Tools

50 free, browser-based tools and calculators

Everything below runs entirely in your browser — no accounts, no tracking of what you type, and no invented data. Search or filter by category to find what you need.

Search tools

Start with these tools

Word & Character CounterCount words, characters, sentences, and paragraphs, and estimate reading time as you type.Text & Content

JSON Formatter & ValidatorFormat, minify, and validate JSON entirely in your browser — nothing is uploaded, and values are never silently changed.Developer & Data

Robots.txt GeneratorBuild a robots.txt file from structured user-agent, Allow, Disallow, and Sitemap rule groups, or validate one you already have — entirely locally, no live site is fetched.SEO & Webmaster

Marketing ROI CalculatorCalculate marketing ROI as a percentage return on spend, with a clear distinction from ROAS and from accounting profit.Marketing & Advertising

Image ResizerResize a JPEG, PNG, or WebP image to exact pixel dimensions, with aspect ratio lock and exact resize math — no accidental distortion.Image & Media

Color ConverterConvert colors between HEX, RGB, and HSL with a live preview.Design & Utility

50 tools

Word & Character CounterCount words, characters, sentences, and paragraphs, and estimate reading time as you type.Text & Content

Password Strength CheckerEstimate a password's entropy and check it against common-password patterns — entirely in your browser, nothing is sent anywhere.Design & Utility

Storage Unit ConverterConvert between bits, bytes, KB, MB, GB, TB, and PB using both decimal (1000-based) and binary (1024-based) definitions.Design & Utility

Color ConverterConvert colors between HEX, RGB, and HSL with a live preview.Design & Utility

Aspect Ratio CalculatorCalculate the simplified aspect ratio of any width and height, or solve for a missing dimension.Design & Utility

JSON Formatter & ValidatorFormat, minify, and validate JSON entirely in your browser — nothing is uploaded, and values are never silently changed.Developer & Data

Base64 Encode / DecodeEncode or decode text as Base64, UTF-8 safe — handles accented letters, emoji, and non-English text correctly.Developer & Data

UUID GeneratorGenerate one or many RFC-compatible UUID v4 values using your browser's secure random number generator.Developer & Data

Unix Timestamp ConverterConvert Unix timestamps (seconds or milliseconds) to UTC/local dates and back, with explicit timezone semantics.Developer & Data

UTM BuilderBuild a UTM-tagged URL that preserves existing query parameters and replaces old UTM values cleanly instead of duplicating them.Marketing & Advertising

Meta Tag Preview & GeneratorGenerate <title>, meta description, and canonical tags from a title, description, and URL, with a search-result-style preview.SEO & Webmaster

Regex TesterTest a JavaScript regular expression against sample text and see matches, positions, and capture groups — with a safety timeout against runaway patterns.Developer & Data

Text Case ConverterConvert text to UPPERCASE, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case, and kebab-case at once.Text & Content

HTTP Status Code ReferenceSearch and browse standard HTTP status codes by number, name, or meaning, with a concise practical note for each.Developer & Data

URL Encoder & DecoderEncode or decode text for use in a URL — separately for a single component or an entire structured URL — with malformed input clearly reported, never silently corrupted.Developer & Data

Hash GeneratorGenerate SHA-256, SHA-384, SHA-512, or SHA-1 hashes of text or a local file using your browser's built-in Web Crypto API.Developer & Data

JWT DecoderDecode a JWT's header and payload with readable timestamps for exp/nbf/iat — decoding only, never signature verification.Developer & Data

Text Diff CheckerCompare two blocks of text line by line and see exactly what was added, removed, or unchanged, with a summary count.Text & Content

CSV ↔ JSON ConverterConvert CSV to JSON or JSON to CSV with a real quoted-field-aware parser — never a naive comma split that breaks on real-world data.Developer & Data

Percentage CalculatorCalculate X% of Y, what percent X is of Y, percentage increase/decrease, or percentage difference — with the formula and substitution shown.Design & Utility

CPM CalculatorCalculate CPM, or solve for cost or impressions, from the other two — with the formula shown, not just a number.Marketing & Advertising

ROAS CalculatorCalculate return on ad spend from revenue and ad spend, with a plain-language interpretation and how it differs from ROI.Marketing & Advertising

CTR CalculatorCalculate click-through rate from clicks and impressions, with a link to Tecuy's real, sourced CTR benchmarks by channel.Marketing & Advertising

Robots.txt GeneratorBuild a robots.txt file from structured user-agent, Allow, Disallow, and Sitemap rule groups, or validate one you already have — entirely locally, no live site is fetched.SEO & Webmaster

Schema Markup GeneratorGenerate valid JSON-LD structured data for Article, Organization, WebSite, or BreadcrumbList — safely serialized, never fabricating a rating, review, or date you didn't provide.SEO & Webmaster

Open Graph GeneratorGenerate Open Graph and Twitter/X Card meta tags with an illustrative social-preview card — distinct from the Meta Tag Generator, which doesn't handle share images at all.SEO & Webmaster

Redirect Rule GeneratorGenerate exact-path 301/302 redirect rules for Apache (.htaccess) and Nginx from known-correct templates — never arbitrary, unvalidated server config.SEO & Webmaster

Slug GeneratorTurn a title into a clean URL slug — lowercase, separator of your choice, repeated separators collapsed — with an explicit, honest policy for non-English text.SEO & Webmaster

CPC CalculatorCalculate cost per click, or solve for cost or clicks from the other two — with the formula shown, not just a number.Marketing & Advertising

CPA CalculatorCalculate cost per acquisition/action, or solve for cost or conversions from the other two — with clear notes on how it differs from CPC and ROAS.Marketing & Advertising

Conversion Rate CalculatorCalculate conversion rate from conversions and a total you define — visitors, sessions, clicks, or leads — with an explicit note that these denominators aren't interchangeable.Marketing & Advertising

Engagement Rate CalculatorCalculate social engagement rate against followers, reach, or impressions — three genuinely different, clearly-labelled formulas, not one universal one.Marketing & Advertising

XML Sitemap GeneratorBuild a standards-compliant XML sitemap from a list of URLs you provide — no crawling, correctly XML-escaped, with the sitemaps.org URL-count limit enforced, not ignored.SEO & Webmaster

Hreflang Generator & ValidatorGenerate hreflang alternate-link tags for multi-language pages, with local validation for duplicates, code shape, and an x-default fallback.SEO & Webmaster

JSON-LD ValidatorCheck pasted JSON-LD (raw or script-tag-wrapped) for valid syntax and basic structure — never executed, never rendered as HTML.SEO & Webmaster

Robots.txt TesterTest whether a crawler would be allowed to fetch a given path under a robots.txt, using Google's own documented precedence algorithm.SEO & Webmaster

URL Parser & Query InspectorBreak a URL into protocol, host, path, query, and fragment, with every query parameter listed individually — duplicates preserved, never merged.Developer & Data

Cron Expression ParserParse a standard 5-field Unix cron expression into a plain-English description and its next execution times — correctly implements the day-of-month/day-of-week OR rule.Developer & Data

HTML Entity Encoder / DecoderEncode text for safe HTML use or decode HTML entities back to plain text — full numeric-entity support plus common named entities, no HTML parser involved.Developer & Data

Marketing ROI CalculatorCalculate marketing ROI as a percentage return on spend, with a clear distinction from ROAS and from accounting profit.Marketing & Advertising

CAC CalculatorCalculate customer acquisition cost from total acquisition spend and new customers, with guidance on what to include in that cost.Marketing & Advertising

Break-Even ROAS CalculatorCalculate the ROAS at which ad spend exactly offsets your gross margin — a profitability threshold, not a performance score.Marketing & Advertising

Campaign Budget CalculatorPlan a campaign budget from a target conversion count, using either CPC + conversion rate or a direct CPA — two clearly separated models.Marketing & Advertising

Image ResizerResize a JPEG, PNG, or WebP image to exact pixel dimensions, with aspect ratio lock and exact resize math — no accidental distortion.Image & Media

Image CompressorReduce a JPEG, PNG, or WebP file's size with an honest before/after comparison — including when a setting doesn't actually shrink it.Image & Media

Image Format ConverterConvert between JPEG, PNG, and WebP, with explicit transparency-to-background handling for JPEG and real output-format verification.Image & Media

Favicon & App Icon GeneratorGenerate 16×16 through 512×512 PNG favicon and app-icon sizes from one image — real PNG files, never mislabeled as a .ico.Image & Media

Image to Base64 ConverterConvert a JPEG, PNG, or WebP file into a ready-to-use Base64 Data URL, with a live preview and the exact size overhead shown.Image & Media

Base64 to Image ConverterDecode a base64 image Data URL back into a real, downloadable image file — JPEG/PNG/WebP only, never SVG or other executable content.Image & Media

Image Dimensions & File InspectorCheck a JPEG, PNG, or WebP file's real decoded dimensions, size, megapixels, and aspect ratio — not an EXIF viewer.Image & Media

Every tool above runs entirely in your browser — nothing you type or upload is sent to a server.