Guides and how-tos
Practical, step-by-step guides for everyday jobs: getting an image under a size limit, fixing invalid JSON, working out a discount or writing a title tag that is not cut off. Each guide explains the idea, walks through a real example and links to the free tool that does the work.
SEO & Digital Marketing Tools
How to Check the Meta Tags of Any Web Page
Learn which meta tags matter for SEO and social sharing, how to view a page’s source, and how to audit title, description, canonical and robots tags in minutes.
Title Tag and Meta Description Length: How to Avoid Being Cut Off
Why search results cut titles and descriptions by pixel width, not characters, and how to write snippets that display in full on desktop and mobile.
How to Group Keywords into Clusters for a Content Plan
Turn a long keyword list into topic clusters, decide which keywords share one page and which need their own, and avoid two pages competing for the same search.
How to Create a Robots.txt File (with Examples)
What robots.txt does, safe example files for common sites, how to block AI crawlers or admin folders, and how to test a URL before you upload the file.
How to Create an XML Sitemap and Submit It to Google
Build a valid sitemap.xml from a list of URLs, choose honest lastmod dates, upload it to your site and submit it in Google Search Console and Bing.
How to Create UTM Links for Google Analytics
What utm_source, utm_medium and utm_campaign mean, a naming convention that keeps reports clean, and examples for email, WhatsApp, Facebook ads and QR codes.
What Is a Good Keyword Density for SEO?
Is there an ideal keyword density? What search engines look for instead, how to calculate density, and how to spot over-optimised text before you publish.
How to Plan Internal Links for SEO
Why internal links help pages get crawled and ranked, how to find orphan pages, choose good anchor text and plan links for a new or growing site.
Text & Writing Tools
Character and Word Limits for Social Media, SEO and Essays
Character and word limits for X posts, Instagram captions, LinkedIn, page titles and meta descriptions, plus how to count words and characters accurately.
How to Change Text to Uppercase, Lowercase or Title Case
Convert text to sentence case, Title Case, UPPERCASE or lowercase in one click, fix accidental caps lock, and learn the rules for camelCase and snake_case.
How to Remove Duplicate Lines from a List
Remove repeated emails, keywords, URLs or product codes from a list in seconds, choose case-sensitive matching, sort the result and see what was removed.
How to Find and Replace Text Online (Including Regex)
Replace every occurrence of a word or phrase at once, match whole words or case, delete text, and use simple regular expressions to reformat dates and lists.
What Is Lorem Ipsum and When Should You Use It?
Where lorem ipsum placeholder text comes from, when it helps designers and when real content is better, and how to generate paragraphs, lists or HTML.
How to Compare Two Texts and Find the Differences
Spot every word added, removed or changed between two versions of a document, contract, article or code file, and avoid false differences from line wrapping.
How to Write SEO-Friendly URL Slugs
What a URL slug is, rules for short readable slugs, hyphens vs underscores, stop words and dates, and how to change slugs without losing traffic.
How to Calculate Reading Time for a Blog Post or Speech
Work out “min read” labels and speech length from word count, with typical reading speeds of 200–300 wpm and speaking speeds of 120–170 wpm explained.
Image & File Tools
How to Compress an Image to 100KB (or Any Size Limit) Without Uploading It
Reduce a JPG, PNG or WebP photo to 100KB, 50KB or any size limit in your browser. Step-by-step settings that work, with no upload and no sign-up.
How to Resize an Image Without Losing Quality
Resize photos to exact pixel dimensions or by percentage without stretching or blurring, understand aspect ratio, and learn why enlarging cannot add detail.
How to Convert WebP to JPG (and PNG to WebP)
Convert WebP images to JPG for apps that reject WebP, or PNG to WebP for a faster website. Choose quality, handle transparency and convert files in bulk.
How to Crop a Photo to a Square, 4:5 or 16:9
Crop photos to exact aspect ratios for profile pictures, Instagram posts, YouTube thumbnails and link previews, and rotate sideways photos before cropping.
How to Find the HEX Code of a Colour in an Image
Pick any colour from a photo, logo or screenshot and get its HEX, RGB and HSL values, extract a palette, and understand what each colour code means.
How to Create a QR Code for a Link, Wi-Fi or Contact Card
Make a free QR code for a website, Wi-Fi password, phone number, text message, email or contact card that never expires, and print it so it scans reliably.
How to Merge PDF Files Without Uploading Them
Combine PDFs into one document in any order, include only certain pages, or split a PDF into separate files, all in your browser so private files stay private.
How to Convert a PDF to JPG or PNG Images
Turn PDF pages into JPG, PNG or WebP images for forms, slides and social posts. Choose pages and resolution, and pick the right DPI for screen or print.
Online Calculators & Converters
How to Calculate Percentages: Formulas and Examples
Simple formulas for percentage of a number, what percent one number is of another, percentage increase and decrease, and reversing a percentage, with examples.
How to Calculate a Discount and the Final Sale Price
Work out the sale price after a percentage or fixed discount, what “extra 10% off” really saves, and how sales tax changes the final price, with examples.
Margin vs Markup: What’s the Difference and How to Calculate Both
Profit margin and markup explained with formulas and examples, a conversion table, and how to set a selling price that hits your target margin after fees.
How to Calculate Exact Age in Years, Months and Days
Work out an exact age in years, months and days from a date of birth, find age on a specific date for applications and exams, and handle 29 February birthdays.
How to Count Days Between Two Dates (Including Working Days)
Count calendar or working days between two dates, decide whether to include the end date, skip public holidays, and add business days to find a deadline.
Common Unit Conversions: A Quick Reference
Exact conversion factors for inches, feet, miles, pounds, kilograms, litres, gallons and temperature, plus GB vs GiB and how to convert anything else.
How Is BMI Calculated? Formula, Categories and Limits
The BMI formula in metric and imperial units, the standard adult categories, a worked example, and what BMI does and does not tell you about health.
How Compound Interest Works (With Examples)
The compound interest formula explained, how compounding frequency and monthly deposits change the result, the rule of 72, and worked examples you can check.
Developer Tools
How to Fix Invalid JSON: The 7 Most Common Errors
Why JSON fails to parse — trailing commas, single quotes, unquoted keys, comments and more — with before-and-after fixes and how to find the exact error line.
What Is Base64 Encoding and When Should You Use It?
How Base64 turns binary data into text, why it makes files a third larger, URL-safe Base64, data URIs, and why Base64 is not encryption, with examples.
What Is URL Encoding (Percent-Encoding)?
Why spaces become %20 in links, which characters must be encoded, component vs full-URL encoding, + versus %20, and how to fix double-encoded URLs.
How to Verify a File Checksum (MD5, SHA-256)
Check that a download is complete and unaltered by comparing its SHA-256 or MD5 checksum, in the browser or with Windows, macOS and Linux commands.
UUID v4 vs v7: Which Should You Use?
What a UUID is, how random version 4 and time-ordered version 7 differ, why v7 suits database primary keys, and how to generate and inspect UUIDs.
Regex Basics for Beginners: A Practical Guide
Learn regular expressions step by step: character classes, quantifiers, anchors, groups and flags, with tested patterns for emails, dates, numbers and more.
How to Minify CSS, JavaScript and HTML
What minification removes, how much it saves, how it differs from gzip compression, and a safe workflow to minify code for a faster website without breaking it.
How to Create a Strong Password (and Remember It)
What makes a password strong, why length beats complexity, how entropy is measured in bits, and practical habits: password managers, passphrases and 2FA.