos client-side with complete privacy.

Text Diff & Comparison Checker

Compare two text versions side-by-side or line-by-line to identify additions, removals, and revisions.

Duplicate Line Remover

Remove duplicate lines from lists, log files, or text blocks with case sensitivity and sorting controls.

Find and Replace Tool

Search and replace words, phrases, or regex patterns in large documents with occurrence count tracking.

Reading & Speaking Time Calculator

Calculate estimated silent reading time and spoken presentation duration for speeches, essays, and blog articles.

Text to URL Slug Converter

Convert article headlines and titles into clean, SEO-friendly URL slugs with stop-word stripping.

Markdown Live Previewer & Editor

Edit Markdown in real-time with instant client-side HTML preview rendering and copy capabilities.

Sentence Counter & Sentence Case Converter

Analyze sentence counts, average sentence length, and convert text to proper grammatical sentence case.

Professional HTML Email Signature Generator

Design clean, responsive HTML email signatures compatible with Gmail, Apple Mail, and Outlook.

Email Address Syntax & Format Validator

Verify email addresses against RFC 5322 syntax standards, detect disposable email domains, and validate MX readiness.

Text to Binary & Binary to Text Converter

Encode ASCII and UTF-8 strings into 8-bit binary numbers, or decode binary streams back into readable text.

Text to Hexadecimal & Hex to Text Converter

Convert plain text into hexadecimal strings with configurable delimiters, or decode hex bytes into UTF-8 text.

Word Frequency & Keyword Density Counter

Analyze word occurrences, keyword density percentages, and recurring phrases with stop-word filtering.

Reading Level & Flesch-Kincaid Analyzer

Calculate Flesch Reading Ease, Flesch-Kincaid Grade Level, and estimated reading time for any prose.

Academic Citation Formatter (APA, MLA, Chicago, Harvard)

Generate properly structured bibliographic citations in APA 7, MLA 9, Chicago 17, and Harvard styles.