How to File a Kakuteishinkoku for FX Income in Japan: 2026 Guide

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If you trade foreign exchange (FX) in Japan, you have likely encountered the word kakuteishinkoku (確定申告) — Japan’s annual income tax return. Filing it correctly for FX income is not as straightforward as it sounds. FX profits are taxed under a special category, reported on a separate schedule, and subject to a flat rate that differs from ordinary income tax. Miss a step or use the wrong form, and you risk penalties, overpaying, or losing the right to carry forward losses.

This guide walks you through everything you need to know about filing a kakuteishinkoku for FX income in Japan in 2026: whether you need to file, what documents to gather, how FX profits are classified under Japanese tax law, and how to complete the process via e-Tax from start to finish.

Do You Need to File a Kakuteishinkoku for FX Income?

Whether you are legally required to file depends primarily on your employment status and the size of your FX profits. Here is how the rules break down:

Salaried Employees (Salary Income)

If you are a company employee whose taxes are handled through year-end adjustment (年末調整), you are still required to file a kakuteishinkoku if your FX profit for the year exceeds ¥200,000. This threshold applies to the combined total of all miscellaneous income and side income outside your main salary.

If your FX profit is ¥200,000 or below, you are technically exempt from filing an income tax return with the National Tax Agency (NTA). However — and this is an important caveat — you are not exempt from paying residence tax (住民税). Your municipality collects residence tax based on total income, including FX income. This means even if your FX gains fall under the ¥200,000 threshold, you may still need to file a separate residence tax declaration with your local ward or city office, depending on local rules. Check with your municipality directly.

Self-Employed / Freelancers / Business Owners

If you are self-employed or run your own business, you are required to file a kakuteishinkoku every year regardless of the amount of your FX income. FX profits (or losses) must be reported in addition to your regular business income.

Anyone with FX Losses

Even if your FX trading resulted in a net loss for the year, filing a kakuteishinkoku is strongly advisable. Japan’s tax law allows you to carry forward FX losses for up to three years, offsetting future gains. You forfeit this benefit entirely if you fail to file.

Non-Residents and Visa Status

Tax residency in Japan is determined by domicile, not citizenship or visa type. If you lived in Japan for more than 183 days in the tax year, you are generally treated as a resident taxpayer and are subject to Japanese tax on worldwide income, including FX income from overseas brokers.

Key Dates for the 2026 Filing Season

The kakuteishinkoku filing season for income earned in the 2025 calendar year (Reiwa 7) runs as follows:

Late filing (期限後申告) is possible but triggers a late-filing penalty (無申告加算税) of 5–15% of the tax owed, plus delinquency interest (延滞税) that accrues daily. It is always better to file late than not at all — the penalty is lower than the cost of non-filing discovered during an audit.

If you are due a refund (還付申告), you can file as early as January 1, and there is no strict deadline — refund filings are accepted year-round. However, refund claims expire after five years, so do not leave money on the table.

Documents You Need Before You Start

Gather the following before you begin. Missing any of these will stall your filing.

Checklist

• Annual trading statement (年間取引報告書) — Issued by your FX broker, typically in January for the previous year. This is the core document. It shows total profit/loss, number of contracts, and any withholding tax. Download it from your broker’s member portal.
• Withholding tax certificate (支払調書 or 特定口座年間取引報告書) — If your broker withheld tax on your behalf (unusual for FX, but relevant for some account types), you will need this slip.
• My Number card (マイナンバーカード) — Required for e-Tax login and identity verification. If you do not have the card itself, you can use your My Number notification slip plus a photo ID, but the card is strongly recommended for a smooth e-Tax experience.
• Schedule 3 (第三表: 分離課税用) — The separate taxation schedule appended to Form B. This is where FX income is entered. It is not a physical document you gather — you select it during the filing process — but knowing it exists will save you confusion.
• Attachment for futures transactions (先物取引に係る雑所得等の計算明細書) — A supporting worksheet that details your FX profit/loss calculation. Available on the NTA website or auto-generated in e-Tax.
• Bank account information — For receiving refunds or making payments via direct debit.
• Previous year’s return (if applicable) — Needed if you are carrying forward losses from prior years.

How FX Income Is Classified Under Japanese Tax Law

This is where many filers go wrong. FX income in Japan is not classified as ordinary miscellaneous income (雑所得) in the standard sense. It falls under a specific sub-category:

先物取引に係る雑所得等 (Miscellaneous income from futures transactions)

This classification is established under Article 41-14 of the Special Taxation Measures Law (租税特別措置法). Domestic FX trading (行為差金決済取引) conducted through licensed Japanese brokers is explicitly included.

Tax Rate: Separate Taxation at 20.315%

Because FX income is classified as futures-related miscellaneous income, it is subject to 申告分離課税 (separate self-assessed taxation), not the progressive income tax brackets that apply to salary income. The flat rate is:

This rate applies regardless of how much you earn. Whether your FX profit is ¥300,000 or ¥30,000,000, the tax rate is the same 20.315%. This is both good news (high earners avoid top bracket rates of up to 55%) and important to understand (you cannot offset FX income against salary income to reduce your bracket).

Loss Carryforward

Net losses on FX can be carried forward for up to three years and offset against future FX profits, reducing your tax in profitable years. This is only available if you file every year, including loss years.

Step-by-Step Filing via e-Tax

The easiest and most reliable way to file is through e-Tax, the NTA’s online filing system at https://www.e-tax.nta.go.jp/ . Here is how to complete the process from scratch.

Step 1: Get Your Annual Trading Statement from Your Broker

Log in to your FX broker’s member portal and download the 年間取引報告書 for the previous calendar year. Most major brokers (GMO Click, DMM FX, SBI FX Trade, Saxo Bank Japan, etc.) make this available by mid-January.

Key figures you will need from this document:

• Total realized profit/loss (決済損益)
• Swap interest received/paid (スワップポイント) — this is also taxable and must be included
• Any fees charged by the broker that offset your profit

Note: Unrealized (open) positions at year-end are not included in that year’s taxable income. Only closed trades count.

Step 2: Log In to e-Tax with Your My Number Card

Navigate to https://www.e-tax.nta.go.jp/ and select 確定申告書等作成コーナー (Tax Return Preparation Corner). You will be prompted to authenticate:

• With My Number card: Use a card reader or the smartphone NFC authentication app (マイナポータルアプリ). This is the most seamless option.
• With ID/password: If you obtained an e-Tax ID and password from your local tax office, you can use those instead.

For first-time filers, allow extra time to set up your authentication method before the filing deadline.

Step 3: Select Kakuteishinkoku-sho B and Schedule 3

In the filing preparation interface, select:

1. 確定申告書B (Form B) — This is the general-purpose form used for all income types other than employment-only filers.
2. 第三表 (Schedule 3: 分離課税用) — The separate taxation schedule. Selecting this will add the FX income section to your return.

If you are a salaried employee also reporting salary income, you will enter your salary details on Form B as well. The two streams (salary income and FX separate income) coexist on the same return.

Step 4: Enter FX Income in the Futures Transactions Section

In Schedule 3, locate the section labeled 先物取引に係る雑所得等. You will enter:

• Total income amount (収入金額): Gross receipts from FX trading (total profit before expenses)
• Necessary expenses (必要経費): Deductible costs directly related to FX trading (see the expenses section below)
• Net income (所得金額): Income minus expenses
• Carried-forward loss from prior years (前年分からの繰越損失額): If applicable

The system will automatically calculate the 20.315% tax on your net FX income.

Also fill in the 先物取引に係る雑所得等の計算明細書 (calculation detail worksheet). This is an attachment to your return that provides a breakdown of trades. For most retail traders, the annual trading statement from your broker maps directly onto this form.

Step 5: Review and Submit

Before submitting:

• Double-check that your FX income figures match your broker’s annual statement exactly
• Confirm your bank account details for refunds or direct debit payment
• Review the final tax calculation

Once satisfied, click submit (送信). e-Tax will generate a confirmation number. Save this — it is your proof of filing.

If you owe tax, you can pay via:

• Direct debit (口座振替) — set up in advance
• Pay-easy (ペイジー) — via internet banking
• Credit card (クレジットカード納付) — a convenience fee applies
• Convenience store payment — using a QR code or payment slip

Using Accounting Software to Simplify the Process

If you have multiple income streams — freelance income, rental income, or investment income alongside FX — manually preparing Schedule 3 and the supporting worksheets can become time-consuming. freee can generate your filing documents and submit directly to e-Tax, consolidating all your income sources into a single, submission-ready return. It supports Schedule 3 and the futures transactions attachment, which makes it particularly useful for FX traders who also have business or freelance income.

Common Mistakes When Filing FX Income

Mistake 1: Filing FX Income as Ordinary Miscellaneous Income

This is the most consequential error. Some filers — or even some accountants unfamiliar with FX — enter FX profits in the standard miscellaneous income (雑所得) section of Form B instead of in Schedule 3 under separate taxation. This is incorrect. Regular miscellaneous income is subject to progressive tax rates (up to 45% nationally, plus residence tax), meaning you could pay far more than the correct 20.315% flat rate. The NTA may also flag the inconsistency.

Always use 第三表 (Schedule 3) and the 先物取引に係る雑所得等 classification.

Mistake 2: Forgetting to Claim Deductible Expenses

Many traders are unaware that legitimate expenses directly related to FX trading can be deducted from gross profit, reducing taxable income. These are not large amounts for most retail traders, but they are real deductions you are entitled to. See the expenses section below.

Mistake 3: Not Filing Loss Years

If your FX trading resulted in a net loss, you might think there is nothing to file. However, not filing means you cannot carry that loss forward to offset future profits. Over a three-year period, a loss year left unfiled could cost you tens of thousands of yen in unnecessary tax on subsequent profitable years.

Mistake 4: Ignoring Swap Income

Swap points (スワップポイント) — the interest-like income earned from holding certain FX positions overnight — are taxable FX income and must be included in your total. Your broker’s annual trading statement should include this figure, but double-check that you are reading the statement correctly.

Mistake 5: Using the Wrong Year’s Figures

The kakuteishinkoku filed in early 2026 covers income earned between January 1 and December 31, 2025. Confusion sometimes arises because you are filing in 2026 for 2025 income. Make sure your broker statement covers the correct calendar year.

Mistake 6: Missing the Deadline Without Filing for Extension

Unlike some other countries, Japan does not have a general filing extension system for individuals. If you cannot file by March 15, you should still file as soon as possible. A late-filed return (期限後申告) incurs penalties, but those penalties are lower than what results from an NTA-initiated assessment (更正処分) discovered during a later audit.

Deductible Expenses for FX Trading

Japanese tax law allows you to deduct necessary expenses (必要経費) that are directly and clearly related to your FX trading activity. The standard for deductibility is that the expense must be incurred in order to generate the FX income — it cannot be a personal expense that merely overlaps with trading.

Commonly accepted deductible expenses include:

What is not deductible:

• Losses from other investment types (stock losses cannot offset FX income)
• General living expenses, even if you “think about FX” while using them
• Travel to overseas markets or exchanges (rarely accepted without very specific business purpose)

The NTA requires documentation. Keep receipts, invoices, and bank statements for all claimed expenses. In practice, the amounts involved for a retail FX trader are usually modest, but the deductions are legitimate and worth claiming.

Conclusion

Filing a kakuteishinkoku for FX income in Japan requires attention to classification, form selection, and timing. The critical points to remember are: FX income falls under 先物取引に係る雑所得等 on Schedule 3, is taxed at a flat 20.315%, and must be reported whether you made money or lost it — because losses are only valuable if you file them. The e-Tax system makes the process manageable once you have your broker’s annual trading statement in hand.

Start collecting your documents in January, authenticate your My Number card for e-Tax early, and give yourself time before the March 15 deadline to work through the Schedule 3 worksheet. If you have multiple income streams, accounting tools can save significant time.

Ready to estimate your tax before you file? Calculate your FX tax with our FX Profit Calculator .

Have other income sources alongside FX? Understand your full tax picture with our Side Income Tax Calculator .

Related Tools

Calculate forex profits → Forex Profit Calculator Estimate your tax bracket → Tax Bracket Calculator

This article is for general informational purposes. Tax rules change annually — always confirm the current rules with the NTA website (nta.go.jp ) or a qualified tax professional (税理士) before filing.

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