Guides & tutorials
Practical articles to help you get more from every tool.
Understanding JSON: A Practical Guide for Developers
What JSON is, how it is structured, and the common mistakes that break parsers — with examples you can fix in seconds.
Technical SEO Basics Every Site Needs in 2026
Meta tags, structured data, robots.txt and sitemaps — the technical foundations that help search engines understand your site.
The Complete Guide to Image Optimization
Choose the right format, compress without visible loss, and serve responsive images that keep your pages fast.
What Is Base64? How Encoding Works and Common Mistakes
What Base64 encoding actually does, where it is used, and the mistakes that cause broken or oversized output.
encodeURI vs encodeURIComponent: Which One to Use
How percent-encoding works, the difference between encoding a whole URL and a single component, and the mistakes that break links.
What Is a UUID? Version 4 vs Version 7 Explained
What a UUID looks like, why version 4 is the safe default, when version 7 is better, and best practices for IDs.
How SHA-256 and SHA-512 Hashes Work: Hashing vs Encryption
What a hash function does, how to choose between SHA-256 and SHA-512, and why hashing is not encryption.
What Is a JWT? Header, Payload and Signature Explained
A JSON Web Token has three parts. Learn what the header, payload and signature contain, how to read the claims, and why decoding is not verifying.
What Is HTML Encoding? Entities & Escaping Explained
Learn how HTML encoding works, why escaping prevents XSS and layout breaks, and how to encode and decode named, decimal, and hex entities.
Unix Time Explained: Seconds, Milliseconds and Time Zones
What a Unix timestamp is, how to tell seconds from milliseconds, how time zones come into it, and the values worth recognising.
Binary, Octal, Decimal and Hex: How Number Bases Work
How positional number bases work, why very large values need exact arithmetic, and the hex and binary values you meet every day.
Regex Basics: How Patterns, Flags and Character Classes Work
How a regular expression is built, what the flags change, and the character classes you will use most.
How to Convert JSON to CSV: Quoting and Nested Data
How JSON maps to CSV rows and columns, why correct quoting matters, and how to flatten nested data without losing it.
WCAG Color Contrast Explained: AA and AAA Ratios
What the WCAG contrast ratio measures, the 4.5:1 and 7:1 thresholds for AA and AAA, and how the rules change for large text and interface components.
Word and Character Limits That Matter for Writing and SEO
The length limits writers run into, from title tags and meta descriptions to social posts and essays, and how to use counts without writing to a number.
What Is Lorem Ipsum and When Should You Use It?
Where lorem ipsum comes from, why designers use placeholder text, and when real copy is the better choice.
What Is a URL Slug? SEO Best Practices for Clean URLs
What a URL slug is, why it matters for SEO, how to write a good one, and why changing a slug needs a redirect.
What Is a Text Diff? How Line-by-Line Comparison Works
What a diff actually compares, how to read added and removed lines, and practical uses from contracts to code.
Removing Duplicate Lines: What Counts as a Duplicate?
How duplicate lines creep into lists and exports, what counts as a duplicate once case and spacing are involved, and how to clean them up.
Alphabetical vs Natural Sort: How Line Sorting Works
The difference between alphabetical and natural sort order, why numbers in text sort oddly, and practical ways to order a list.
Reversed and Upside-Down Text: How It Works
What reversing text actually changes, how upside-down text is made from look-alike characters, and where each is useful.
How to Repeat Text 1,000 Times for WhatsApp (and Other Uses)
Repeat any text or emoji 10, 100, or 10,000 times online with custom newlines, spaces, and formatting. Perfect for messages and testing.
When to Use Base64 Images (and When Not To)
How to embed a Base64 image in HTML and CSS, when inlining helps, and the performance cost of doing it with large files.
How to Calculate Percentages: 3 Formulas with Examples
The three percentage formulas, worked examples, common mistakes, and the difference between percent and percentage points.
What Is BMI? Formula, Categories and Limitations
How body mass index is calculated, what the categories mean, a worked example, and the limits of BMI as a health measure.
How Age Is Calculated in Years, Months and Days
How an exact age is worked out from two dates, why months make it tricky, and how to count down to a birthday.
Counting Days Between Dates: Inclusive vs Exclusive
Should you count the first day, the last day or both? How inclusive and exclusive day counting differ, plus leap years and business days.
How to Calculate a Tip and Split the Bill
The simple maths behind a tip, a worked example for splitting a bill, and a rough guide to tipping customs around the world.
How to Calculate a Discount, Stacked Deals and Sales Tax
How percentage discounts are worked out, why two stacked discounts are less than their sum, and where tax fits in.
Unit Conversion Basics: Length, Weight, Temperature and Data
The conversions worth knowing by heart, why temperature needs a formula and not a single factor, and a quick worked example.
How QR Codes Work: Error Correction, Size and Scanning Tips
What a QR code can hold, how error correction trades size for reliability, and how to print codes that scan first time.
What Makes a Password Strong? Length, Randomness and Entropy
Password strength comes from length and randomness, measured in bits of entropy. How the numbers work, and the habits that keep accounts safe.
How Random Number Generators Work (and What Makes a Draw Fair)
The difference between Math.random and cryptographic randomness, how to draw numbers without repeats, and why random and fair are not the same thing.
HEX vs RGB vs HSL: Which Color Format to Use
HEX, RGB and HSL describe the same colours in three ways. Here is how each one works and when each is the easier choice in CSS and design tools.
How CSS Gradients Work: Angles, Color Stops and Examples
How linear and radial CSS gradients are built, what the angle really means, how colour stops are placed, and tips for gradients that look good.
CSS box-shadow Explained: Offset, Blur, Spread and Inset
How the CSS box-shadow property works, value by value, with tips for layered, realistic shadows.
CSS border-radius Explained: One, Two and Four Values
How the CSS border-radius property works and how its one-, two- and four-value shorthand maps to each corner.
How Loan EMI Is Calculated: The Formula Explained
How the EMI formula turns a loan amount, rate and term into a monthly payment, plus tips for borrowing at a lower cost.
How Compound Interest Works: Formula and Examples
How compound interest grows money, the formula behind it, how it compares with simple interest, and tips for getting more from it.
How to Pick a Color from an Image (Copy HEX & RGB Codes)
Pick exact HEX, RGB, and HSL color codes from any image. Extract dominant color palettes and copy color codes in 1 click.
Crop vs Resize vs Compress: What Cropping Does to an Image
What cropping changes, how it affects file size, and how it differs from resizing and compressing.
PNG vs JPG vs WebP: Which Image Format Should You Use?
When to pick PNG, JPG or WebP, what lossy and lossless really mean, and how to convert without throwing away quality.
Why Rotating an Image by 90 Degrees Loses No Quality
Why right-angle rotation is lossless, how it differs from rotating by an arbitrary angle, and how EXIF orientation causes sideways photos.
How Image Filters Work: Grayscale, Sepia, Contrast and Blur
What each image adjustment does, the order that gives the cleanest result, and three looks you can build from the sliders.
Favicon Sizes: Which Ones You Need and How to Add Them
Which favicon sizes browsers, iPhones and Android actually use, how to turn a logo into a clear 16px icon, and how to test it before launch.
How Text Summarizers Work: Extractive Summaries Explained
How an extractive summarizer scores sentences by word frequency, when that beats an AI rewrite, and how to get a better summary from it.
How Readability Scores Work and Which One to Report
How readability formulas turn sentence and word length into a score, how to improve yours, and which metric to quote to whom.
How Sentiment Analysis Works (and Where It Fails)
How word-list sentiment scoring works, where it gives a useful first read, and the cases, such as sarcasm, where it gets things wrong.
How Keyword Extraction Works and What to Do With the Results
How frequency-based keyword extraction finds the words and two-word phrases a text relies on, and practical ways to use the list for SEO and tagging.
How Browser Text to Speech Works and How to Use It Well
How your browser turns text into speech, where the voices come from, and how to get clearer, more natural results.
How to Choose Hashtags: Reach vs Relevance
How to turn a caption into useful hashtags, how many to use, and the trade-off between reach and relevance.
UTM Campaign Builder: Track Links With Confidence
Build correctly encoded UTM tracking URLs for your campaigns with ToolOrbit's free UTM Campaign Builder, all in your browser.
How to Write Title Tags and Meta Descriptions That Get Clicks
How Google builds a search snippet, the length limits to respect, and how to write titles and descriptions that earn the click.
What Is an XML Sitemap? Best Practices and Limits
What an XML sitemap does for search engines, which URLs belong in it, and when one sitemap file is not enough.
How to Write Numbers in Words: Rules and Examples
How numbers are spelled out in English: three-digit groups, scale words such as thousand and million, hyphens, and a worked example.
How Roman Numerals Work: Symbols, Rules and Examples
The seven Roman numeral symbols, the subtraction rule behind IV and IX, which forms are invalid, and a worked example.
How to Calculate Mean, Median and Mode (Worked Example)
How to work out the mean, median and mode by hand, with a worked example and guidance on which measure to report.
How to Tell if a Number Is Prime (with a Worked Example)
How primality testing by trial division works, a worked example with factors, and where prime numbers matter in practice.
How to Learn the Times Tables: Which Facts to Learn First
How a times table is built, a worked example, and an order for learning the multiplication facts that makes them quicker to remember.
How to Calculate Weighted GPA on the 4.0 Scale
The 4.0 grade point scale, how Honors and AP weighting changes the result, and a worked example.
How Simple Interest Works: Formula and Worked Example
The simple interest formula, a worked example, and when simple interest applies in place of compound interest.
How to Calculate Sales Tax (and Remove It From a Total)
How to add sales tax to a price, how to work backwards from a tax-inclusive total without the common mistake, and a worked example.
How to Calculate Profit Margin (with a Worked Example)
The formulas for profit margin and markup, a worked example, and how to price with the right number.
How Long Will It Take to Reach a Savings Goal?
How to work out the months needed to hit a savings target, a worked example, and why inflation moves the goal.
How to Calculate Your Break-Even Point (Formula + Example)
The break-even formula, the difference between fixed and variable costs, a worked example, and how to use the number to plan.
How to Calculate Markup and Set a Selling Price
How markup turns a cost into a selling price, why markup is not margin, and a worked example.
How to Calculate ROI and Annualized ROI
The ROI formula, why annualized ROI is the fair way to compare investments, a worked example, and how ROI differs from payback.
How to Merge PDF Files Online, Privately
Combine several PDFs into one document in your browser — reorder pages, no upload, no watermark.
How to Split a PDF or Extract Pages
Pull out a page range or split a PDF into single pages, all in your browser with no upload.
How to Convert Images to PDF (JPG & PNG)
Combine JPG and PNG images into a single PDF, one image per page, privately in your browser.
How to Rotate a PDF and Save It Permanently
Rotating in a PDF viewer usually changes only your view. Here is how to rotate the pages and save the file so it opens the right way up for everyone.
How to Delete Pages from a PDF (Free, No Upload)
A step-by-step way to delete single pages or page ranges from a PDF without installing software or uploading the file, and what to check afterwards.
How to Merge PDF Files Without Uploading Them Anywhere
Most "free" PDF mergers upload your documents to their servers. Here is why that matters, and how to combine PDFs entirely on your own device.
UTM Parameters Explained: How to Track Campaigns in GA4
What utm_source, utm_medium and utm_campaign actually mean, the naming conventions that keep reports clean, and the mistakes that ruin attribution.
Cron Every 5 Minutes — and the Rest of Cron Syntax, Explained
The five fields of a cron expression, the */5 pattern everyone searches for, and the day-of-week gotcha that surprises even experienced engineers.
Cron Expression Cheat Sheet — Copy-Paste Schedule Examples
Free cron expression cheat sheet with copy-paste examples for every 5 minutes, hourly, daily at midnight, weekdays only, and more.
Cron Every 10 Minutes — Syntax, Examples and Best Practices
Use the cron expression */10 * * * * to run jobs every 10 minutes, plus examples for common schedules and troubleshooting tips.
Your Photos Know Where You Live: How to Remove EXIF Data
Every phone photo embeds GPS coordinates, device details and timestamps. Here is what EXIF data reveals, who strips it for you, and how to remove it yourself.
Mean vs Median vs Mode: Which Average Should You Use?
They are all called "the average", but they answer different questions — and using the wrong one can badly mislead. Here is how to choose, with worked examples.
Flesch Reading Ease Score Explained: What Is a Good Score?
What the Flesch Reading Ease score measures, the number you should aim for, and practical ways to make writing easier to read.
Markup vs Margin: The Difference That Costs Businesses Money
Markup and margin use the same two numbers but mean very different things. Confusing them silently erodes your profit — here is how to keep them straight.
Why CSV Is Tricky to Parse: Delimiters, Quotes and Headers
Why CSV files are harder to read correctly than they look, how to choose the right JSON shape, and the mistakes to avoid.
YAML vs JSON: Differences That Matter When Converting
Why YAML is not just indented JSON, the types the two formats disagree on, and best practices for converting config files.
XML Formatting and Common XML Errors Explained
Why raw XML is hard to read, the errors that break sitemaps and feeds, when to minify, and how XML compares with JSON.
JSON String Escaping: What Needs Escaping and When
Which characters must be escaped inside a JSON string, when you need to do it, and how it differs from URL encoding.
Markdown Basics and Common Formatting Pitfalls
The Markdown syntax you will use most, the formatting mistakes that break a document, and the GitHub extras that change the output.
Why Minify CSS? What Is Safe to Remove and What Can Break
What CSS minification removes, when it is worth doing, which shortcuts are safe, and what a simple minifier can break.
How to Write SEO Meta Tags: Title, Description and Open Graph
Learn how to create effective title tags, meta descriptions, Open Graph and Twitter tags that improve search visibility and click-through rates.
How to Create robots.txt: Allow, Disallow and Sitemap Rules
Learn how to write a valid robots.txt file to control crawler access, protect private pages, and point search engines to your sitemap.
Keyword Density Checklist: Analyse and Improve Your SEO Copy
Understand how to measure keyword density, spot over-optimisation, and use phrase frequency to make content more readable and search-friendly.
How to Find Keywords in Any Text (Free Method)
Learn how to find keywords in text without expensive SEO tools. Extract 1-word terms, 2-word phrases, and density percentages in seconds.
Cron Every Hour, Day & Midnight: All Daily Schedules
Master standard daily cron schedules: cron every hour, every day at midnight, twice a day, and custom hourly intervals with copy-paste examples.
URL Encoding Explained: %20 vs +, Reserved Characters & Rules
Complete guide to percent encoding in URLs: learn when to use %20 vs +, how reserved characters like & and ? work, and how to avoid encoding bugs.
Percent Encoding Reference Table (Every Character)
Complete percent encoding ASCII reference table: quick lookup for spaces, slashes, ampersands, punctuation, and UTF-8 special characters in URLs.
CSS Border Radius: 15 Copy-Paste Examples
15 modern CSS border radius examples: rounded cards, pills, circle avatars, asymmetrical organic blobs, and fancy 8-value border radius shapes.
10 Common robots.txt Rules Explained (with Examples)
Master robots.txt syntax: understand User-agent, Disallow, Allow, Crawl-delay, and Sitemap directives with 10 real-world examples.
How Many Days Between Two Dates? (Calculator + Manual Method)
Calculate exact days between two dates: understand inclusive vs exclusive counting, leap years, working days, and manual calculation formulas.
Free Developer Tools Online: 2026 Developer Toolkit & Guides
Explore 30+ free browser-based developer tools: JSON formatters, Base64 converters, cron generators, regex testers, SQL formatters, and hash generators.
Watermarking a PDF: text stamps explained
When a CONFIDENTIAL or DRAFT stamp is worth adding, how to size and place it, and what a watermark can and cannot protect.
Page numbers in a PDF: placement, format and start values
How to number a PDF cleanly for reports, theses and filing — where to put the numbers, which format to pick, and how to start from any value.
How to create a reusable digital signature image
The difference between a signature image, an electronic signature and a legally binding one — and how to draw a clean PNG you can reuse.
Hourly to salary: the 2,080-hour rule and its limits
How yearly salary is derived from an hourly rate, when the calculation oversimplifies, and how to compare two job offers fairly.
VAT explained: adding and removing tax the right way
The formula for adding VAT to a net price and removing it from a gross price — plus the one mistake everyone makes in reverse.
GST rates in India: slabs, CGST and SGST explained
How India’s four GST slabs split between centre and state, when IGST applies, and how to add or remove GST from a price.
What is CAGR: annualized growth without the jargon
The compound annual growth rate formula, a worked example, and why it disagrees with simple averages when returns are volatile.
How to run a fair name draw in your classroom or giveaway
Why humans are bad at picking winners, what true randomness looks like, and how to run no-repeat draws for classes, raffles and standups.
Barcode formats compared: Code 128 vs EAN-13 vs UPC
Which linear barcode to use for retail, logistics and internal inventory — plus how check digits keep scanners honest.
What belongs on a freelance invoice (and what never does)
The mandatory fields, the tax handling, the numbering scheme, and the pieces of the invoice puzzle that only slow payment down.