Guides
Practical answers to everyday questions about images, text, numbers and data. Each of our 22 guides explains the idea, works through real examples, and links to the free tool that does the job in your browser.
🖼️ Image guides
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Image Sizes for Every Platform: Social Media, Email and WebsitesPixel sizes and aspect ratios for every major platform, with a worked example. Tool: Image Resizer · Published Sep 29, 2026
🗜️How to Reduce a Photo to Under 100 KB or 200 KBMeasured file sizes at different dimensions and quality levels, and a method for upload forms. Tool: Image Resizer · Updated Oct 4, 2026
📸HEIC vs JPG: Why iPhone Photos Get Rejected and How to Fix ItWhy forms and Windows reject iPhone photos, and three ways to fix it. Tool: HEIC to JPG · Published Sep 30, 2026
🧩JPG vs PNG vs WebP: Which Image Format Should You Use?Which format to use for photos, graphics and websites, with measured sizes. Tool: JPG to WebP · Published Sep 30, 2026
🖼️Why You Can't Open a WebP Image (and How to Convert It)Why saved images end up as WebP, and how to open or convert them. Tool: WebP to JPG · Published Sep 30, 2026
📏Aspect Ratio Explained: Resize Without Stretching or CroppingThe formula for the missing side, common ratios, and how to change shape safely. Tool: Image Resizer · Published Sep 30, 2026
🎨HEX, RGB and HSL Color Codes Explained with ExamplesHow the three color formats work, with conversions and a reference table. Tool: Color Picker · Published Sep 30, 2026
👁️Accessible Text Colors: Contrast Ratios ExplainedWCAG thresholds and measured ratios for common color pairs. Tool: Color Picker · Published Sep 30, 2026
⚡How to Make Images Load Faster on Your WebsiteMeasured savings from resizing and WebP, srcset and lazy loading. Tool: Image Resizer · Published Oct 3, 2026
🪪How to Resize a Photo for Online ApplicationsDimensions, KB ranges, mm-to-pixel conversion and rejection fixes. Tool: Image Resizer · Published Oct 3, 2026
🧮 Calculation and date guides
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Percentage Formulas: Increase, Decrease, Discounts and Percentage PointsThe three formulas, stacked discounts, VAT and percentage points. Tool: Percentage Calculator · Published Sep 30, 2026
🎂How to Calculate Your Exact Age in Years, Months and DaysThe method, with month-end and February 29 birthdays explained. Tool: Age Calculator · Published Sep 30, 2026
📅Counting Days Between Dates: Inclusive, Exclusive and DeadlinesInclusive vs exclusive counting, deadlines, leap years and business days. Tool: Days Between Dates · Updated Oct 28, 2026
🇯🇴Jordan Public Holidays and Working Days in 2026 and 20272026 holidays, expected 2027 Eid dates and working days per month. Tool: Days Between Dates · Published Oct 27, 2026
🧾How to Write an Amount in Words on a ChequeFilling in a cheque, cents and fils, and what happens when words and figures differ. Tool: Amount in Words · Published Nov 2, 2026
💵How Much to Tip and How to Split a Bill FairlyTipping customs by country, before or after tax, and fair ways to split. Tool: Tip Calculator · Published Sep 30, 2026
📝 Text guides
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Word Count Limits: Essays, Abstracts, Cover Letters and MoreTypical limits, how words are counted, reading time, and how to cut. Tool: Word Counter · Published Sep 30, 2026
🔤Character Limits for Social Posts, SMS and SEO TitlesPlatform limits, the SMS 160 vs 70 rule, and how emoji are counted. Tool: Character Counter · Published Sep 30, 2026
💻 Developer and security guides
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Common JSON Errors and How to Fix ThemReal error messages, what they mean, and how to fix each one. Tool: JSON Formatter · Published Sep 30, 2026
</>What Is Base64? Uses, Size Overhead and Why It Isn't EncryptionHow it works, the 33% size cost, and why it's not encryption. Tool: Base64 Encoder / Decoder · Published Sep 30, 2026
🆔UUID Versions Explained: What They Are and When to Use EachVersions 1–8, the real collision odds, and v4 vs v7. Tool: UUID Generator · Published Sep 30, 2026
🔐How Strong Is Your Password? Length, Entropy and PassphrasesEntropy tables, guessing times, and why length beats complexity. Tool: Password Generator · Updated Oct 16, 2026
⇄ Everyday conversions
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How to Pick a Fair Random Winner for a GiveawayRules, a clean list, the draw, and how to prove it was fair. Tool: Random Number Generator · Published Sep 30, 2026
⇄Metric vs Imperial: Conversion Cheat Sheet for Cooking and TravelCooking, oven, travel and storage conversions in one place. Tool: Unit Converter · Published Sep 30, 2026