About CalcSpin

What it is

CalcSpin is a set of free tools for quick everyday calculations and decisions. These are the English tools available now:

Fun & Decision Tools

Small tools for small decisions. Everything runs in your browser.

Everyday Tools

Quick calculators and converters for everyday errands.

The site also has Korean tools, including Korean tax and money calculators: 세금·돈 계산 (7), 놀이·결정 도구 (5), 생활 도구 (2).

Principles

Everything you type is calculated in your browser and is never stored.
Rules and rates come from official sources, and each page shows the date they were checked.
Cases a tool cannot handle are listed openly rather than hidden.
The site gives no tax, legal or financial advice and does not overstate its results.
Each tool’s calculations have automated tests that run before every release.

Who runs it

디에이치소프트 (CEO 하정도, business registration no. 587-32-01583), Republic of Korea. The same business runs the document tool Sseuda. For error reports and questions, email sseuda.help@gmail.com (English is fine).