I always wonder what are the differences as levels increase. The obvious is that higher levels get harder, but why. What makes them harder. I have put together that information here. I did not list every entry, because some of them were not clear, and other did not seem to be overly relevant. Obviously, if you just relay on the table below you will have a good understanding of the changes that make each higher level more challenging. If you really need specifics, check out the XML file.
| Level | Settler | Chieftain | Warlord | Noble | Prince | Monarch | Emperor | Immortal | Deity |
| AI Bonus | -37.5% | -23% | -9.1% | 0 | 5% | 11% | 17.6% | 25% | 66.7% |
| AI Additional Starting Techs Bonus | None | None | None | None | None | Archery | Archery, Hunting, | Archery, Hunting, Agriculture, | Archery, Hunting, Agriculture, The Wheel, |
| AI Additional starting units | None | None | None | None |
None |
1 Def
1 Worker |
2 Def
1 Work |
3 Def
2 Work |
4 Def
2 Work 1 Settler |
| Happy / Health Bonus | 4 / 6 | 4 / 6 | 3 / 5 | 3 / 5 | 2 / 4 | 2 / 4 | 1 / 3 | 1 / 3 | 1 / 3 |
| Free Units | 24 | 18 | 12 | 8 | 6 | 4 | 3 | 2 | 1 |
| Tech Cost Factor | 70% | 80% | 90% | 100% | 110% | 115% | 120% | 125% | 130% |
| Max # of Cities Maintenance | 4 | 4 | 5 | 5 | 6 | 6 | 7 | 7 | 8 |
| # of Cities Percent Cost | 40% | 50% | 60% | 70% | 80% | 85% | 90% | 95% | 100% |
| City Distance Percent Cost | 45% | 55% | 65% | 75% | 85% | 90% | 95% | 100% | 100% |
This is the build and growth bonus given to each AI civ. The negative numbers indicate the amount reduced to make the AI slower. This means that for every 10 hammers on Settler, the AI only gets 6.25, but on Deity the AI would get 16.7. Found these percentage in Civfanatics and I am still trying to associate them to values in the help file. But Noble is supposedly the mid point, so they are at least a good reference.
These are the additional free Techs that each AI civ will start with at the beginning of the game..
These are the additional units that the AI will start the game with. This is relevant so you understand what you are against if you try an early war.
These are the starting "free" health and happiness bonus give to each city. The lower the values, the sooner you will need to consider how to make the people happy or healthy and not concentrate on building units or expanding.
This is the number of units that are "free" for your Civilization without regard to population size. Assuming you have 1 city at a population of 1 (actually just less than 4), this is the number of free units (total units, which means workers and settler also count) you would have. Each additional unit will have s cost for your civilization.
This is the factor (multiplier) that is multiplied to the base Tech Cost (for each tech) to determine the cost to the player. The AI is always multiplied for 100%. This gives the player or the AI a better chance at Tech discovery depending on the level. There are other factors that go into tech cost, but this only refers to the effect based on level.
This is the maximum value any city can have charged to it for number of cities. This becomes a factor as the number of cities increases, so does the total cost of having that many cities. This cost is spread across all the cities in your civilization. The amount of each additional city increases until the cap is reached. Example on Warlord, you total expense for number of cities will not exceed 100 gold when you have 20 cities. The actual cost would depend on map size, but on smaller maps, you would likely be charged 100 gold.
This is the percent adjusted (based on level) for the number of cities. This will make easier levels easier by reducing the cost of having a lot of cities. There are other factors that will effect this cost. This only refers to the level effect.
This is the the amount adjusted on the distance cost calculation. The base is approximately 5.5. This means that for every 5.5 squares that a city is away form the capital, that it will cost 1 gold (per 5.5 squares). On easier levels, this value will be higher. This values is also adjusted based on map size.