Economy.mp2d

Your cities extract resources from the worked tiles around them. These resources are the source which powers your nation's economy. Here each of the three resources is described.
===Food Points===
Your population needs food to survive. Each citizen requires 2 food points per turn. Each Settler or population unit requires from its home city 1 food per turn in Anarchy, Despotism, Monarchy, Constitutional Monarchy, and Communism; 2 in Republic, Democracy, Theocracy, and Nationalism. Except for Grassland, all terrain tiles without a special resource yield less than 2 food points. They cannot feed the citizen working them unless they are irrigated.
Every city has a Grain Storage of stored food (not to be confused with the building called a Granary). Cities producing more food than they require accumulate the excess in their Grain Storage, while those producing less than they require deplete their Grain Storage. When food is needed but none remains, starvation kills Settlers and population units first, followed by citizens.
Excess food can increase the population: the city Grain Storage has a limited capacity, and when it reaches full the city grows by one citizen and the Grain Store starts again at empty. But since Grain Storage capacity increases with population, each growth in population is more costly than the last, making this mode of growth important only for small cities*. 
* Grain Store capacity is capped at a ceiling of 60. Very large cities working a majority of high-food tiles can thus begin using the Grain Store as an effective method of growth again.
There are 3 main buildings and 2 major wonders which enhance food production and/or population growth:
	Granary
cost:35 upkeep:1requires:Pottery		Harbor
cost:40 upkeep:1requires:Seafaring		Supermarket
cost:80 upkeep:3requires:Refrigeration
	Pyramids
cost:180 upkeep:0requires:Masonry		Commissariat of Agriculture
cost:150 upkeep:0requires:Communism
👉🏻 NOTE: In Despotism, any building or wonder that reduces tile corruption or induces celebration, will increase food output on Grassland, Wheat, Fish, Oasis, Elk, etc. Such buildings and wonders are numerous: Ziggurat, Chand Baori, Sphinx, Code of Hammurabi, Hanging Gardens, Angkor Wat, Mausoleum of Mausolos, Supreme Court, Totem Pole, Courthouse. 
===Production Points===
Shield upkeep. A production point is called a Shield. Every city generates at least one Shield per turn. Shields are first used to pay upkeep for units supported by the city; most units cost one shield per turn. Under autocratic regimes, each city supports a few shields of unit upkeep for free. If city production drops too low, units that cannot be supported are disbanded.
Production targets. After paying upkeep, extra Shields are applied towards the unit, building, wonder, or coinage, that is the city's currently selected production target. Just like food points accumulate in the city Grain Store and yield a citizen when it reaches full, shields accumulate into the production target until the cost of the target is paid. When completed, production targets appear in their city. Leftover shields are applied to the city's next production target.
Each nation chooses to build buildings, units, or wonders that their technology makes available. There are a few restrictions: 1) Each city can have only one of each building. 2) Some buildings require that others be built first. 3) Great Wonders can only be completed by one civilization per game. Be careful—the game gives you the freedom to produce units you cannot support and buildings whose upkeep you cannot afford, which will be disbanded immediately after completion. Note that Settlers and other population units not only take shields, but also 1 citizen out of your city's population. A city cannot build a Settler with its last citizen unless you enable this by adjusting the city's Options tab, in which case the city will be abandoned and turn into a Settler.
Changing production targets. You can change the production target of any city, but you will lose half the accumulated shields when switching from a building, unit, or wonder to one of the other two types. If you change to the same type, you will not lose accumulated shields. If you change production the turn immediately after completing an item, you won't lose any of the production points that were left over from that turn. 
👉🏻 Don't change production targets on the same turn after disbanding or recycling a unit into the production target, or those shields will be lost!! Change targets first and then disband, or, wait until the next turn. (This special rule prevents certain unsavory exploits.) 
Purchasing production targets. You can spend gold to force the completion of a production target early, by hitting the Buy button in the city dialogue, or "B" when hovering the mouse over the city on the map. 
The gold cost varies by what type of thing you're buying off.
* The gold cost for units is: Gold = 2P+P2/20, where P = remaining shields needed. 
* The cost for buildings is Gold = 2P,
* The cost for wonders is Gold = 4P. 
In other words, there are different "exchange rates" between gold and shields for buying off production targets in the three different categories. Gold gets the best exchange rate at making buildings, and Shields get the best exchange rates at making units, particularly units with many production points remaining before completion. 👉🏻 A wise leader will consider this when deciding where to spend gold and where to allow raw production to complete itself.
Rush purchases: Costs are multiplied by two if production on an item hasn't started yet (that is, if there are zero accumulated shields.)
Coinage. Should you need gold instead of production points, you can direct cities to mint Coinage. Instead of producing a building or unit, the city will use its labor to convert its production points to mint gold coins. The base rate is 1.50 gold per each shield targeted into Coinage. For non-communist governments, a Marketplace, Bank, or Stock Exchange will each add 0.25 to the exchange rate of shields-to-gold. A Stock Exchange needs the tech The Corporation before its coinage bonus takes effect.
==== Increasing production through industrialization ====
Several buildings give bonus production, yielding more shield output. Each city can only use one of the four main Power Plants (that is, only one Coal Plant, Hydro Plant, Nuclear Plant, or Fusion Reactor). On the other hand, Solar Plants and Wind Plants can support and co-exist with any other power plants.
	Factory
cost:140 upkeep:4requires:Industrialization		Offshore Platform
cost:120 upkeep:3requires:Miniaturization		Mfg. Plant
cost:220 upkeep:6requires:Robotics
	Coal Plant
cost:120 upkeep:4requires:Refining		Hydro Plant
cost:175 upkeep:3requires:Electronics		Nuclear Plant
cost:120 upkeep:2
requires:Nuclear Power
	Solar Plant
cost:150 upkeep:-3requires:Environentalism		Wind Plant
cost:60 upkeep:-3requires:Environentalism		Fusion Reactor
cost:700 upkeep:0requires:Fusion Power
The wonders King Richard's Crusade and Hoover Dam also affect production. (Courthouse, Eiffel Tower, Supreme Court, Temple of Artemis, and Recycling Center may give a minimal bonus on production.) In Despotism, any building or wonder which reduces tile corruption can also increase production, if a city is working a tile resource which normally produces 3 or more shields.
====Work Lists====
When a city completes a unit, it normally starts producing another of the same type, and after completing a building or wonder, chooses a different one to build. New cities start work upon the best available defensive unit. Often you will instruct the city to work on something else instead, but this wastes time and attention if you already know the next several items the city should produce. In this case you should access the work list for that city and specify several products in sequence. The city will produce them in the order specified.
===Trade Points===
Trade reflects overall wealth generated in each city. Some trade points may be lost to corruption, which varies among forms of government and increases with distance from your capital city. Each city divides its remaining trade points into three items: Gold, Luxury, and Science. The amount given to each is controlled by the Tax Rates you select for each. Obviously, gold gives money for spending, and science helps research new technology. Luxury controls citizen happiness, which can avoid disorder and unlock unique bonus effects for each different form of government.
You may alter your tax rates on any turn. In MP2D you can adjust taxes in multiples of five percent. Most forms of government have limits to the maximum rates that you can set.
Buildings and Wonders affect trade directly, or indirectly by affecting corruption:
	Palace
cost:70
	Ecclesiastical Palace
cost:70Mysticism
	Courthouse
cost:45 upkeep:1Code of Laws
	Supreme Court
cost:200Literacy
	Colossus
cost:100Bronze Working
	Appian Way
cost:100The Wheel
	Marco Polo's Embassy
cost:400Trade
	Voyage of Darwin
cost:200Railroad
	Mausoleum of Mausolos
cost:100Ceremonial Burial
Notes: Ecclesiastical Palace functions as a Palace. Voyage of Darwin functions identically to Colossus. The Supreme Court functions as a Courthouse in every city in your nation. Marco Polo's Embassy increases Trade by +40% in every city in your nation.
===Trade Routes===
Trade Routes are potent. A trade route provides a significant boost to a city's trade.
Besides gaining trade from city tiles, you can increase trade by doing "Establish Trade Route" between cities. This is done by creating a Commerce Unit and sending it to a foreign city at least 15 tiles distant*, then establishing the trade route. Examples of Commerce Units are Trireme, Goods, Caravan, Galley, Freight, Cargo Ship.
* Manhattan Distance
One-time revenue. The nation who sent the Commerce Unit immediately gets one-time gold revenue upon establishing the route. Transportation techs (Railroad and Flight) decrease the premium for goods delivery, reducing one-time revenue; however, cities are usually larger with more trade at this point, so they still receive a healthy one-time bonus. Early capital trade bonus: Before Banking is discovered, a Trade Route established from your capital will give you a 4x bonus to one-time revenue. This represents the importance of having at least some trade, for small developing economies of the ancient world. 
* Note: the base gold bonus for one-time revenue is about 4x more than mp2-brava.
Ongoing revenue. A Trade Route produces ongoing revenue for both cities, every turn. Ongoing revenue from a Trade Route benefits the origin and destination cities equally. Both cities will get trade revenue each turn. In MP2 rules, ongoing revenue depends on—and only on—the sum total trade of both cities. Quick-jump: Trade Revenue Calculator
City tile bonus. A city with a Trade Route also gets a permanent +1 trade bonus to its city center tile. This is base trade before other multipliers from Marketplaces, Wonders, etc., so can accumulate a significant long-term bonus to the city.
Inactive Trade Routes. Trade Routes produce no revenue if you are at war with the other nation, but re-activate when relations improve. This allows you to immediately establish a Trade Route instead of being stuck outside a city, vulnerable to capture, then later agree to ceasefire or diplomatic relations.
Maximum number of Trade Routes. Each city may have one Trade Route with a foreign city. This creates natural scarcity: there are only as many routes as there are cities to fill them. If you attempt to establish more routes, the first Trade Route will be replaced if its revenue is less than the new route. This means high trade cities can aggressively "muscle" their way into foreign cities by replacing the lesser Routes of other nations.
Eco-diplomacy. Trade Routes can be a political tool. You can offer them to a foreign nation, knowing that they will lose income if they go to war with you.
Importance of Trade Routes. In MP2D, extra trade income makes a significant return on investment (ROI), competitive with other top tier investments like Marketplaces and top-tier Wonders. Increased trade may be just enough to help a low trade city celebrate, keep the national luxury rate lower, or to gain diplomatic favor from another nation.
Other Bonuses
* A one-time 4× gold bonus is awarded for a new trade route from your capital, if done prior to any nation discovering Banking.
* Colossus increases trade route revenue to its home city, firstly because it creates more trade on tiles, but also by an extra boost to the trade revenue itself. 
* Appian Way gives +1 trade for all routes in the nation with 4 or more trade. This can go to +2 trade for routes with more than 8 trade, and so on.
To view the current Trade Route info in a city, click the Routes button inside the City screen.
=== Trade Revenue Calculator ===
Trade Route Revenue Formula
*TR: Trade revenue (trade points added to base trade.)
*C1BT: City1's base trade recorded before TC.
*C2BT: City2's base trade recorded before TC.
TR = [ 3 x (C1BT + C2BT + 4) / 12 ] x 35% rounded to nearest whole number
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