Understand it. Then do it.
Short, practical guides for the everyday questions behind UsefulFox tools.
How to Make a QR Code for a Website
Create a QR code for any web page, choose a practical image size and test it properly before printing or sharing.
Best QR Code Size for Printing
Choose a reliable size for labels, menus, leaflets, posters and signs, then test the final printed proof.
Static vs Dynamic QR Codes
Compare editing, tracking, privacy, cost and long-term reliability before choosing a QR code type.
How to Test a QR Code Before Printing
Check the destination, artwork, phone compatibility, lighting and final physical proof before publication.
How to Merge PDF Files
Combine several PDFs into one document, preserve the right order and check the finished file before sharing.
How to Split a PDF and Extract Pages
Extract selected pages, understand page ranges and avoid the most common PDF numbering mistakes.
How to Compress a PDF Without Making It Unreadable
Reduce PDF file size for email and uploads while keeping text, signatures and images clear.
How to Convert JPG Images to One PDF
Prepare, order and combine photographs or scans into a practical multi-page PDF.
How to Convert PDF Pages to JPG Images
Create page images for presentations, websites and sharing while protecting quality and privacy.
How to Reduce Image File Size Without Losing Quality
Reduce image file size without making pictures look noticeably worse. Learn when to resize, compress or change format, then use UsefulFox to do it in your browser.
How to Make an Image Smaller for Email
Make a photo or image small enough to email without destroying its appearance. A practical guide to resizing, compression and choosing a suitable format.
JPG vs PNG vs WebP: Which Image Format Should You Use?
Compare JPG, PNG and WebP for photos, transparency, screenshots, websites and file size. Choose the right format, then convert or compress it with UsefulFox.
How to Calculate a Percentage Discount
Work out a percentage discount, the amount saved and the final sale price with a simple formula and worked examples.
How to Calculate Percentage Increase and Decrease
Learn the percentage change formula with clear examples for price rises, reductions, growth and comparisons.
How to Calculate Percentages
A simple guide to percentages, percentage increase, discounts and everyday percentage calculations.
How to Calculate VAT in the UK
Understand net, gross and VAT amounts, including how to add or remove a 20% VAT rate.
How Many Days Are Between Two Dates?
Learn the difference between elapsed and inclusive day counts and calculate date gaps quickly.
How to Compress an Image Without Ruining It
Reduce image file size while keeping enough visual quality for websites, email and everyday sharing.
How Much Paint Do I Need?
Estimate paint quantity from wall area, coats and manufacturer coverage without overbuying.
How Long Should a Password Be?
Understand how length, randomness and character choice affect password security.
Passphrase vs Password
Compare random passwords and random-word passphrases for security and memorability.
What Makes a Password Strong?
Learn how length, randomness, uniqueness and entropy work together.
How Random Password Generators Work
Understand cryptographic randomness, unbiased selection and private browser generation.
Password Security: A Practical Guide
Create stronger passwords, avoid reuse and understand why length and uniqueness matter.