About ToolBox Inside

ToolBox Inside is a free collection of online tools including calculators, image processing tools, and text utilities. All tools run locally in your browser — your data never leaves your device.

Our Philosophy

Privacy First

All processing happens locally in your browser. No data is uploaded to any server.

Fast & Easy

No registration required. Apple-inspired design for a smooth user experience.

Bilingual

All tools and blog content available in both Chinese and English.

Completely Free

All tools are free to use. Supported by non-intrusive advertising.

How we ensure accuracy

The biggest risk in a calculator is getting the math wrong. We validate every formula against authoritative sources (for example BMI = weight ÷ height², and compound interest A = P(1 + r/n)^nt), and regression-test against known examples. For items that change with policy — taxes, housing fund — we label the applicable scope and last-updated date, and revise when rules change. If you spot a questionable result, tell us via the contact page and we'll investigate immediately. The logic and assumptions behind each tool are detailed on our Methodology & Accuracy page.

Tool Categories

Calculators (16) — Mortgage, Tax, BMI, Date, Housing Fund, Compound Interest & more
Image Tools (5) — Compression, Format Conversion, Resize, Base64, Color Picker
Text Tools (11) — Word Counter, JSON Formatter, Base64 Encode/Decode, UUID Generator & more

Tech Stack

Built with pure static HTML/CSS/JavaScript with no backend dependencies at runtime (charts use a local copy of Chart.js). The site is deployed on Vercel's global Edge Network for fast access worldwide. Every tool's logic is transparent — see our Methodology & Accuracy page.

Contact

Have feedback or suggestions? Get in touch.