The 0.3% on a term deposit is a headline number. If prices are rising 2% a year, what you can buy shrinks while the money sits there.
The real interest rate is what explains that gap, and the arithmetic is one subtraction. It changes how you read savings, borrowing and the news.
This is written for people weighing where to keep cash, or choosing between a fixed and a variable mortgage. As of September 2026.
Nominal and real: the difference is whether you subtract inflation
The rate printed on your passbook or loan agreement is the nominal interest rate. Put 1,000,000 yen into a deposit paying 1% for a year and the balance becomes 1,010,000 yen. The number does grow.
But if prices rose 3% over the same year, what cost 1,000,000 yen now costs 1,030,000 yen. The balance gained 10,000 yen while your purchasing power fell by 20,000 yen.
The real interest rate describes what actually happened: about minus 2% in this example.
The relationship is a single subtraction, known as the Fisher approximation: real rate ≒ nominal rate − expected inflation. The exact form is more involved, but for everyday decisions this is enough.
The same “1%” can be a gain or a loss
At 0% inflation, a nominal 1% deposit means a real 1% and your purchasing power grows. At 1% inflation you break even. At 3% inflation the real rate is minus 2%: the money is shrinking while it is deposited.
As of September 2026, ordinary deposit rates in Japan mostly sit between 0.001% and 0.2%, while the consumer price index is running around 2% year on year. In other words, the real rate is negative.
“Money in the bank is safe” is a statement about the headline number. In terms of what it buys, it shrinks a little every year.
Four places where thinking in real terms changes the decision
- Savings. Whether you are really accumulating depends on the gap against inflation, not on the advertised rate. Keeping everything in an ordinary account is a position that costs something each year.
- Borrowing. A repayment fixed in nominal terms gets lighter in real terms as inflation runs, because the amount owed is frozen while incomes grow in nominal terms. In deflation the same mechanism works against you.
- Comparing where to hold cash. Yen deposits, foreign currency, dollar-linked crypto assets – line them all up in real terms and comparison gets easier.
- A yen deposit is “0.2% minus 2% inflation”, so negative in real terms. A dollar stablecoin pays no interest; its yen value rises if the yen weakens and falls if the yen strengthens.
- Reading the news. Central banks watch the real rate. “We raised the nominal rate, but inflation is higher, so policy is still accommodative” becomes a sentence you can read directly.
How judging on the headline number goes wrong
Choosing a currency for its high rate alone. A high nominal rate does not help if that country’s inflation and the fall of its currency are larger; converted back to yen, the value shrinks.
High nominal rates usually come with high domestic inflation. That basic pairing is what gets missed.
Believing that saving alone is enough. Decades of holding everything in an ordinary deposit, then noticing that what cost 10 million yen in your twenties costs 12 million now.
The balance grew; what it buys did not. That is a negative real rate compounding quietly over a long time.
In practice: separate money to protect from money to grow
While the real rate is negative, one approach is to hold only the money earmarked for overseas payments in USDC, a stablecoin that tracks the US dollar.
USDC pays no interest. It simply lets you hold dollars. Even so, in a weak-yen period it removes the yen to dollar to yen round trip, and lets you fix a payment budget in dollars.
✅ What tends to work
With the money for overseas payments already held in USDC, the budget does not need rebuilding while the yen weakens.
The point is not reaching for yield; it is avoiding the round trip through the exchange rate.
⚠️ Common pitfalls
A common trap: because the real rate is negative, moving even emergency savings into a volatile crypto asset.
Watching the price tends to take over the decision-making, which is why money to protect and money to grow have to be kept apart.
Stablecoins have their own conditions attached: the issuer, the network you use, and wallet management. Start with a small amount, get used to sending and storing, and raise the sum after that.
It is worth being precise about what this solves. Holding dollars does not earn a return, and it does not protect you if the dollar itself weakens.
What it removes is a specific cost: converting yen into dollars to pay a bill, after converting dollars into yen a few weeks earlier out of habit.
Once the currency held matches the currency about to be spent, the budget for that portion stops depending on the exchange rate.
Japan’s rate environment as of September 2026
The Bank of Japan has been normalising policy in stages, while consumer prices run around 2%. The ten-year government bond yield has been moving in the mid-1% range.
Nominal rates are drifting up; real rates remain low and at times negative.
In that environment, where cash sits matters. Before concluding that deposits are fine again because rates have risen, subtract the inflation rate. If the answer is negative, leaving money there carries a cost.
A note on borrowing while prices rise
Inflation is not uniformly bad news for a borrower. The amount owed on a fixed-rate loan is frozen in nominal terms when the contract is signed.
If wages and revenue then rise with prices, the share of a month’s income needed for the same payment falls. That asymmetry is why borrowers tend to be favoured in an inflationary stretch.
The mirror image is just as real. In deflation, the frozen repayment gets heavier every year while income shrinks around it.
So “fixed or variable, now or later” is really a question about where you think real rates go. It deserves the same subtraction as everything else on this page.
In closing: the check is four lines long
- What share of your assets is cash and deposits?
- Is that deposit rate above or below recent inflation?
- Is your loan fixed or variable, and does that make sense at today’s real rate?
- Are you comparing places to hold money in real terms rather than nominal?
A quick worked example: a deposit at 0.2% with inflation at 2% gives a real rate of about minus 1.8%. On 3,000,000 yen, that is roughly 54,000 yen of purchasing power a year.
Doing this check once a year, when new consumer price figures come out, is enough for most households.
Rates and prices keep moving. Check the latest consumer price statistics and central bank releases when you decide. The habit of looking in real terms keeps an advertised percentage from steering you.
💡 To compare yen and USDC on the same yardstick
When comparing where to hold money, Crypto Rate Viewer shows what an amount of yen is worth in USDC and other crypto assets, with yen-denominated price history. No account is needed.
The figures are reference prices. An actual exchange uses the trading venue’s price and fees.
(This article is based on information as of 15 September 2026. Crypto assets move sharply in price and you may lose the money you put in. Nothing here recommends buying or selling any particular financial product or crypto asset)
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