Real Yield vs Nominal Interest: Why Your 3% Bank Deposit Might Be Losing You Money
6 min read
Loading...
6 min read
You open your banking app and see a time deposit offer: 3% per year, guaranteed by the government. It feels safe. It sounds like free money for doing nothing.
It is not. Once you account for tax and inflation, that 3% deposit is roughly break-even in Indonesia right now, and at some banks it is a real loss. The gap between the rate a bank advertises (nominal interest) and what you actually keep after tax and rising prices (real yield) is the whole story, and almost nobody checks it before parking their money.
Nominal interest is the percentage a bank prints on the ad. It is the number everyone quotes and almost nobody adjusts.
Real yield is what that percentage is worth after two things eat into it: tax on the interest you earn, and inflation, which is the rate at which prices rise so the same rupiah buys less next year than it does today.
Real yield ≈ (Nominal rate × (1 − tax rate)) − Inflation rate
If your deposit pays 3% a year, tax takes a fifth of that, and prices are rising 2.88% a year, your money is not actually growing much at all. It might not be growing in real terms.
As of July 2026, the major state banks were offering these rupiah time deposit rates, even though Bank Indonesia's benchmark rate (the BI Rate) sat at 5.75%:
| Bank | Typical rate offered | Tenor |
|---|---|---|
| BRI | 3.50% | 3 months |
| BCA | 3.00% | 12 to 24 months |
| BNI | 2.50% | standard tenors |
| Bank Mandiri | 2.50% | standard tenors |
Source: Bisnis.com and Industry.co.id deposit rate roundups for July 2026, retrieved 4 August 2026.
Notice the gap: BI's own benchmark rate is 5.75%, but the deposit rate an ordinary saver is actually offered is roughly half that or less. Banks do not have to pass the full benchmark rate through to depositors, and in practice they rarely do.
There is also a ceiling worth knowing. The Deposit Insurance Corporation (LPS) sets a Tingkat Bunga Penjaminan, the maximum rate at which a rupiah deposit at a general bank is government-guaranteed. For June through September 2026 that ceiling is 3.50%. A deposit paying more than that is not automatically insured on the excess, so the small handful of banks advertising above 3.50% are asking you to take on uninsured risk for a fraction of a percentage point.
Source: Lembaga Penjamin Simpanan (LPS) official rate announcement, effective 1 June to 30 September 2026, retrieved 4 August 2026.
Here is the number that decides whether any of those deposit rates are worth it. Indonesia's headline inflation was 2.88% year on year in July 2026, down from 3.34% in June. Prices actually fell 0.14% month on month in July, driven by cheaper food and gold, and core inflation, which strips out volatile food and energy prices, held steady at 2.76% year on year.
Source: BPS (Statistics Indonesia) data as reported by Indonesia-Investments, retrieved 4 August 2026.
That 2.88% is comfortably inside Bank Indonesia's 1.5% to 3.5% target band. It is also higher than the after-tax return on three of the four bank deposit rates in the table above.
Deposit interest in Indonesia is not paid to you in full. Under a rule that has stood since 2000 (PP 131/2000, as amended by PP 123/2015), interest on any rupiah or foreign currency deposit with a balance above Rp 7,500,000 is subject to a 20% final income tax (PPh Final), deducted automatically by the bank before the interest ever reaches your account.
Source: Direktorat Jenderal Pajak and Ortax summaries of PP 131/2000 jo PP 123/2015, retrieved 4 August 2026.
Most people compare the advertised rate straight to inflation and stop there. That skips a step. Here is the same four banks from above, this time with tax and inflation both applied:
| Bank | Nominal rate | After 20% tax | Real yield vs 2.88% inflation |
|---|---|---|---|
| BRI | 3.50% | 2.80% | −0.08% |
| BCA | 3.00% | 2.40% | −0.47% |
| BNI | 2.50% | 2.00% | −0.86% |
| Bank Mandiri | 2.50% | 2.00% | −0.86% |
Say you put Rp 50,000,000 into a 12 month deposit at BCA's 3.00% rate.
Prices rose about 2.88% over the same period. So the Rp 51,200,000 you end the year with buys slightly less than the Rp 50,000,000 you started with bought a year earlier. On paper you made money. In terms of what that money can actually buy, you did not.
No. Deposits still do a job nothing else does well: your principal is stable day to day and, up to the LPS-guaranteed limit, protected even if the bank fails. That makes deposits the right home for an emergency fund or money you need within a few months, where the point is safety and access, not growth.
What deposits are not, right now, is a way to grow your wealth. A saver treating a 2.5% to 3.5% deposit as their main investment plan is, in real terms, standing still or slipping backward, no matter how confident the advertised percentage sounds.
Deposit rates, the BI Rate, and inflation all move independently, and the gap between them changes every time one of them does. Rather than redo this calculation by hand every few months, NetWort's Macro Context page tracks Indonesia's benchmark rate, inflation, and the rupiah exchange rate together in one place, so you can see at a glance whether cash sitting in a deposit is currently keeping pace or falling behind.