$5,000 in 5 years at 3% inflation
Projected using a flat, user-assumed average annual inflation rate — not actual historical CPI data. Use the calculator below to try your own amount, time span, or rate.
Future Cost After 5 Years
$5,796.37
Cumulative Inflation
15.93%
Purchasing Power of $5,000.00 Today, in 5 Yrs
$4,313.04
Example
At an assumed 3% average annual inflation rate, something that costs $5,000.00 today would cost approximately $5,796.37 in 5 years — a cumulative increase of 15.93%. That same $5,000.00, if simply held as cash rather than invested, would only be able to buy about $4,313.04 worth of today's goods by then.
What is an Inflation Calculator?
An inflation calculator projects how the cost of goods and services — or, equivalently, how the purchasing power of a fixed amount of cash — changes over time as prices rise. Enter a starting amount, a number of years, and an assumed average annual inflation rate, and the calculator compounds that rate forward to show both the future dollar cost of something that costs that amount today, and how much real buying power the same amount of cash would lose if simply held rather than spent or invested.
Important scope note: this tool does not look up actual historical U.S. Consumer Price Index (CPI) data — there is no "what would $100 in 1990 be worth today" lookup here, because that requires a real historical CPI table. Instead, it uses a flat, user-specified average annual rate (defaulting to roughly the long-run U.S. historical average of about 3%) and compounds it forward or backward like interest. This makes it well-suited for forward-looking "what if" planning — retirement budgeting, long-term savings goals, pricing assumptions — but if you need the actual measured inflation between two specific past years, an official CPI table such as the one published by the U.S. Bureau of Labor Statistics (bls.gov) is the more accurate source.
Future cost vs. today's nominal amount, year by year
Year-by-Year Inflation Schedule
| Year | Future Cost | Today's Nominal Amount | Cumulative Increase |
|---|---|---|---|
| 0 | $5,000.00 | $5,000.00 | 0% |
| 1 | $5,150.00 | $5,000.00 | 3% |
| 2 | $5,304.50 | $5,000.00 | 6.09% |
| 3 | $5,463.64 | $5,000.00 | 9.27% |
| 4 | $5,627.54 | $5,000.00 | 12.55% |
| 5 | $5,796.37 | $5,000.00 | 15.93% |
How Is Future Cost Calculated?
This calculator compounds an assumed average annual inflation rate forward over the number of years you enter, the same way compound interest grows a savings balance — except here it grows the cost of goods instead of the value of money.
- Starting Amount — today's price or amount of cash
- r — assumed average annual inflation rate, as a decimal
- n — number of years
The purchasing-power figure runs the same formula in reverse — dividing the starting amount by the same growth factor — to show what a fixed sum of cash, left un-invested, would be able to buy in today's terms after that many years of erosion.
What is Inflation?
Inflation is a general, sustained increase in the prices of goods and services across an economy, which corresponds to a fall in the purchasing power of a currency — each unit of money buys a little less than it did before. It's normal for individual prices to rise and fall for their own reasons (a bad harvest, a new competitor), but inflation refers to the broad, economy-wide trend measured across a large basket of goods and services, not any single price.
Most developed economies, including the United States, experience mild, ongoing inflation most years rather than either stable prices or deflation. Historically, U.S. inflation has averaged somewhere in the neighborhood of 3% per year over long multi-decade stretches, though any given year can run well above or below that average — which is exactly why this calculator treats the rate as an assumption you supply rather than a fixed constant.
What is CPI and How Is It Measured?
In the United States, the primary real-world measure of inflation is the Consumer Price Index (CPI), published monthly by the Bureau of Labor Statistics (BLS). The BLS tracks the prices of a large, fixed "basket" of goods and services that a typical urban household buys — everything from groceries and rent to medical care and gasoline — and weights each category by how much of a typical household's spending it represents, so a change in gas prices moves the index more than an equivalent percentage change in, say, postage stamps.
The year-over-year inflation rate is then simply the percentage change in that index between two points in time. This calculator does not pull those real CPI figures — it has no historical database to query — so any rate you enter here is your own assumption, not a measured BLS statistic. For a real historical comparison (for example, "what would $500 in 2010 be worth today"), the BLS's own CPI inflation calculator or published CPI tables are the authoritative source.
Why Compounding Matters Over Long Periods
Because inflation compounds year over year — each year's price increase is applied on top of the already-inflated price from the year before, not on the original starting price — its effect accelerates the longer the time horizon runs. A 3% annual rate barely changes prices over a single year, but compounded over 30 years it multiplies the cost of something by roughly 2.4 times, and compounded over 50 years it more than quadruples it.
This is also why central banks, including the U.S. Federal Reserve, generally target a modest positive inflation rate — commonly cited as around 2–3% — rather than 0%. A small, predictable amount of inflation encourages spending and investment over hoarding cash (since idle cash slowly loses value) and gives the central bank room to cut interest rates during downturns without hitting zero. The tradeoff is that even "healthy" inflation steadily erodes the real value of money that isn't earning a return — which is precisely what the purchasing-power figure in this calculator illustrates.
Example — Your Current Inputs
At an assumed 3% average annual inflation rate, something that costs $5,000.00 today would cost approximately $5,796.37 in 5 years — a cumulative increase of 15.93%. That same $5,000.00, if simply held as cash rather than invested, would only be able to buy about $4,313.04 worth of today's goods by then.
Additional Example — A $4 Cup of Coffee
Suppose a cup of coffee costs $4.00 today. At an assumed 3% average annual inflation rate, that same cup of coffee would cost approximately $5.38 in 10 years, $7.23 in 20 years, and $9.71 in 30 years — even though nothing about the coffee itself changed. This is a useful everyday illustration of why a fixed retirement income or a static price list can quietly lose value over a long enough horizon: the coffee doesn't get better, but the number of dollars needed to buy it keeps climbing.
About These Parameters
- Starting Amount
- This can represent either the price of a specific good or service today (a car, a year of college tuition, a grocery bill) or simply a sum of cash you're holding. The calculator treats both the same way: it projects what that amount will need to grow to, in future dollars, to keep pace with the inflation rate you enter. A realistic value could be as small as a few dollars for an everyday item or in the tens of thousands for a major purchase or a full year of expenses.
- Number of Years
- The length of the projection window. Inflation's effect is small over a year or two but compounds meaningfully over a decade or more, so this field has an outsized effect on the result — doubling the number of years does not just double the cumulative inflation, it compounds on top of itself. Common horizons are 5–10 years for near-term planning and 20–30 years for retirement or long-term savings goals.
- Average Annual Inflation Rate
- This is an assumption you supply, not a number looked up from historical CPI records — there is no historical CPI database behind this calculator. The default of 3% reflects a commonly cited long-run U.S. average, but actual year-to-year inflation has ranged from near zero (or briefly negative) to double digits depending on the economic period. Try a range of rates (for example 2%, 3%, and 5%) to see how sensitive your projection is to this assumption, especially over longer time horizons.
Frequently Asked Questions
Does this calculator use real historical inflation data?
No. This calculator uses a flat, user-specified average annual inflation rate that you enter, compounded forward or backward like an interest rate. It does not query any historical Consumer Price Index (CPI) table. If you need the actual measured inflation between two specific past years — for example, "what would $1,000 in 2005 be worth in 2025 dollars" — an official CPI table, such as the one published by the U.S. Bureau of Labor Statistics, is the accurate source, since real historical inflation varied considerably from year to year rather than following a single constant rate.
What inflation rate should I assume?
A commonly used baseline is about 3%, roughly matching the long-run historical U.S. average, and the default on this calculator. For conservative retirement or long-term planning, some people run the numbers at a slightly higher rate (4–5%) to stress-test their plan against a higher-inflation environment. There's no single "correct" rate — trying a low, medium, and high estimate side by side gives a more realistic range than relying on any single number.
What's the difference between "future cost" and "purchasing power"?
"Future cost" answers: how many dollars will it take, in the future, to buy what today's starting amount buys right now? "Purchasing power" (or real value) answers the mirror question: how much of today's goods could that same starting amount of cash — left un-invested — actually buy once you get to that future year? Both numbers describe the same erosion from two different directions: one grows the price tag, the other shrinks the buying power of a fixed pile of cash.
How can I protect savings from inflation?
Cash sitting idle, especially in a low- or no-interest account, is the asset most exposed to inflation, since its nominal value never changes while its real value steadily shrinks. Assets that have historically grown faster than inflation over long periods — investments in a diversified portfolio, inflation-protected securities like U.S. TIPS, or an interest-bearing account whose rate at least keeps pace — can help offset this erosion, though every option carries its own risk and return tradeoffs that are beyond what this calculator models.