How to Process Foreign-Currency Credit Card Expenses Correctly

Foreign-currency credit card transactions can trip up even experienced finance teams. The moment you swipe your card abroad, two exchange rates enter the picture: the rate on the transaction date and the rate that appears on your monthly statement. Getting these right is not just good bookkeeping — in Japan it is a legal requirement under Corporate Tax Basic Directive 13-2-1-2. This guide walks you through the rules, the maths, and the practical steps to keep your expense reports clean.

Why the Transaction Date Rate Matters

Under Corporate Tax Basic Directive 13-2-1-2 (Japan's foundational rule for foreign-currency accounting), a foreign-currency expense must generally be translated into yen using the exchange rate prevailing on the transaction date — not the billing date, not the payment date.

This matters because exchange rates move. During the window from 28 April 2026 to 28 May 2026, the JPY/USD rate ranged from a low of 0.0063 to a high of 0.0064 — a swing that, while modest (+0.16% over 21 days), can add up across dozens of transactions in a busy travel month. The JPY/EUR rate moved even more, from a low of 0.0053 to a high of 0.0055, representing a +0.56% change over the same 21-day period. On a large invoice, that difference is real money.

Practically speaking, "the rate on the transaction date" means the telegraphic transfer selling rate (TTS) published by your bank for that day, unless your company's accounting policy specifies a different approved rate such as a monthly average.

A Concrete Calculation Example

Suppose a business traveller charges a USD 500 hotel bill on 28 April 2026. The JPY/USD rate that day is 0.0063 (meaning 1 JPY = 0.0063 USD, or equivalently 1 USD ≈ 158.73 JPY).

Item

Value

Foreign-currency amount	USD 500.00
JPY/USD rate on transaction date	0.0063
USD → JPY conversion (500 ÷ 0.0063)	¥79,365

Now imagine the credit card statement arrives in late May and the card company applied a rate of 0.0064 (the period high). The card charges ¥78,125 (500 ÷ 0.0064). The ¥1,240 difference between your booked expense (¥79,365) and the actual card charge (¥78,125) must be recorded as a foreign-exchange gain — it cannot simply be ignored or netted off.

If the traveller had instead spent EUR 500 on the same date at 0.0053 (the period low for JPY/EUR), the yen equivalent would be ¥94,340. Had the rate been the period high of 0.0055, the equivalent drops to ¥90,909 — a gap of more than ¥3,400 on a single transaction.

Booking the Exchange Difference

Most accounting systems handle this through a foreign-exchange gain or loss account (為替差益 / 為替差損 in Japanese). The workflow looks like this:

1. At transaction date — debit the expense account at the transaction-date rate (e.g., ¥79,365 for the USD 500 example above).
2. At payment / statement date — debit or credit the foreign-exchange difference account for the gap between the booked rate and the card-settlement rate.
3. At period end — any outstanding foreign-currency payables must be revalued at the closing rate under the same directive.

Keeping this three-step discipline ensures your profit-and-loss statement reflects true economic cost and your tax return is defensible under Corporate Tax Basic Directive 13-2-1-2.

Documentation and Internal Controls

Good documentation is your first line of defence in a tax audit. For every foreign-currency card transaction, retain:

• The original receipt showing the foreign-currency amount and date
• A screen capture or printout of the bank's published TTS rate for that date
• The credit card statement line showing the yen settlement amount
• A brief reconciliation note explaining any exchange difference

If your company processes high volumes of overseas expenses, consider adopting a monthly average rate for convenience — Corporate Tax Basic Directive 13-2-1-2 permits this under certain conditions — but apply it consistently across the entire accounting period. Switching methods mid-year without proper justification raises red flags.

Internally, require employees to submit expense reports within a fixed window (many companies use 10 business days) so that the transaction-date rate is still easily traceable and the foreign-currency difference stays small.

Closing Your Expense Reports Efficiently

Manually hunting down exchange rates for every overseas charge is time-consuming. Zenrate (zenrate.app) is a progressive web app (PWA — a web application that works like a native app on any device) that provides real-time and historical currency conversion, letting you look up the exact transaction-date rate and attach it directly to your expense report — helping your team stay compliant with directives like 13-2-1-2 without the spreadsheet headache.

Disclaimer: This article explains general accounting practice under Japanese corporate tax rules; individual circumstances vary. Consult a qualified tax professional or certified public accountant before finalising your company's foreign-currency accounting policy.

References

• Corporate Tax Basic Directive 13-2-1-2 (Japan): https://www.nta.go.jp/law/tsutatsu/kihon/hojin/13_02/01.htm