How we measure
$5.

All purchasing-power calculations use the U.S. Bureau of Labor Statistics — CPI-U, All Items, Annual Average (1982-84=100). The Consumer Price Index for All Urban Consumers (CPI-U) is the U.S. government's headline measure of inflation, published monthly by the Bureau of Labor Statistics.

We use the annual average index value for each calendar year, on the 1982–84 = 100 reference base. Annual averages smooth out monthly volatility and give a fair "price level for the year" comparison.

Purchasing power is a ratio of price levels. If the CPI was 40.5 in 1971 and 322.4 in 2025, then prices rose by a factor of 7.96 over that span.

"The Purchasing Power of $5" plots, for every year from 1971 to today, how much money you would need now to buy what $5 bought in that year. The line falls toward $5 as it approaches today — that fall is the debasement of the dollar.

Hovering any year shows four figures: the nominal $5 then, its equivalent value today, the percentage of purchasing power retained, and the percentage lost.

1971 is the year the United States unilaterally ended the convertibility of the dollar into gold — closing the gold window and effectively ending the Bretton Woods system. It's a natural starting point for measuring the modern fiat dollar's purchasing power.

The "$5 vs. assets" engine compares purchasing-power erosion against the historical price of gold, Bitcoin, the S&P 500, wages, housing and more. These comparisons are hypothetical historical calculations — they describe what would have happened, not investment recommendations. They do not account for taxes, fees, transaction costs, bid/ask spreads, or execution differences.

Purchasing-power comparisons (CPI) and investment returns (assets) are always labelled separately and never conflated.

The most recent calendar year shown as a solid value is the latest official BLS annual average. Years not yet finalized by BLS are labelled est. and use a preliminary estimate based on available monthly CPI readings. They will be replaced with the official annual average when BLS publishes it.

The "What could $5 buy?" basket uses the U.S. Bureau of Labor Statistics Average Price Data (via FRED) as its primary source for milk, bread, eggs, ground beef, coffee and electricity. Those BLS series don't all start in 1971, however — they begin between 1978 and 1995 — so for earlier years FiveBucks draws on the original government publications that first published those same BLS average prices.

Each card shows the exact source for the year being displayed. When a year uses a secondary source, that source is named on the card — e.g. the U.S. Census Bureau's Statistical Abstract of the United States: 1972 for 1971 bread, hamburger and milk; the USDA's Food Cost Review, 1950–97 for milk in 1980 and 1990; the BLS Ground Chuck series for ground beef in 1980 (the "Ground Beef, 100% Beef" series begins 1984); and the U.S. Energy Information Administration for electricity in 1971. Gasoline (EIA) and movie tickets (NATO) are curated from their authoritative sources for every year.

These are all direct observations from official U.S. statistical publications — never estimates or interpolations. Where even these sources have no reliable figure for a given year and category, the card shows DATA UNAVAILABLE instead.

FiveBucks never fabricates numbers. Where a dataset is missing or a calculation cannot be made from an authoritative source, the interface displays DATA UNAVAILABLE rather than an invented figure.

The $5 Mortgage page isolates the effect of mortgage interest rates over time. It borrows a fixed $5 principal at each year's historical U.S. 30-year fixed mortgage rate and repays it over a full 30-year term (360 monthly payments). The amount borrowed never changes — only the rate does.

Source: Freddie Mac Primary Mortgage Market Survey (PMMS) — 30-Year Fixed Rate Mortgage Average in the United States, republished by FRED as series MORTGAGE30US. The survey begins April 1971 and is published weekly.

Annual aggregation: each year's rate is the arithmetic mean of all available weekly observations within that calendar year. Past years are treated as complete; the current year is computed from the observations published so far and labelled as partial — it is revised as new weekly readings arrive.

Monthly payment is calculated internally with the standard fixed-rate mortgage formula and is not displayed anywhere on the page:

The chart plots a single series — total paid over 30 years — against year. The mortgage rate appears only as supporting information in the hover tooltip; it is never plotted as a separate line and is never given a second axis.

Limitations: the PMMS rate is a survey of offered rates on conforming, conventional loans; it excludes fees, discount points, mortgage insurance, taxes and the actual underwriting cost of a real loan. The $5 principal is a fixed abstraction used only to isolate the effect of the rate — it is not a measure of affordability and is not lending advice.

The $5 Auto Loans page isolates the effect of new-auto loan interest rates over time. It borrows a fixed $5 principal at each year's historical U.S. 48-month new-auto finance rate and repays it over a full 4-year term (48 monthly payments). The amount borrowed never changes — only the rate does.

Source: Federal Reserve / G.19 Consumer Credit — Finance Rate on Consumer Installment Loans at Commercial Banks, New Autos, 48-Month Loan, republished by FRED as series TERMCBAUTO48NS. The series begins February 1972 and is published monthly.

Annual aggregation: each year's rate is the arithmetic mean of all available monthly observations within that calendar year. Past years are treated as complete; the current year is computed from the observations published so far and labelled as partial — it is revised as new monthly readings arrive. Missing observations are never estimated or invented.

Monthly payment is calculated internally with the standard fixed-rate amortization formula and is not displayed anywhere on the page:

The chart plots a single series — total paid over 4 years — against year, from 1972 to the latest available year. The auto loan rate appears only as supporting information in the hover tooltip; it is never plotted as a separate line and is never given a second axis.

Limitations: the G.19 rate is a survey of offered finance rates at commercial banks; it excludes fees, taxes, the cost of credit insurance and the actual underwriting cost of a real loan. The $5 principal is a fixed abstraction used only to isolate the effect of the rate — it is not a measure of affordability and is not lending advice.

The data layer is isolated from the presentation layer. Today it reads from a curated historical CPI series; the same interface is built to accept live API feeds and additional datasets — category-level inflation, food, energy, housing, wages, gold, Bitcoin, S&P 500, and future alternative inflation indexes — without changing any downstream calculation code.

• CPI measures urban consumer prices; it's an average, not any one household's experience.
• Annual averages hide within-year inflation swings.
• Past purchasing power does not predict future purchasing power.
• FiveBucks is an educational visualization, not financial advice.