Guides
Guides
Practical reference guides from Digital Tool Space: length conversions, image formats and QR code best practices.
Each guide is a standalone reference you can bookmark and use even if you never open one of our tools. They explain the practical decisions behind the conversions, formats and codes people ask about most.
Which guide do I need?
- Convert measurements (cm, inches, feet, miles): Length Conversion Reference
- Choose an image format or optimize an image: Image Formats Guide
- Create or print a QR code: QR Code Best Practices
Length Conversion Reference
Common real-world measurements for centimeters, millimeters, inches, feet, meters, kilometers and miles, including paper sizes, screen dimensions and credit-card sizes.
JPG vs PNG vs WebP
A practical guide to choosing between JPG, PNG and WebP for photographs, transparency, graphics and website images, plus when to compress, resize or convert.
QR Code Best Practices
Guidance on QR code size, print versus screen use, quiet zones, contrast, error correction and testing, so your codes actually scan.