Inflation is the only financial force that affects literally everyone, yet most people never run the numbers on it. Prices rising 'a few percent a year' sounds gentle. Compounded over the decades you'll be saving and retired, it is anything but.
The quiet halving
At 3% inflation, prices double roughly every 24 years — which means money doubles in cost, or equivalently, cash halves in buying power. The 1,000 in a drawer today buys about 550 worth of today's goods in 20 years. Nothing was stolen; every unit is still there. It just buys less. That's why economists describe inflation as a tax on cash: it transfers purchasing power away from anyone holding money that isn't growing.
The rule of 70 gives you the quick math: divide 70 by the inflation rate to get the doubling time. At 2% that's 35 years; at 5%, just 14; at 10% — a rate many countries have lived through recently — prices double in only 7 years.
Real returns are what count
A savings account paying 2% while inflation runs 3% has a real return of roughly minus 1%: the number on the statement grows while the value shrinks. Every financial decision — savings rates, salary negotiations, loan rates, retirement targets — should be judged after inflation. A raise below inflation is a pay cut with better manners.
This is also the honest case for investing at all. Nobody would bother with market risk if cash held its value. Cash is for emergencies and near-term goals precisely because it's stable over months; it's dangerous over decades because it's guaranteed to shrink.
Planning in future money
The most common planning mistake is stating long-term goals in today's prices. A retirement income of 30,000 sounds fine — but if it's 25 years away at 3% inflation, the equivalent figure is about 62,800. Pension pots, education funds, and 'how much house can we afford someday' all need the same translation.
Our inflation calculator does this both directions — what today's amount will cost in the future, and what today's cash will be worth — with a year-by-year table you can download. Pair it with the compound interest calculator to check whether your savings rate actually outruns rising prices. That single comparison — growth rate versus inflation rate — is the entire game of long-term saving in one line.
Mistakes people make when thinking about inflation
Assuming a single 'headline' inflation figure applies equally to your own spending is a common one — housing, healthcare, and education have often risen faster than the general basket, so your personal inflation rate may be higher than the published average.
Treating a fixed-rate loan as a hedge people forget about is another oversight worth remembering the right way: fixed debt actually benefits from inflation, since you repay it in money that's worth less over time — a small silver lining worth factoring into how aggressively you pay down low-rate, fixed debt versus investing instead.
Reacting to short bursts of high inflation by overhauling a long-term plan is a third — a single volatile year matters far less to a 20-year plan than the average rate over the whole period, so avoid making irreversible decisions based on one bad print.