Guides
Plain-English explainers on image formats, money math and everyday web tasks — written to go alongside the free tools on this site.
PNG vs JPG vs WebP vs AVIF
Which image format to use, when, and why — with a plain-English comparison of size, quality and support.
HEIC vs JPG: why iPhone photos won't open
What HEIC is, why Windows and older apps can't open it, and how to convert iPhone photos to JPG.
Compress images without losing quality
How image compression really works, and how to shrink files for the web while keeping them sharp.
How loan payments are calculated
The amortization formula behind every fixed-rate loan — explained, with a worked example you can follow.
Compound interest explained
How compounding makes money grow, why starting early beats saving more, and the rule of 72.
Understanding BMI and its limits
What BMI measures, what the categories mean, and the important things the number leaves out.