How Does Population Growth Work?

[CivilizedPlayer]

I have over 170 hours logged on Civ 5 (which may not be much compared to some of the more hardcore, but it certainly feels like a lot to me), and it just occurred to me: I have no real idea how population growth works.

I understand that it takes 2 food to feed 1 citizen (usually, not including SP's and whatever else), but beyond that I'm kind of clueless. So although I would appreciate any tips, my main questions are:

1) What determines how quickly my next citizen will be born. ie: When that little bar says "6 more turns until new citizen", what determines that it will be 6 more turns?

2) What are the effects of aqueducts on pop growth? It says it stores 40% of food, but what does that actually mean? Will I get a new citizen in only 60% of the time it should take?

3) Is their any benefit to having massive food surpluses? I currently something like 30 extra food in each of my (very large) 2 cities. On the other hand, the AI has something like 3 extra food. Is their any benefit to my massive surpluses? What is the ideal amount of extra food to have?

 

[FeiLing]

The larger a city, the more food needs to be accumulated for it to grow even larger (no formulas from me; mouseover the food stuff in a city and see how large the needed amount is and how much you already have). Therefore a large surplus per turn makes you grow faster and is never bad. Of course there are a lot of social policies or wonders, that give percentage bonuses to growth, for e.g. +10% growth. This will make a city that has a 30 food surplus per turn produce 33 food per turn (actually I'm not sure if that bonus comes before or after the amount your current pop eats (2 per pop) is taken away). An aquaduct is actually super imba as it will gift you an already 40% filled food pool every time a city has grown. For e.g. when you city is at 88/90 with +4 food per turn, without an aquaduct you'd grow and be at 2/100. With an aquaduct you'd also grow, but already be at 42/100. If the new citizen works a 2-food tile which means you'd still have a surplus of +4 per turn, then that effectively reduces the time for the next growth by 10 turns from 25 to 15.

 

[Thander]

Food surpluses help grow the city faster, but it can become useless if you hit your happiness cap. If you can't support more population, the citizens working on food are worthless. Switch them to other things like production or gold. Over the course of the game you will hit various happiness caps based on when you gain access to new luxury resources, get new social policies, and build happiness buildings (and a few other things).

Also if the city runs out of tiles to work (bad location, low culture), the extra citizens and surplus food won't help much. Unless you have specialist slots to fill, it might be best to move citizens around to lower growth. You can also try replacing improvements with non-food ones if you have way too much growth. That can usually be avoided if you plan ahead how much food improvements to make.

 

[JakeIL7]

Growth is pretty simple: Any excess is added to your food surplus. When your surplus gets big enough, it is removed and you get a new citizen. Here is the rub: if you consume more food than you make, the extra required will be taken from your food stores. If your stores hit 0 and you still cannot feed the population, it decreases by 1 pop until your food produced is greater than or equal to the food consumed.

By default, each citizen eats 2 food per turn.

Because of this mechanic, aqueducts have 2 uses. First, as mentioned before, growth may be higher if you continue to have the same food surplus before. Basically, they make it quicker to hit the next goal. However, they also guard against population decrease due to things like enemies in your fields and such. This is because when you grow, you don't loose all your food. Just 60%.

 

[vitalstatistixd]

Food surpluses help grow the city faster, but it can become useless if you hit your happiness cap. If you can't support more population, the citizens working on food are worthless. Switch them to other things like production or gold. Over the course of the game you will hit various happiness caps based on when you gain access to new luxury resources, get new social policies, and build happiness buildings (and a few other things).

Also if the city runs out of tiles to work (bad location, low culture), the extra citizens and surplus food won't help much. Unless you have specialist slots to fill, it might be best to move citizens around to lower growth. You can also try replacing improvements with non-food ones if you have way too much growth. That can usually be avoided if you plan ahead how much food improvements to make.

I'm trying to understand city management as well, so could someone explain why sometimes it's not efficient to allocate people to work the tiles? Are specialists always better? Do specialists generate zero unhappiness?

 

[FeiLing]

Every specialist causes 1 unhappiness, just like a normal citizen. Unless you got the Democracy (Freedom) SP, which halves that for Specialists. Note that an unemployed citizen actually produces 1 hammer and counts as a specialist. Therefore he produces 2 hammers with the Statue of Liberty (and +1 gold with commerce finished and also science when you are Korea or have Secularism (Rationalism)) and causes only 0.5 unhappiness with democracy, which is why it can very well be worth to not work a tile.

 

[Brigg]

One note, food is calculated first, then growth. You can get a free production with careful management.