HandyTools
Calculator and Everyday Math: Practical Guide
Learn arithmetic, percentages, date differences, age calculations, and unit conversions with examples.
Read the guide →Start here
New to HandyTools? These quick steps help you get a useful result.
1. Choose a guide
Pick the task you want to complete and review the steps and examples.
2. Open a free tool
Use the related calculator or image utility directly in your browser.
3. Check your result
Preview output, confirm units or dimensions, and download or copy when ready.
Image guides
Learn to optimize image size, dimensions, and quality for websites and social platforms.
Browse all guides
How to Calculate Percentage Change
Learn the percentage-change formula with worked examples for increases, decreases, and common mistakes.
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How to Compress Images for Websites
Learn how image dimensions, file formats, and compression settings affect file size and visual quality.
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How to Resize Images for Social Media
Learn about aspect ratios, image dimensions, cropping, and exporting artwork for social media placements.
Read the guide →Calculator and everyday math guides
Understand formulas with worked examples, then verify your answer using a HandyTools calculator.
Percentages and change
Learn percentage increases, decreases, and comparisons using simple formulas.
Dates and age
Use date and age calculators carefully, checking start dates and leap-year details.
Units and measurements
Choose the correct input and output units before comparing measurements.
How to use HandyTools
Works in your browser
Open a tool page and follow its on-screen controls. For image tools, use files you have permission to use.
Protect your original files
Keep a copy of important images or text before editing. Check the result before replacing an original.
Need more help?
Visit our About page for site information or Contact page to report a problem.
Social media image help
Prepare images with suitable dimensions and proportions to reduce unwanted cropping.
Resize images for social media
Learn about aspect ratios and dimensions for posts, stories, covers, and thumbnails.
Read the full social media image guide →