Inflation and real returns
Real return is the only return that means anything. A 7% deposit against 6% inflation grows your money by 7% and your purchasing power by 0.94%. This page covers how to compute that properly — and why the usual subtraction shortcut is wrong.
Why you divide rather than subtract
Almost everyone computes real return as nominal minus inflation. It is a decent approximation at low numbers and it degrades badly as they rise.
The correct relation divides growth factors, because returns and inflation both compound:
real rate = ((1 + nominal) ÷ (1 + inflation)) − 1
| Nominal | Inflation | Subtraction says | Actually | Overstated by |
|---|---|---|---|---|
| 12% | 6% | 6% | 5.66% | 0.34 pts |
| 10% | 6% | 4% | 3.77% | 0.23 pts |
| 7% | 6% | 1% | 0.94% | 0.06 pts |
| 15% | 10% | 5% | 4.55% | 0.45 pts |
| 12% | 10% | 2% | 1.82% | 0.18 pts |
| 8% | 7% | 1% | 0.93% | 0.07 pts |
The error is small in absolute terms and large in proportional terms exactly where it matters most. At 8% nominal against 7% inflation, subtraction claims 1% while the truth is 0.93% — about 7% too optimistic on a figure that is already marginal. Compound that error for twenty years and the projection is meaningfully wrong.
What inflation does to a corpus
Converting a future amount to today's money is simple division:
real = nominal ÷ (1 + i)years.
| Years out | At 4% inflation | At 6% | At 8% |
|---|---|---|---|
| 10 | ₹67.56 L | ₹55.84 L | ₹46.32 L |
| 15 | ₹55.53 L | ₹41.73 L | ₹31.52 L |
| 20 | ₹45.64 L | ₹31.18 L | ₹21.45 L |
| 25 | ₹37.51 L | ₹23.3 L | ₹14.6 L |
| 30 | ₹30.83 L | ₹17.41 L | ₹9.94 L |
At 6%, purchasing power halves in roughly twelve years. Thirty years out, ₹1 crore buys about ₹17.41 L of today's goods. The corpus did not shrink — the yardstick moved.
This is why "₹1 crore" as a retirement target is unreliable. It is a number, not a standard of living, and the two drift apart at exactly the rate of inflation.
What rate to assume for India
India's CPI inflation has averaged close to 6% over the past decade. The RBI operates a flexible inflation-targeting framework with a 4% target and a two-percentage-point band either side, so 2% to 6% is the mandated range — and realised inflation has spent plenty of time near the upper end.
6% is a defensible default. 5% is optimistic, 7% is cautious, and both are worth testing.
But your personal inflation is probably higher than the index. CPI is a basket of national average spending, heavily weighted to food and fuel. If your budget is dominated by urban rent, private school fees or private healthcare, those categories have historically risen faster than headline CPI. For an education or healthcare goal, modelling 8–10% is not pessimism.
Three conclusions that follow
1. A fixed deposit is not "safe" for long-term money. At 7% taxed at a 30% slab you keep 4.90%, which against 6% inflation is -1.04% real — negative. Your capital is protected in rupees and eroding in purchasing power. Safe from volatility, not safe from loss.
2. A flat SIP shrinks in real terms every year. ₹5,000 a month held constant for twenty years is worth ₹1.56K a month in today's terms by the end. Increasing the instalment with inflation is the minimum needed to stand still — which is the case for a step-up SIP.
3. Goals must be priced forward, not backward. "₹50 lakh for my child's education in 15 years" almost always means today's ₹50 lakh. At 6% that is ₹1.2 Cr in fifteen years, and at 8% education inflation it is ₹1.59 Cr. The goal planner applies this for you.
Questions people actually ask
What is a real return?
The return after removing inflation — what your money gained in purchasing power rather than in rupees. It is the only figure that tells you whether you can buy more than you could before.
Compute it as ((1 + nominal) ÷ (1 + inflation)) − 1, not by subtraction.
Should I use inflation-adjusted returns in every calculation?
For any goal more than about five years out, yes. Below that the distortion is small enough to ignore; beyond ten years it dominates.
The practical approach: project in nominal terms because that is what you will see on a statement, then read the real value beside it to sanity-check whether the plan is actually sufficient. Every calculator here shows both.
Does equity protect against inflation?
Over long periods, historically better than most alternatives — company revenues and earnings tend to rise with prices, so equity has some structural inflation pass-through.
Over short periods it is unreliable, and high inflation is frequently bad for equities in the near term because it raises rates and compresses valuations. Equity is an inflation hedge over decades, not over quarters.
Why does my calculator show a smaller real value than I expected?
Because dividing by (1 + i)years is harsher than intuition suggests. Compounding works against you in exactly the same shape it works for you — most of the erosion happens in the later years, which is precisely where your corpus is largest.
Where these numbers come from
- Reserve Bank of India — monetary policy framework, CPI data
- MoSPI — official Consumer Price Index series