Most New Zealanders understand that inflation makes things more expensive. Fewer understand that inflation is also slowly eroding the real value of their savings — even when those savings appear to be growing.
If your savings account earns 3.5% and inflation is 3%, your real return is only 0.5%. $10,000 kept in a savings account earning below inflation loses purchasing power every year. To stay ahead, you need returns that exceed inflation — which means investing in assets like diversified index funds (historical real returns 5–7% annually after inflation) rather than holding all savings in cash. KiwiSaver growth funds have historically achieved this.
NZ Inflation History
New Zealand’s inflation is measured by the Consumer Price Index (CPI), published quarterly by Stats NZ. The Reserve Bank of New Zealand (RBNZ) targets CPI inflation at 1–3%, with a preference for the 2% midpoint.
| Year | NZ Annual CPI Inflation |
|---|---|
| 2019 | 1.9% |
| 2020 | 1.4% (COVID suppressed demand) |
| 2021 | 5.9% (supply chain disruptions, stimulus) |
| 2022 | 7.3% (peak — highest since 1990) |
| 2023 | 4.7% (declining) |
| 2024 | 2.2% (returning to target band) |
| 2025–2026 | ~2–3% (estimated, within RBNZ target) |
What drove the 2021–2022 spike:
- COVID-19 supply chain disruptions globally
- New Zealand government fiscal stimulus during lockdowns
- Post-COVID demand surge meeting constrained supply
- Global energy and food price rises
The return to target: The RBNZ raised the Official Cash Rate (OCR) aggressively from 0.25% (mid-2021) to 5.5% (2023), suppressing demand and bringing inflation back to band.
Real vs Nominal Returns
The difference between nominal and real returns is critical for any savings or investment decision.
Real return = Nominal return − Inflation rate
| Nominal return | Inflation | Real return | Interpretation |
|---|---|---|---|
| 4.5% (term deposit) | 3% | 1.5% | Modest real gain |
| 3.0% (savings account) | 3% | 0% | Flat — no real gain |
| 2.0% (savings account) | 3% | −1% | Losing purchasing power |
| 8.0% (diversified index fund historical) | 3% | 5% | Strong real return |
| 10.5% (credit card interest you’re paying) | Any | — | Guaranteed real loss |
The “risk-free” illusion: A savings account earning 3% feels safe. But when inflation is 3%, that $10,000 buys the same goods in a year as the year before — you’ve earned nothing in real terms. After tax (PIE rate or marginal rate), the real return is often negative.
What Inflation Does to $10,000 Over Time
| Years | Inflation 2%/year | Inflation 3%/year |
|---|---|---|
| 5 years | Worth $9,050 in today’s dollars | Worth $8,590 |
| 10 years | Worth $8,190 | Worth $7,440 |
| 20 years | Worth $6,720 | Worth $5,440 |
| 30 years | Worth $5,520 | Worth $4,120 |
That $10,000 cash under the mattress for 30 years is worth only $4,120 in purchasing power at 3% inflation.
How Different Assets Perform vs Inflation
Cash and Savings Accounts
- Nominal rate (mid-2026): 3.0–4.5% at-call, 5.0–5.8% term deposits
- After PIE tax (28%): ~2.2–4.2% at-call, ~3.6–4.2% term deposit
- After inflation (~2.5%): Real return −0.3% to +1.7%
Cash and savings accounts barely keep pace with inflation in normal conditions. They are appropriate for short-term savings goals and emergency funds — not long-term wealth building.
Term Deposits
- 12-month rate (mid-2026): approximately 5.0–5.5%
- After PIE tax (28%): ~3.6–4.0%
- After inflation (~2.5%): Real return ~1.1–1.5%
Modest real returns. Appropriate for capital preservation with a defined time horizon (e.g., using money in 1–3 years). Not appropriate for money you’re investing for 10+ years.
KiwiSaver Growth Fund (Historical)
- Average annual return (10-year historical, growth funds): 8–11% nominal
- After fees (~1.0%): 7–10% nominal
- After inflation (~2.5%): Real return ~4.5–7.5%
KiwiSaver growth funds invested in diversified global equities have significantly outpaced inflation historically. Over a 30-year career, this compounding real return is the primary driver of retirement wealth.
NZX and Global Equities (Index Funds)
- NZX 50 historical return (10yr annualised incl. dividends): ~8–12%
- Global equities (MSCI World, 10yr): ~10–14% NZD
- After fees (~0.3–0.5% for index funds): 8–14%
- After inflation: Real return ~5.5–11%
Global diversification through low-cost index funds (Smartshares, Kernel, InvestNow) provides the highest reliable real returns over long time horizons.
The RBNZ’s Role
The Reserve Bank of New Zealand sets the Official Cash Rate (OCR), which influences all borrowing and deposit rates in NZ.
- OCR high (e.g., 5.5% in 2023): Higher term deposit rates, higher mortgage rates, suppressed inflation
- OCR low (e.g., 0.25% in 2020–21): Low deposit rates, low mortgage rates, risk of rising inflation
When the OCR drops (as it did in 2024–2025), savings account and term deposit rates follow down — making it harder to earn real returns from cash.
What to Do About Inflation
| Savings goal timeline | Appropriate asset | Real return potential |
|---|---|---|
| Under 1 year (emergency fund, near-term spending) | On-call savings account, term deposit | 0–1.5% real |
| 1–3 years (house deposit, medium goal) | Term deposit, conservative KiwiSaver fund | 1–2% real |
| 3–7 years | Balanced KiwiSaver or managed fund, index funds | 2–4% real |
| 7+ years (retirement, long-term) | Growth KiwiSaver, global index funds | 4–7% real |
The core principle: Keep only what you need in the near term in cash. Invest the rest in assets that outpace inflation over time.