About

Operator: Kotatsu Lab

Contact: contact form (messages go privately to the operator)

What this site is

Free calculators that help foreign residents in Japan estimate common money questions: salary take-home, the pension lump-sum refund when leaving Japan, and the cost of moving into an apartment.

How it is made

• The calculators and text were drafted with the help of AI tools. Every rate is checked against the official Japanese source listed on the method & sources page, and the calculation code is tested against official worked examples.
• Rates are reviewed when official bodies publish changes (typically every March–April, and when tax law changes mid-year).
• The site does not give individual tax, legal or visa advice. See the disclaimer.