Guides
Plain-language answers to everyday questions about file formats, file sizes and calculations, each with a free tool to try.
Brix, Specific Gravity, Baumé and Oechsle Explained
Brix, specific gravity and the other scales all measure sugar. Here's what each one means and how they compare.
October 1, 2026
How to Dilute a Solution with C1V1 = C2V2
One simple formula tells you how much stock solution and water to mix. Here's how to use it, with three worked examples.
October 1, 2026
Feddan, Dunam, Acre or Hectare? Land Units in the Arab World
Land is measured in different units across the Arab world. Here's how big each one is and how to convert between them.
October 1, 2026
How to Make a Photo Small Enough for an Online Form
Forms often reject phone photos for being too large. Two quick steps, resizing and compressing, fix it.
October 1, 2026
How to Make a Bleach Sanitizing Solution Safely
The right amount of bleach depends on what you're cleaning and on your bleach's strength. Here's how to get it right, and stay safe.
September 30, 2026
JPG, PNG or WebP? How to Choose the Right Image Format
Photos, screenshots, logos and websites each suit a different format. Here's how to pick the right one, and how to convert when you need to.
September 30, 2026
How to Make a Video Small Enough to Email or Share
Phone videos are often too big to email. Lowering the resolution does most of the work, and you can do it right in your browser.
September 30, 2026
What Is a HEIC File, and How Do You Open It?
iPhones save photos as HEIC to save space, but Windows PCs and many websites can't open them. Here's what to do.
September 30, 2026