Guides

Practical, step-by-step guides for the STSApps tools

Short, useful walk-throughs that show how to get a real result with an STSApps tool. Each guide links straight to the tool it covers.

Calculators

How to split a group bill fairly

A clear, repeatable method for dividing a shared bill, plus the math that keeps every share honest.Updated Image tools

How to resize images for the web

How to choose dimensions, avoid upscaling, and keep image files small enough to load fast.Updated Marketing tools

How to build campaign URLs that report cleanly

How UTM parameters work, a naming convention that prevents split reports, and where QR codes fit in.Updated Calculators

How to work out percentages without second-guessing yourself

The three everyday percentage questions, a reliable way to set each one up, and quick sense checks so the answer is one you can trust.Updated Image tools

How to read hex, RGB, and HSL color codes

The three color formats you meet on the web, what each one is good at, and how to move a color between them while keeping the exact shade.Updated Calculators

How to use the Pomodoro technique without it falling apart

Where the Pomodoro method actually helps, how to run a focused interval, and the practical fixes for interruptions and tasks that do not fit a neat block.Updated Marketing tools

How to make QR codes that actually scan

What a QR code really stores, the size and contrast rules that decide whether it scans, and how to tag the link so you can see which placement drove the visit.Updated