Tools
58 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 type, task or category to find what you need.
Type
Task
Category
58 tools
58 tools foundSEO & Webmaster 11
Robots.txt, structured data, redirects, and other on-site technical SEO utilities.
- CalculatorCore Web Vitals Assessment CalculatorRate LCP, INP and CLS (plus FCP and TTFB) against Google's thresholds, working out the 75th percentile from raw field measurements if you paste them.LCP, INP and CLS ratings · p75 from raw samples
- UtilityHreflang Generator & ValidatorGenerate hreflang alternate-link tags for multi-language pages, with local validation for duplicates, code shape, and an x-default fallback.Alternate-link tags · x-default and duplicate checks
- UtilityJSON-LD ValidatorCheck pasted JSON-LD (raw or script-tag-wrapped) for valid syntax and basic structure — never executed, never rendered as HTML.Syntax and structure check · Never executed
- UtilityMeta Tag Preview & GeneratorGenerate <title>, meta description, and canonical tags from a title, description, and URL, with a search-result-style preview.Title, description, canonical · Search result preview
- UtilityOpen 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.Open Graph and X cards · Social preview
- UtilityRedirect Rule GeneratorGenerate 301/302 redirect rules for Apache (.htaccess) and Nginx from fixed templates, with validated paths — never arbitrary, unvalidated server config.Apache and Nginx · 301 and 302 rules
- UtilityRobots.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.User-agent rule groups · Validate an existing file
- UtilityRobots.txt TesterTest whether a crawler would be allowed to fetch a given path under a robots.txt, using Google's own documented precedence algorithm.Allowed or blocked · Google's precedence rules
- UtilitySchema 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.Article, Organization, WebSite · Valid JSON-LD
- UtilitySlug 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.Clean URL slugs · Choose a separator
- UtilityXML 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.From your URL list · URL-count limit enforced
Developer & Data 14
JSON, encoding, hashing, regex, and other everyday developer utilities.
- UtilityBase64 Encode / DecodeEncode or decode text as Base64, UTF-8 safe — handles accented letters, emoji, and non-English text correctly.Encode and decode · UTF-8 safe
- UtilityCron 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.Plain-English schedule · Next run times
- UtilityCSV ↔ 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.CSV to JSON and back · Quoted fields handled
- UtilityHash 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.SHA-256, 384, 512, SHA-1 · Text or local files
- UtilityHTML 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.Encode or decode entities · Numeric and named
- UtilityHTTP Status Code ReferenceSearch and browse standard HTTP status codes by number, name, or meaning, with a concise practical note for each.Search by code or name · Practical notes
- UtilityJSON Formatter & ValidatorFormat, minify, and validate JSON entirely in your browser — nothing is uploaded, and values are never silently changed.Format and minify · Validation errors
- UtilityJWT DecoderDecode a JWT's header and payload with readable timestamps for exp/nbf/iat — decoding only, never signature verification.Header and payload · Readable expiry times
- UtilityRegex TesterTest a JavaScript regular expression against sample text and see matches, positions, and capture groups — with a safety timeout against runaway patterns.Matches and capture groups · Runaway-pattern timeout
- CalculatorSubnet Calculator (IPv4 & IPv6)Calculate the network, host range, mask and address count for any IPv4 or IPv6 CIDR block, and split it into smaller subnets.IPv4 and IPv6 · Split into subnets
- UtilityUnix Timestamp ConverterConvert Unix timestamps (seconds or milliseconds) to UTC/local dates and back, with explicit timezone semantics.Seconds or milliseconds · UTC and local time
- UtilityURL 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.Component or full URL · Malformed input reported
- UtilityURL Parser & Query InspectorBreak a URL into protocol, host, path, query, and fragment, with every query parameter listed individually — duplicates preserved, never merged.Protocol, host, path, query · Every parameter listed
- UtilityUUID GeneratorGenerate one or many RFC-compatible UUID v4 values using your browser's secure random number generator.UUID v4 · Bulk generation
Marketing & Advertising 17
Ad-spend, conversion, unit-economics and campaign-tracking calculators.
- CalculatorA/B Test Significance & Sample Size CalculatorCheck whether an A/B test result is statistically significant, see the confidence interval for the difference, and plan how many visitors a test needs.p-value and interval · Sample size planner
- CalculatorBreak-Even ROAS CalculatorCalculate the ROAS at which ad spend exactly offsets your gross margin — a profitability threshold, not a performance score.Profitability threshold · From gross margin
- CalculatorCAC CalculatorCalculate customer acquisition cost from total acquisition spend and new customers, with guidance on what to include in that cost.Cost per new customer · What to include
- CalculatorCAGR & Compound Growth Rate CalculatorCalculate compound annual (CAGR), quarterly or monthly growth between two values, project a value forward at a fixed rate, or find how long a target takes.CAGR and monthly rate · Projection and time to target
- CalculatorCampaign Budget CalculatorPlan a campaign budget from a target conversion count, using either CPC + conversion rate or a direct CPA — two clearly separated models.From a conversion target · CPC or CPA model
- CalculatorChurn Rate & Revenue Retention (GRR, NRR) CalculatorCalculate customer churn, gross and net revenue retention and net MRR churn from one period's customer counts and MRR movements, with the MRR bridge.Churn, GRR and NRR · MRR bridge
- CalculatorConversion 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.Any denominator · Visitors, sessions or leads
- CalculatorCPA 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.Cost per acquisition · CPA vs CPC and ROAS
- CalculatorCPC CalculatorCalculate cost per click, or solve for cost or clicks from the other two — with the formula shown, not just a number.Cost per click · Solve for cost or clicks
- CalculatorCPM CalculatorCalculate CPM, or solve for cost or impressions, from the other two — with the formula shown, not just a number.Cost per thousand · Solve for cost or impressions
- CalculatorCTR CalculatorCalculate click-through rate from clicks and impressions, with a link to Tecuy's real, sourced CTR benchmarks by channel.Click-through rate · Links to CTR benchmarks
- CalculatorCustomer Lifetime Value (LTV) & LTV:CAC CalculatorCalculate customer lifetime value from churn, expected lifetime or repeat purchases, then compare it with CAC and see your payback period.Lifetime value · LTV:CAC and payback
- CalculatorEngagement Rate CalculatorCalculate social engagement rate against followers, reach, or impressions — three genuinely different, clearly-labelled formulas, not one universal one.By followers, reach or impressions · Three labelled formulas
- CalculatorMarketing ROI CalculatorCalculate marketing ROI as a percentage return on spend, with a clear distinction from ROAS and from accounting profit.ROI percentage · ROI vs ROAS explained
- CalculatorProfit Margin & Markup CalculatorCalculate gross margin, markup and profit from cost and price, or find the selling price for a target margin or markup.Margin and markup · Price for a target margin
- CalculatorROAS CalculatorCalculate return on ad spend from revenue and ad spend, with a plain-language interpretation and how it differs from ROI.Return on ad spend · ROAS vs ROI explained
- UtilityUTM BuilderBuild a UTM-tagged URL that preserves existing query parameters and replaces old UTM values cleanly instead of duplicating them.Campaign-tagged URLs · Keeps existing parameters
Image & Media 7
Resize, compress, convert, and inspect images entirely in your browser.
- UtilityBase64 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.Data URL to file · JPEG, PNG and WebP
- UtilityFavicon & 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.16 to 512 px icons · Real PNG files
- UtilityImage CompressorReduce a JPEG, PNG, or WebP file's size with an honest before/after comparison — including when a setting doesn't actually shrink it.JPEG, PNG and WebP · Before and after size
- UtilityImage Dimensions & File InspectorCheck a JPEG, PNG, or WebP file's real decoded dimensions, size, megapixels, and aspect ratio — not an EXIF viewer.Real dimensions and size · Megapixels and ratio
- UtilityImage Format ConverterConvert between JPEG, PNG, and WebP, with explicit transparency-to-background handling for JPEG and real output-format verification.JPEG, PNG and WebP · Transparency handling
- UtilityImage ResizerResize a JPEG, PNG, or WebP image to exact pixel dimensions, with aspect ratio lock and exact resize math — no accidental distortion.Exact pixel size · Aspect ratio lock
- UtilityImage 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.Data URL output · Size overhead shown
Text & Content 4
Word counts, text comparison, and case conversion.
- UtilityKeyword Density & Phrase Frequency CheckerCount how often words and two- or three-word phrases appear in a text, with density, a focus-keyword check and CSV export — no ideal-density claims.Words and 2–3 word phrases · Focus keyword check
- UtilityText Case ConverterConvert text to UPPERCASE, lowercase, Title Case, Sentence case, camelCase, PascalCase, snake_case, and kebab-case at once.Eight cases at once · camelCase to kebab-case
- UtilityText Diff CheckerCompare two blocks of text line by line and see exactly what was added, removed, or unchanged, with a summary count.Line-by-line changes · Added and removed counts
- UtilityWord & Character CounterCount words, characters, sentences, and paragraphs, and estimate reading time as you type.Words, characters, sentences · Reading time
Design & Utility 5
Color conversion and other general-purpose calculators.
- CalculatorAspect Ratio CalculatorCalculate the simplified aspect ratio of any width and height, or solve for a missing dimension.Simplified ratio · Solve a missing side
- UtilityColor ConverterConvert colors between HEX, RGB, and HSL with a live preview.HEX, RGB and HSL · Live preview
- UtilityPassword Strength CheckerEstimate a password's entropy and check it against common-password patterns — entirely in your browser, nothing is sent anywhere.Entropy estimate · Common-pattern check
- CalculatorPercentage CalculatorCalculate X% of Y, what percent X is of Y, percentage increase/decrease, or percentage difference — with the formula and substitution shown.Four percentage formulas · Working shown
- UtilityStorage Unit ConverterConvert between bits, bytes, KB, MB, GB, TB, and PB using both decimal (1000-based) and binary (1024-based) definitions.Bits to petabytes · Decimal and binary units
Every tool above runs entirely in your browser — nothing you type or upload is sent to a server.