Japan Furusato Nozei (Hometown Tax) Donation Cap Calculator

Last updated: 2026-05-05

Japan's furusato nozei (hometown tax) explained

Furusato nozei (ふるさと納税, literally "hometown tax") is a Japanese government scheme that lets any Japanese tax resident donate to municipalities across Japan, receive a thank-you gift worth up to 30% of the donation, and recover the bulk of the donation as a reduction in next year's resident tax — with a small income-tax refund on top when a tax return is filed. It is specific to Japan's tax system and available to anyone who pays Japanese income tax and resident tax, including most foreign nationals on long-term visas.

The mechanism is straightforward in principle: all but the first ¥2,000 of total donations is refunded, so the common summary is "a gift for only ¥2,000 out-of-pocket." That holds only inside the donation cap. Donations above the cap are treated as an ordinary charitable donation, almost none of which comes back. The cap is the number this calculator computes.

This calculator is built around FY2025 (Reiwa 7) Japanese tax rules and reflects:

• Spouse and special-spouse deductions (with the 9M / 9.5M / 10M JPY taxpayer-income phase-out)
• Four dependent brackets (general, specific 19–22, co-resident elderly 70+, other elderly 70+)
• iDeCo / small-business mutual aid contributions
• Life and earthquake insurance premium deductions
• Medical expense deduction (with the 100K / 5%-of-income threshold rule)
• Single-parent and widow deductions
• Three disability brackets (general, special non-co-resident, special co-resident)
• High-income basic-deduction phase-out (24M / 24.5M / 25M JPY)
• Housing loan tax credit — both income-tax consumption and resident-tax flow-through

The cap formula

For a salaried employee in the standard case, the donation cap is:

$\text{cap} = \frac{\text{resident tax (income portion)} \times 0.20}{1 - 0.10 - \text{income tax rate} \times 1.021} + 2{,}000$

Where:

• Resident tax (income portion) = taxable income (resident-tax basis) × 10%
• Income tax rate = your marginal rate from Japan's 7-bracket progressive table (5% to 45%)
• 1.021 = the special reconstruction income tax surcharge (2.1%)

The denominator $1 - 0.10 - r \times 1.021$ is the share of the donation that comes back as combined deductions and refunds. A higher marginal rate makes the denominator smaller and the cap larger.

Quick reference (single, social insurance ≈ 15% of salary)

A spouse deduction (~¥380K) reduces the cap by roughly ¥10K at the ¥5M salary level. A specific dependent (university-age child) reduces it by more, and so on.

Eligibility

Anyone who is a Japanese tax resident and actually pays income tax and resident tax. That includes most foreign residents on long-term visas (engineer/specialist, business manager, spouse, permanent resident, etc.). The mechanism is identical regardless of nationality — the donation is deducted from the following year's resident tax, with a refund on income tax if a return is filed.

Practical considerations for foreign residents:

• One-Stop Exception forms are in Japanese. The municipality mails a form (in Japanese) after the donation, and it must be submitted by January 10. Where Japanese is limited, filing a tax return (確定申告) with all donation receipts may be easier — the e-Tax system has limited English UI but municipality donation receipts can be filled in numerically.
• Donation portals partially support English. Furunavi, Satofull, Furusato Choice, Rakuten Furusato Nozei, etc., have varying levels of English UI; reward gift descriptions are mostly Japanese.
• Reward gifts are sent to the registered address. The address on each donation should match the donor's jūminhyō address.
• Non-residents (those not subject to Japanese tax on worldwide income) generally cannot use furusato nozei effectively. A person with only foreign-source income should consult a tax accountant.

Timeline

In furusato nozei the "salary year", "donation year", and "deduction year" are three distinct moments. For a 2025 (Reiwa 7) donation:

The figure to enter as "annual salary" is the salary expected for the donation year, not the figure on a withholding tax statement from a previous year. A practical pattern is to wait until late November or early December, when bonuses are mostly known, then run the calculator and donate.

Verifying the calculation step-by-step

The "Show calculation steps (optional)" panel reveals every intermediate value: employment income deduction → employment income → basic deduction → spouse deduction → dependent deduction → medical/insurance/iDeCo deductions → taxable income (income tax basis vs resident tax basis) → marginal income tax rate → resident tax (income portion). When the housing loan credit is non-zero, additional rows show how it splits between income tax and resident tax.

This is the panel to open when a real withholding tax statement (源泉徴収票) is in hand and the goal is to confirm that this tool produces numbers consistent with the official figures.

Planning guidance

Year-end timing

Furusato nozei must be donated within the calendar year for which the deduction is intended (taking effect the following year). Mid-November to early December is the usual window — annual income is mostly known by then and popular reward gifts are still in stock. December gets crowded and many gifts run out of stock.

One-Stop Exception versus filing a tax return

For a donor giving to 5 or fewer municipalities who does not otherwise need to file a tax return, the One-Stop Exception is the lighter path: each municipality emails or mails a form, returned (in Japanese) by January 10. Giving to 6+ municipalities, claiming medical expenses, claiming first-year housing loan credit, or having side income requires a tax return; in that case all donation receipts are submitted together with the return. Where both One-Stop forms and a later tax return are filed, the One-Stop submissions are nullified — the tax return takes precedence.

Safety margin

The "recommended cap (5% safety margin)" output guards against mid-year changes — a smaller bonus, a new dependent, an unplanned medical expense. Donating up to the recommended cap typically absorbs these without overshooting. After late December, when essentially everything is fixed, donating up to the theoretical cap is reasonable.

How the housing loan tax credit interacts with the cap

The housing loan tax credit (住宅借入金等特別控除) is unique among the supported deductions because it is a tax credit, not an income deduction. It applies in two stages:

1. Income tax first: the credit is subtracted from pre-credit income tax. If it fully consumes the income tax, the would-be income-tax refund part of furusato nozei effectively disappears — this tool conservatively sets the effective income tax rate to 0 in the cap formula.
2. Resident tax flow-through: any leftover credit (after consuming income tax) flows into resident tax, capped at ¥136,500 per year for residences acquired from April 2022 onward. This directly reduces the income-proportional portion of resident tax, which is the base figure for the 20% special-portion cap of furusato nozei.

Worked example: salary ¥7,000,000, single, housing loan credit ¥350,000 per year:

• Income tax before credit ≈ ¥296,500
• Credit consumed by income tax = ¥296,500 (exhausted)
• Leftover ¥53,500 flows into resident tax (within the ¥136,500 cap)
• Resident tax (income portion) was ¥377,000; effective resident tax becomes ¥323,500
• Cap drops to roughly ¥73,889 (vs. ~¥109,000 without housing loan credit)

In the first year or two of home ownership, when the credit is largest, the housing loan credit amount should be entered. It appears on the withholding tax statement under "housing loan tax credit amount" (住宅借入金等特別控除の額), or can be estimated as year-end loan balance × 0.7%.

What this tool does not cover

• Income-amount-adjustment deduction (max ¥150,000) for salaries above ¥8.5M with dependents under 23. If this applies, your taxable income is slightly lower than this tool computes, so the tool may slightly overstate the cap.
• Differential resident-tax caps for life and earthquake insurance. The income-tax cap (¥120K / ¥50K) is used on both sides; resident-tax actual caps are ¥70K / ¥25K. The cap may be overstated by up to about ¥5,000.
• Pre-2014 housing loan resident-tax cap of ¥97,500 (the tool uses ¥136,500 across the board). For older contracts the cap may be overstated by up to about ¥4,000.
• Retirement allowances, capital gains, real estate income, etc. Salary-only assumption.
• Municipal surtaxes that some cities apply on top of the standard 10% resident tax.

Furusato nozei is a clear and reliable benefit inside the cap, but everything above the cap reverts to ordinary charity. The tool gives an estimate; re-running it with finalized numbers from the withholding tax statement is advisable before making large donations. A person with multi-source income or a salary above ¥15M should also consult a Japanese tax accountant.

Once the donation cap is locked in, the savings calculator can project what to do with the rest of the year-end cash — setting the monthly contribution to whatever would otherwise have been over-donated shows the year-by-year compounding on the chart.