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Japanese capital-gains tax (20.315%) — stock-sale net calculator

Japanese capital-gains tax (20.315%) — stock-sale net calculator

Estimate the 20.315% Japanese tax on listed-stock and mutual-fund capital gains (income tax 15% + 0.315% reconstruction surtax + 5% resident tax). Enter sale proceeds, acquisition cost (incl. buy-side fees) and sell-side expenses; the tool returns the gain, each tax line and the after-tax take-home. Losses display zero tax and a note about the 3-year carry-over deduction. Excludes NISA / iDeCo tax-free balances. Runs entirely in your browser — your figures never leave the device.

financetaxcalculator

How to use

Enter sale proceeds (gross amount received), acquisition cost (purchase price plus any buy-side fees) and sale expenses (sell-side broker fees). Hit Estimate tax to see the capital gain, the income tax (15%), the special reconstruction surtax (2.1% of the income tax), the resident tax (5%), the total tax, the after-tax gain and the net cash left from the proceeds. If the trade was at a loss, the tool shows zero tax and a note about Japan's three-year loss carry-over. NISA / iDeCo balances are tax-free and out of scope. Use this for 特定口座源泉徴収なし or 一般口座 sales that you plan to declare on the tax return.

FAQ

Why is the rate the odd 20.315%?
It is 15% income tax + 0.315% reconstruction surtax (2.1% of the 15%) + 5% resident tax. The reconstruction surtax funds disaster reconstruction and runs from 2013 through 2037.
What is the loss carry-over?
If you declare a capital loss on the tax return, you can offset it against capital gains over the next three years. Example: a JPY 500k loss this year and a JPY 300k gain next year → next year's taxable gain becomes zero and the remaining JPY 200k carries over. You must file a tax return every year to keep the carry alive.
What about NISA or iDeCo gains?
Both are tax-free, so they are out of scope. Selling inside a NISA account never triggers this tax.
Do I need it for 特定口座源泉徴収あり accounts?
Not usually — the broker withholds 20.315% automatically and no return is required. But you can still file to net losses across brokers, in which case this tool is handy for a quick estimate.
Can I use it for cryptocurrency gains?
No. Crypto gains are 雑所得 (miscellaneous income) under the progressive system (up to ~55%), not the 20.315% flat rate. This tool only fits listed-stock and mutual-fund gains.
Is my input uploaded?
No. The calculation runs entirely in your browser — your proceeds and cost numbers never leave the device.

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