Fun little project to look at what our countries biggest purchases would cost adjusted for todays dollars. In Florida alone there are homes being purchased for more than the entire state would’ve cost even when adjusted for inflation.

Using current U.S. CPI inflation data and widely reported historical purchase amounts. The numbers are approximate, but they give a good sense of how big each deal was in today’s dollars.

Inflation-adjusted cost

PurchaseOriginal priceRough cost in today’s dollarsPerspective
Louisiana Purchase$15 millionabout $418 million to $430 millionStill a huge land bargain for a territory that reshaped the country
Florida (from Spain)$5 millionabout $120 million to $130 millionRoughly the price of a mid-size sports team sale or a luxury downtown tower, not a state-sized territory.
Mexican Cession$15 millionabout $590 million to $650 millionThat is still cheap for a massive swath of the Southwest and West
Gadsden Purchase$10 millionabout $250 million to $260 millionA small slice of land, but strategically important; today that’s still modest for major infrastructure or real estate deals
Alaska Purchase$7.2 millionabout $150 million to $160 millionAbout the cost of a single high-end Manhattan office building, for an entire future state
Danish Virgin Islands$25 millionabout $550 million to $600 millionComparable to a sizable modern corporate acquisition, but for an overseas territory

Perspective

The Louisiana Purchase looks especially dramatic in hindsight because the U.S. bought an enormous fraction of the continent for an amount that would still be below the price of many modern urban development projects. Alaska is the standout bargain on a per-acre basis: in today’s dollars, the whole deal is roughly in the low hundreds of millions, which is astonishing for such a huge, resource-rich territory.

Florida, the Mexican Cession, the Gadsden Purchase, and the Virgin Islands were all relatively small cash outlays by modern standards, especially considering the land and strategic value involved. Put another way, the U.S. was often buying geography for less than many companies now spend on a single acquisition, headquarters campus, or major construction project.

Important note

These are inflation-adjusted estimates, not exact “one true” present-day values, because the inflation calculator depends on the base year and the index used.