How to Use Our Inflation Calculator to Compare Prices Over Time
If you want to know what £1,000 in 2015 is actually worth today, you use an inflation calculator. In less than 60 seconds, you'll see how purchasing power has changed over time — whether prices have simply crept up (they have) or whether specific items have soared way beyond the rate of general inflation (they often do). This guide walks you through exactly how to use our inflation calculator to compare prices across different years and understand the real cost of living changes.
The inflation calculator is straightforward to use, but the real skill is knowing what to do with the results once you have them. That's what we'll cover here.
Why Comparing Prices with Inflation in Mind Actually Matters
Inflation is the percentage increase in the average price of goods and services over time. It doesn't feel abstract when you're at the supermarket — you notice it immediately. But when you're comparing salaries from different decades, house prices from years apart, or the "value" of money saved in the past, inflation is the invisible number that makes all the difference.
Here's the thing: if you had £50,000 in 2010 and you have £50,000 in 2026, you're not in the same position financially. That money will buy you less today because inflation has eroded its purchasing power. How much less? That's what the inflation calculator tells you.
In the UK, we measure inflation using the Consumer Prices Index including Housing (CPIH) — the Office for National Statistics' official measure. Over the last 15 years, inflation has ranged wildly: near zero in 2016, negative briefly during 2020, then spiking above 10% in 2022–2023 before cooling. That volatility means comparing any two figures from different years without adjusting for inflation can lead you badly astray.
The Bank of England targets 2% inflation as the long-term "normal." That doesn't mean things get cheaper — it means the pace of price rises is steady and predictable. When inflation overshoots that target, as it has in recent years, the hidden cost to savers and wage-earners is real.
How to Use the Inflation Calculator: Step by Step
Our inflation calculator is designed to be simple, but let's walk through the process so you can compare prices accurately.
What you need before starting:
- An amount of money (in pounds)
- A starting year
- An ending year
That's it. You don't need to be precise about the month — the calculator uses annual CPI data, so "2020" is all it needs.
Step 1: Enter the amount
Type the figure you want to compare. If you're looking at a historical salary, use the exact number (or your best estimate). If you're comparing house prices, enter the price you're thinking about. £1,000, £50,000, or £250,000 — the calculator scales to any amount.
Step 2: Select your starting year
This is the year you want to compare from. If you're asking "what was £30,000 worth in 2020 in today's money?", 2020 is your starting year.
Step 3: Select your ending year
This is the year you want to compare to. For most people, that's the current year, but you can compare any two years — 2010 to 2025, or 2015 to 2020, or any other pair.
Step 4: Click Calculate
The result appears instantly. You'll see:
- The original amount in the starting year
- What that amount is equivalent to in the ending year
- The total percentage increase due to inflation
- A year-by-year breakdown (so you can see which periods saw the biggest price jumps)
Step 5: Interpret the results
Let's say you find that £100 in 2015 is equivalent to £119 in 2026. That means inflation has eroded the value of money by about 19%. If someone was earning £25,000 in 2015 and is earning £25,000 now, they've effectively taken a 19% pay cut in real terms — even though their nominal salary hasn't changed. This is why comparing salaries across years with inflation in mind is so important.
Real-World Examples of Price Comparison Over Time
Let's put this into practice with concrete scenarios.
Checking if wages have kept up with inflation
You earn £35,000 today. A friend kept their salary history and shows you they earned £30,000 in 2015 — and they're curious whether they've earned more "real" money since then. Plug in: £30,000 (2015) → 2026. The calculator says £30,000 in 2015 is worth about £35,700 in today's money. So your friend's current salary of £35,000 is actually slightly behind inflation — they should have earned £35,700 just to keep pace. It's a sobering reminder that a pay freeze in nominal terms is actually a pay cut in real terms.
Understanding house-price inflation
House prices and general inflation don't move together. A house that cost £150,000 in 2010 might be worth £350,000 today. But how much of that is "real" appreciation vs. simple inflation? Plug in: £150,000 (2010) → 2026. General inflation says that £150,000 should be worth about £190,000 in 2026 money. If the house is worth £350,000, that's a real gain of £160,000 beyond inflation — or you can say property has appreciated about 84% in real terms. That's why using a mortgage calculator alongside inflation analysis gives you the full picture on house affordability. Or if you're deciding between renting and buying, comparing the two options needs to factor in inflation too.
Checking the real value of savings
You inherited £15,000 in 2015 and left it in a savings account earning 0.5% interest (not uncommon for savings rates then). You never added to it. How much real purchasing power did you lose? First, use the inflation calculator: £15,000 (2015) → 2026 tells you that you'd need about £17,850 just to have the same purchasing power. With 0.5% interest, you probably have around £15,750 today. That's a real loss of about £2,100 in purchasing power — which is exactly why planning savings goals with inflation in mind matters so much. You need your savings to grow faster than inflation, or the money is quietly disappearing.
Comparing loan costs across time
If you took out a £10,000 personal loan in 2015, the actual cost in today's money looks different. Plug in: £10,000 (2015) → 2026 and you'll see that amount is now worth about £11,900 in 2026 money. So the real interest cost you paid back then was actually smaller than it looks in nominal terms. This is why understanding APR on different loan products requires context — the same percentage rate hits harder when inflation is low and softer when inflation is high.
Tips for Comparing Purchasing Power Like a Pro
1. Separate "nominal" from "real" changes
Nominal = the number on the payslip or the price tag. Real = adjusted for inflation. A salary rise of 3% is great if inflation is 2%, but it's a pay cut if inflation is 5%. Always ask both questions.
2. Remember that inflation isn't uniform
General inflation (measured by the Consumer Prices Index) averages across thousands of goods and services. But your inflation — the price rises for the things you actually buy — might be very different. House prices, energy bills, and food costs can rise much faster or slower than the national average. The calculator gives you the official inflation adjustment; the real picture also depends on your specific spending.
3. Use the year-by-year breakdown to spot shocks
The calculator shows you the breakdown by year. This is where you'll see the big jumps — the 2008 financial crisis, the 2020 pandemic shock, the 2022–2023 energy-price spike. Understanding when inflation hit helps you make sense of specific financial decisions from that period.
4. Compare multiple scenarios
Try a few variations. What was £40,000 in 2010 worth in 2020? What was it worth in 2026? Seeing the pattern helps you understand long-term erosion vs. short-term spikes.
5. Think about inflation when planning ahead
If you're planning a retirement date, remember that your target income today will need to be higher in real terms when you retire. If you're saving for a first-time house purchase, keep in mind that inflation affects both your savings growth and the target house price — they both move, usually at different rates.
Frequently Asked Questions
Q: What's the difference between CPIH and RPI?
A: The UK publishes two main inflation measures. CPIH (Consumer Prices Index including Housing) is the official national statistic and what we use in our calculator. RPI (Retail Prices Index) is older, often runs higher, and is used mainly for historical data and specific uprating (like rail fares). For modern comparisons, CPIH is the one to use.
Q: If inflation is 2%, does that mean prices go up exactly 2%?
A: No. A 2% inflation rate is an average across the whole economy. Some things (like energy or groceries) might go up 5%, while others (like electronics) might go down. The 2% is the weighted average. That's why checking actual price changes for things you buy matters alongside the overall inflation figure.
Q: Can I use the inflation calculator to predict future prices?
A: No — we only use historical inflation data. We can't predict the Bank of England's interest-rate decisions or supply shocks or anything else that drives future inflation. Use the calculator for historical comparisons only. For planning, you can assume an average inflation rate going forward (maybe 2%), but that's a guess, not a prediction.
Q: Should I factor in inflation when planning retirement?
A: Absolutely. If you're planning to live on £30,000 a year in retirement 20 years from now, you need to account for what £30,000 will actually buy then. This is where the inflation calculator becomes crucial for retirement planning — it forces you to think in real terms, not nominal.
Q: Does the calculator include house prices in the inflation measure?
A: CPIH includes a measure of housing costs (specifically, owner-occupier housing costs), not house prices themselves. So the "house" part of inflation is about the cost of living in a house (mortgage interest, council tax, repairs, utilities), not capital appreciation of property. If you're trying to adjust house prices for inflation, you need to use the general CPIH figure and remember that house prices typically move independently of general inflation.
Q: What if I want to compare prices from outside the UK?
A: Our calculator uses UK inflation data (ONS CPIH). If you need to compare a period when the UK wasn't in the EU or when currency rates were very different, you might need a historical currency converter and an inflation calculator — they're separate questions.
Q: How do salary rises and inflation work together?
A: If you get a 3% salary rise and inflation is 2%, you've gained 1% in real purchasing power. If you get a 3% rise and inflation is 4%, you've actually lost 1% in real terms (even though the number on your payslip went up). The inflation calculator helps you figure out what your salary is actually worth in real terms across different time periods.
Q: Can I use the results to argue for a pay rise?
A: The inflation calculator gives you facts. If you've earned the same nominal salary for 3 years and inflation has been 8% in that period, the calculator proves you've lost 8% in real purchasing power. That's a solid conversation-starter with your employer. But "I've lost real value" is different from "I deserve more" — that's a negotiation. The calculator is your evidence, not your argument.