Guides written against the tools themselves: the exact pixel dimensions that hit a 100 KB limit, the passport photo sizes each country demands, the PDF settings that survive a 2 MB portal, and the JSON errors that break API calls. Every procedure runs in your browser, so nothing you test is uploaded anywhere.
A tested method for hitting 100 KB, 50 KB, 20 KB or 500 KB exactly: dimension math, quality steps, and the formats that shrink best. Works on phone and desktop, no upload required.
Updated 8 October 2026 · 1307 words
Exact photo sizes for US, UK, Schengen, India, Canada, Australia and China applications — millimetres, pixels, KB limits, background and head-height rules, plus how to prepare a compliant file.
Updated 8 October 2026 · 1214 words
The numbers that decide whether a printed QR scans: module size, quiet zone, error-correction level (L/M/Q/H), matte vs gloss, print DPI and a real test routine. Generate a print-ready code free, in the browser.
Updated 8 October 2026 · 1115 words
What 2x/4x/8x interpolation really does, why enlarging cannot invent captured detail, smooth versus nearest-neighbour, and when upscaling helps versus when to leave the image alone.
Updated 9 October 2026 · 880 words
WebP is 25-35% smaller and adds transparency and animation, but JPEG still wins on reach. When each fits, lossy versus lossless, and how compatibility and the quality slider change the choice.
Updated 9 October 2026 · 928 words
You can grab a video's preview image, but usage rights are separate from the download button. Ownership, fair use, embedding versus re-hosting, and the safe rules - plus how the downloader actually works.
Updated 9 October 2026 · 991 words
Open iPhone HEIC photos on a PC: use a browser HEIC converter that decodes locally, or install the HEVC/HEIF extensions. What HEIC is, why Windows struggles, and when to convert.
Updated 9 October 2026 · 1075 words
Get scanned documents, CVs and certificates under any portal limit with real downsampling settings — plus why your PDF is huge, why merging adds pages, and how to keep text selectable.
Updated 8 October 2026 · 1096 words
Scan pages, join them into one PDF and email it - all in the browser on your phone. Real page-count and size limits, the scan-then-merge workflow, and how to stay under a 2 MB portal cap without a desktop or an app.
Updated 8 October 2026 · 1176 words
Digital PDFs carry a real text layer and convert cleanly; scanned PDFs need OCR with imperfect results. What a converter can and cannot give you, and how to get a good edit.
Updated 9 October 2026 · 920 words
Turn camera photos of pages into a proper PDF: shoot pages that scan well, drag to reorder, set page size, margins and quality, merge batches, and keep everything on-device.
Updated 9 October 2026 · 909 words
Line and column errors explained: trailing commas, single quotes, unquoted keys, escaping, arrays versus objects, and the XML-to-JSON gotchas that break integrations. Paste and validate instantly.
Updated 8 October 2026 · 1170 words
Why base64 costs about 33% more bytes, how data URIs save or add requests, the HTTP/2 reality, cacheability trade-offs, and inline SVG vs bitmap. Encode and decode a data URI free, in your browser.
Updated 8 October 2026 · 847 words
What LCP, INP and CLS actually measure, lab vs field data, the biggest real fixes - image sizing, render-blocking JS/CSS, caching - and how to check server latency. Be honest that a quick checker is not PageSpeed Insights.
Updated 8 October 2026 · 999 words
A plain-language tour of regex syntax, the JavaScript flags (g, i, m, s, u), capture groups, the greedy-vs-lazy and engine gotchas, and how to test a pattern safely before you ship it.
Updated 9 October 2026 · 911 words
The traps that silently corrupt CSV data - quoted fields, embedded commas and newlines, header-vs-array shape, auto-typed numbers and BOM - and how to convert to JSON safely.
Updated 9 October 2026 · 983 words
XML and JSON are not equivalent trees. How attributes, repeated elements, mixed content, CDATA and namespaces map across - and where silent data loss and array-vs-object ambiguity bite.
Updated 9 October 2026 · 953 words
HTML minification shrinks bytes, compression shrinks transfer, and a CDN or cache cuts latency and rework. What each layer actually changes and the order to apply them.
Updated 9 October 2026 · 907 words
A SQL beautifier only reflows text - it cannot prove a query is correct. How to format for review, pick a house style, and combine it with real validation and EXPLAIN.
Updated 9 October 2026 · 830 words
What cryptographic hashes are, why MD5 is broken and SHA-256 is not, why both are wrong for passwords, and why base64 is not hashing at all.
Updated 9 October 2026 · 943 words
Percent-encoding, the RFC 3986 reserved vs unreserved split, the difference between encoding one parameter value and a whole URL, and the double-encoding traps that break requests.
Updated 9 October 2026 · 981 words
A favicon is not one file. Which sizes serve which surfaces - tab, apple-touch, PWA 192/512, legacy ICO - what SVG can and cannot replace, and what a generator can really output.
Updated 9 October 2026 · 983 words
Epoch time is seconds since 1970 UTC ignoring leap seconds. Why 32-bit signed counters roll over in 2038, the seconds-versus-milliseconds bug, and always storing UTC.
Updated 9 October 2026 · 940 words
Random UUID v4 versus sequential integer IDs: index locality, key size, global uniqueness, enumeration risk, and the time-ordered middle ground (UUIDv7/Snowflake/ULID).
Updated 9 October 2026 · 1016 words
How many bits a password really has, why length beats symbols, honest offline-crack-time maths, and where a password manager and 2FA matter. Generate a strong random password in your browser with nothing sent anywhere.
Updated 8 October 2026 · 839 words
What a GDPR privacy policy must disclose, the many obligations that live outside the document, how CCPA differs, and how to use a policy generator without mistaking a draft for compliance.
Updated 9 October 2026 · 1014 words
Exactly what a word counter counts, whether the bibliography and headings are included, why 250 words is 250 words, and how to trim to the limit without breaking citations. Count free, in your browser, with no upload.
Updated 8 October 2026 · 946 words
Why a browser plagiarism checker cannot compare your text to the internet, what matched-source detection actually needs, how to paraphrase legitimately, and how to use originality tools without fooling yourself.
Updated 9 October 2026 · 966 words
Browser TTS speaks text with the voices already on the device. Who it helps (low vision, dyslexia, proofreading), where it falls short, and why it complements rather than replaces accessible design.
Updated 9 October 2026 · 914 words
The real EMI formula, why a longer tenure lowers the payment but raises total interest, the 28/36 affordability rule, part-payment and balance-transfer maths - all worked through. Calculate free, in your browser.
Updated 8 October 2026 · 877 words
BMI is weight over height squared - a cheap screening proxy, not body fat or a diagnosis. Where it misleads: athletes, children, the elderly, pregnancy, and different ethnicities.
Updated 9 October 2026 · 828 words
Age 'as of' a reference date, completed years, leap-day (Feb 29) birthdays, and unambiguous date formats for admissions, exams, visas and benefits paperwork.
Updated 9 October 2026 · 946 words
Working-day math for contracts and delivery SLAs: exclude weekends, remember holidays are not built in, and handle the inclusive-versus-exclusive start-date off-by-one errors.
Updated 9 October 2026 · 910 words
The elements almost every invoice carries versus the jurisdiction-specific extras - tax/GST/VAT number, tax breakdown, e-invoicing, sequential numbering. A template is not tax advice.
Updated 9 October 2026 · 959 words
The exact factors for length, weight and temperature, the tonne vs ton vs metric-cwt trap, rounding rules for construction and cooking, and how to convert without introducing error. Convert free, in your browser.
Updated 8 October 2026 · 798 words
A practical, honest walkthrough: build an XML sitemap, host it, reference it in robots.txt, and submit it in Google Search Console and Bing - plus why a sitemap is a hint, not a guarantee of indexing.
Updated 9 October 2026 · 1064 words
A clear, tested reference for every robots.txt line - how matching works, the $ and * rules, crawl-delay reality, and the mistakes that silently block the wrong things.
Updated 9 October 2026 · 1054 words
There is no official character limit. Here is how Google actually truncates by pixel width, the ranges that usually survive on desktop and mobile, and how to write a description that gets shown instead of rewritten.
Updated 9 October 2026 · 1066 words
Who the AI bots are (GPTBot, ClaudeBot, PerplexityBot, Google-Extended and more), how to allow or block each in robots.txt, and an honest take on what llms.txt does and does not do.
Updated 9 October 2026 · 1060 words
Domain Authority is a Moz prediction, not a Google metric. What DA and PA really mean, why they differ between tools, how to use them honestly, and how our checker fetches them.
Updated 9 October 2026 · 1030 words
Why 404s and dead outbound links leak value, the HTTP codes behind them, a practical one-page check workflow, and how to fix each failure - using a browser-based link checker.
Updated 9 October 2026 · 995 words
Crawling, indexing and ranking are three separate stages. What crawled-but-not-indexed really means, which signals let a page be indexed, and how to verify status honestly in Search Console.
Updated 9 October 2026 · 983 words
What keyword density actually measures, why chasing a target percentage is a myth, when the number is a useful red flag, and how to use a density checker without stuffing.
Updated 9 October 2026 · 881 words
What utm_source, medium, campaign, term and content actually capture, the rules for a consistent lowercase naming scheme, a copy-paste template, and the traps that wreck attribution.
Updated 9 October 2026 · 902 words
A plain-language map of 200, 301, 302, 404, 410, 403 and 5xx codes, what each does to your SEO, and how to read a URL's real status without guessing.
Updated 9 October 2026 · 938 words
All guides are backed by free tools that need no signup: image compressor, PDF compressor, JSON formatter and 97 more. See the complete list of tools.
