Economy

Civilization 4's economy runs on commerce, which a slider splits between research (100% at the start), gold, culture after Drama and, in Beyond the Sword, espionage; gold pays city maintenance (rising with the number of cities and their distance from the Palace), civic upkeep, unit support and inflation. Courthouses halve a city's maintenance, and trade routes, cottages and Markets raise income.

Civilization 4's economy starts with commerce, which every city collects from its tiles and trade routes and which one slider splits between research and gold (research starts at 100%), with culture added once you know Drama, per the base game's manual (pp. 26, 67), and espionage added after Writing in Beyond the Sword. The gold pays for city maintenance, which grows with the number of cities and their distance from the Palace, for civic upkeep, for unit support and for inflation; whatever is left funds hurrying and diplomacy. Expanding faster than income grows is the classic way to stall: the manual warns that it "will drain your treasury of gold and reduce the rate at which your civilization conducts research". Cities and their tiles are covered on Cities; the civics that change these costs are on Civics.

3D map of grassland crossed by brown roads and blue rivers, small towns and farms, groups of units with yellow banners, and a label at the top reading Tiwanaku, The Great Wall. — Gameplay from the Warlords Steam page: towns and fields linked by roads across green land and rivers, with a city named Tiwanaku building The Great Wall. Firaxis Games and 2K

Quick facts

Slider	Research (100% at the start) and gold; culture after Drama; espionage after Writing (Beyond the Sword)
City maintenance	Number of cities plus distance from the capital; the capital starts at 0
Beyond the Sword maintenance	Adds corporations and overseas cities as third and fourth factors
Courthouse	-50% maintenance in its city
State Property	No distance maintenance
Civic upkeep	None, Low, Medium or High, scaled by cities and population; Organized leaders pay half
Trade routes	1 per city at first; foreign routes pay more and need Open Borders
Running short	The game lowers the research rate to what you can afford, never raises it

Source: Civilization IV manual, pp. 26, 67-68, 83, 155-156, 159; Beyond the Sword manual, pp. 13, 23.

Commerce and the slider

Commerce comes from the land and from trade: river tiles, coast, cottages, gold and gem mines and trade routes all add it, per the base manual (p. 53). The investment percentages then split each city's commerce between research and gold, and later culture, and the shares cannot pass 100% together. Only commerce from your cities can become research: gold from trading, pillaging and looting, and merchant activities goes straight into the treasury, per the base manual (p. 67).

The manual's worked example shows how buildings and specialists stack on top of the slider. A city with 30 commerce at 80% research, with a Library (+25%) and one Scientist (+3), makes 6 gold and (24 + 3) x 1.25 = 33.75 research, per the base manual (p. 157). Percentage buildings multiply the share after the slider, so a Library adds nothing to gold and a Market nothing to research.

Culture arrives with Drama, and every 10% of commerce put into it adds one happy face in every city (more with Theaters, Colosseums and Broadcast Towers), per the base manual (pp. 26, 157). Beyond the Sword added an espionage slider once Writing is known, per the Beyond the Sword manual (p. 13); see Espionage.

City maintenance

Every city except the capital costs gold each turn, from two sources: its distance from the capital and the total number of cities you own, according to the base manual (p. 156). The city screen's maintenance figure shows each city's cost, and a tooltip shows which part comes from which source. The capital starts at 0.

Beyond the Sword added two more factors: corporations in a city, and "Overseas Maintenance" for cities on a continent that does not hold your capital, which grows with the number of cities there until they cost more than they make, per the Beyond the Sword manual (p. 23). Those cities can be released as a Colony, a separate civilization that becomes your vassal; see Diplomacy.

The fixes are buildings, a wonder and a civic. Each Courthouse halves its city's maintenance; enough Courthouses unlock the Forbidden Palace, a second capital that controls distance costs around it; and the State Property civic removes distance maintenance entirely, per the base manual (p. 156). The Warlords manual's charts (p. 135) put the Forbidden Palace at 6 Courthouses and 8 or more cities, and the Versailles wonder also reduces maintenance in nearby cities. A city celebrating "We Love the King" pays no maintenance that turn. In Warlords, vassals raise the master's maintenance for its own cities, more with more vassal cities, per the Warlords manual (p. 13).

Why maintenance replaced corruption

Soren Johnson, the lead designer, wrote that corruption and waste were "never coded" in Civilization 4. In his afterword in the base manual (p. 177), he explains that Civ III's heavy corruption did stop "Infinite City Sprawl" but became that game's top complaint, and that charging upkeep for buildings punished developed cities instead of the small ones of a sprawl strategy. So the cost moved to the city itself: a flat charge per city that rises with empire size, so that small undeveloped cities become a net loss.

To keep that from being "unfun", the team paired it with a reason to build fewer, larger cities, city specialization, which the afterword (p. 178) ties to resources, specialists and national wonders. The base manual's own early chapter (p. 46) still calls the distance cost "corruption" and mentions a "National Property" civic, wording from earlier in development; its advanced rules (p. 156) and Johnson's afterword describe the maintenance that shipped.

Civic upkeep, units and inflation

Civics cost upkeep at one of four levels (none, low, medium, high), and the gold cost of each level grows with your number of cities and your population, per the base manual (p. 83). The manual advises checking the Financial Advisor (F2) before switching to an expensive civic. Organized leaders pay 50% less civic upkeep, per the base manual (p. 159).

Units also cost gold to support, depending on the size of your civilization and your civics, and the manual suggests disbanding units when money runs short, per the base manual (p. 39). Pacifism adds support cost per military unit and Vassalage lowers it.

Inflation raises costs as the game goes on. The base manual (p. 167) says maintenance, civic costs and inflation all increase with difficulty, giving "a much more strained budget on the higher difficulties"; it does not give the inflation rate, which the Financial Advisor shows in game. See Difficulty Levels.

Trade routes

Trade routes form on their own between cities, each city taking the most profitable routes it can, and each adds base commerce to its city: three routes of 10 commerce each add 30, per the base manual (p. 155). A city starts with one route; techs, buildings, wonders and civics add more. Routes to foreign cities pay more than domestic ones but need an Open Borders agreement, and international trade is traced from your capital to the other civilization's capital.

The routes need a path. GameSpot's walkthrough says Sailing allows trade along coasts and Astronomy across the ocean, and Beyond the Sword requires Sailing for trade along rivers and lets ships blockade and plunder enemy routes, per the Beyond the Sword manual (pp. 24-25). Route income rises with the Harbor (+50%) and the Temple of Artemis (+100%); extra routes come from Free Market (+1 per city), the Great Lighthouse (+2 in coastal cities) and, after patch 1.61, Castles (+1 until Economics), per the Warlords manual's charts and updates. Mercantilism gives a free specialist per city but forbids foreign routes.

Raising income

The base manual's own list for more income is cottages and mines, roads that join cities into trade routes, Courthouses, Markets and Harbors, temples to put unhappy citizens back to work, and civics, per the base manual (p. 53). Gold buildings stack: the Market and Grocer add 25% each and the Bank 50%, and Wall Street doubles one city's gold, per the Warlords manual's charts. Financial leaders get +1 commerce on every tile already making 2 or more, and a Golden Age adds +1 commerce to every worked tile that already makes commerce, per the base manual (pp. 94, 159). The choice between cottage commerce and specialists is on Cottages and Specialists.

Bureaucracy adds 50% production and commerce in the capital, which GameSpot's walkthrough calls strong for smaller civilizations and in the early game. How to pace early expansion against maintenance is on Early Game Strategy.

Spending gold

Gold pays maintenance, upkeep and unit support first, then whatever you choose: hurrying production under Universal Suffrage, and buying techs, resources or peace in diplomacy. The Kremlin cuts hurry costs (by 33% after patch 1.61, per the Warlords manual, p. 104).

Going broke

When the treasury cannot cover the current research rate, the game lowers the rate to the highest it can afford, and it never raises it again by itself, per the base manual (pp. 67-68). Gold-per-turn deals are owed "no matter what: empty treasury, anarchy, etc.", and the base manual (p. 103) says the treasurer disbands units as needed to pay them. The manuals describe no other rule for an empty treasury and never use the word "strike"; the Financial Advisor (F2) shows the running balance in game.

Frequently asked questions

How does the science slider work in Civ 4? In Civilization 4 the slider splits each city's commerce between research and gold (research starts at 100%), with culture added after Drama and espionage after Writing in Beyond the Sword, per the base manual. Buildings such as the Library multiply the research share after the split.

How is city maintenance calculated in Civ 4? Civilization 4 city maintenance comes from each city's distance to the capital and the total number of cities you own; Beyond the Sword adds corporations and overseas cities, per the Beyond the Sword manual. Courthouses halve it and State Property removes the distance part.

Why am I losing money in Civ 4? Civilization 4 costs rise with every new city, every civic above no upkeep and every unit you support, and inflation and difficulty push them higher. The base manual warns that expanding "too far too fast" drains the treasury; Courthouses, cottages, trade routes and a lower research rate are the fixes.

What happens if you run out of gold in Civ 4? In Civilization 4 the game lowers your research rate to what you can afford, and if you owe gold per turn in a deal, your treasurer disbands units to pay it, per the base manual. The manuals describe no other penalty.

How do trade routes work in Civ 4? Civilization 4 trade routes form automatically, one per city at first, and add commerce to their city; foreign routes pay more but need Open Borders, per the base manual. Harbors, Free Market, the Great Lighthouse and the Temple of Artemis add routes or income.

Is there corruption in Civ 4? No. Soren Johnson wrote in the Civilization 4 manual's afterword that corruption and waste were "never coded"; a per-city maintenance cost that grows with empire size replaced them, per the base manual.

What does inflation do in Civ 4? Civilization 4 inflation raises your costs over time, and the base manual says it, maintenance and civic costs all increase with difficulty. The manual gives no rate; the Financial Advisor (F2) shows it.

Sources

Sid Meier's Civilization IV manual (with Soren Johnson's "Afterwords"), 2K Games and Firaxis Games, 2005, read Oct 21, 2026
Civilization IV: Warlords manual, 2K Games and Firaxis Games, 2006, read Oct 21, 2026
Civilization IV: Beyond the Sword manual, 2K Games and Firaxis Games, 2007, read Oct 21, 2026
Civilization IV Walkthrough, GameSpot (Doug Radcliffe), Jan 18, 2006, read Oct 21, 2026