About toin

toin is a small collection of calculators and everyday tools. Each one does a single thing, loads instantly, and asks nothing of you — no account, no upload, no permission prompt.

How the tools are built

Every calculation runs in your browser. That is a deliberate choice rather than a technical shortcut: it means the tool keeps working on a bad connection, your input never travels anywhere, and there is no server that could log what you typed.

The pages ship almost no JavaScript. A date calculator does not need a framework, so it does not load one. That is why these pages open faster than most of the alternatives.

Accuracy

Date arithmetic is easier to get wrong than it looks. Most online age calculators convert dates to a millisecond timestamp and divide, which drifts by a day around leap years and across time zones. toin compares calendar components directly, and the logic is covered by an automated test suite that includes leap centuries, 29 February birthdays and daylight-saving transitions.

Who makes it

toin is built and maintained by Marcio Toledo at Toledo Interactive.

Suggestions

The tools that get built next are chosen partly from what people ask for. If something is missing or wrong, write to admin@toin.app — it reaches us directly.