USD to JPY

Reference notes for USD/JPY

When you typically see USD/JPY

Reverse of jpy-to-usd. The dominant use case is US-domiciled individuals or businesses paying Japan-domiciled vendors: US importers paying Japanese suppliers in USD with the supplier then receiving JPY after their bank's FX, US consumers buying directly from Japanese e-commerce sites priced in USD via Shopify Japan storefronts, US conference organizers reimbursing Japanese speakers. The other steady source: US travelers to Japan converting hotel and meal receipts back to USD for expense reports filed under US accounting policies. A two-week Japan trip generates 30–50 receipts; each needs the rate from its specific transaction date in USD terms, which is U.S. Treasury or Mizuho-cross depending on company policy.

How USD/JPY behaves in accounting

For a US-domiciled company, this pair's reference rate is the U.S. Treasury reporting rate, published quarterly. Treasury's coarseness (one rate per quarter) is fine for fiscal close but inappropriate for individual travel receipts; for those, US companies typically use a daily rate from a commercial vendor and the policy column on the expense report cites that vendor. Zenrate's Treasury fetcher returns the latest available rate on or before the requested date, which can lag by up to three months. For a Japanese-domiciled company recording USD income, the canonical rate is Mizuho TTM (or MUFG/SMBC) on the receipt date. Mizuho USD/JPY is the densest, most-watched series in the entire rate-source catalog. Cross-policy mismatch is the main accounting risk: a US-filed expense report citing Treasury rates and the same trip's reimbursement booked on Japanese books at Mizuho TTM will not square. This is normal — both are right for their respective accounts — but documentation needs to be clear.

Common conversion mistakes for USD/JPY

Same as jpy-to-usd in reverse, with one addition specific to US filing: applying the wrong Treasury rate. Treasury publishes a rate at the end of each fiscal quarter and a mid-quarter amendment if a currency moves more than 10%. Pulling the wrong quarter's rate or missing the amendment produces visible variances. The Zenrate Treasury fetcher pulls by record_date, so the right date input matters. Second: confusing the spot rate at the moment of a wire transfer with the rate the receiving bank actually credited. Outgoing USD wires from US banks typically execute at the SWIFT correspondent's rate plus the receiving bank's incoming-FX fee; the JPY actually credited is lower than the spot times the USD amount. Reconciling to the credited JPY produces the right number for the Japan-side books but creates a phantom "FX loss" if the US-side books expected the spot rate. Third: rounding. Mizuho TTM is published to 2 decimal places in yen; rounding intermediate calculations to fewer decimals can introduce 0.5%+ errors on large amounts.

What Zenrate stores for USD/JPY

Live conversion uses exchangerate-api.com USD-base directly — this is the canonical pair for that source. Cached twelve hours. Historical: U.S. Treasury via `packages/core/src/rate-sources/us-treasury.ts`, hitting `api.fiscaldata.treasury.gov`. Mizuho USD/JPY via dbFetcher/edgeFunction. ECB USD/JPY via Frankfurter. All six rate policies work. The prior-month-average policy for this pair averages roughly 20 Mizuho TTM values; for the Treasury source, the policy collapses to whatever single quarterly rate covers that month's transactions, since Treasury does not publish daily.

These notes describe the rate sources actually implemented in @zenrate/core/rate-sources at the time of publication. Behavior may evolve; the source code is the ground truth.