Population growth and capacity
Population is both a colony-growth measure and an operating input for infrastructure. Growth and migration are resolved once per economy tick.
Every colony starts with 100 capacity. Completed housing and housing technologies add to that floor.
Spare housing raises the target; overcrowding lowers it. Buildings and technologies can improve the target.
Happier colonies grow faster. Habitability also matters: harsh worlds grow more slowly, while hospitable worlds give new settlements a stronger foundation. Overcrowded, unhappy colonies face stochastic decline.
Population-producing and population-consuming buildings add their per-tick totals to natural change.
Connected colonies move real population from overcrowded or unhappy worlds to happy worlds with open housing.
How the tick is calculated
max(100, 100 + housing × housing tech multiplier)capacity pressure × spare-housing bonus × happiness factor × growth tech multiplierpopulation produced × building count × growth tech multiplier − population consumedover-capacity ratio × distress × 6local growth − consumption + immigration − emigrationWhole units are guaranteed by each pressure value; its fractional remainder is the chance of one additional unit. Open housing supports natural growth, but heavy population-consuming industry can still outweigh that growth. Immigration can cover the shortfall when the colony is connected to a suitable donor world.
Keep a colony growing
- Watch the trend.The Empire tab shows each system's population change from its latest tick and warns when it is dwindling.
- Build ahead.Add housing before a mature colony reaches its cap.
- Fund the habitat.Housing and population buildings still carry resource and power requirements.
- Budget population use.Mines, refineries, shipyards, and intelligence facilities can consume population each tick.
- Connect worker colonies.A Starport lets immigration replenish a happy, mine-heavy colony from elsewhere in your empire.
- Support happiness.Happiness buildings and technologies sustain growth when a dense colony becomes crowded.
- Improve harsh worlds.Terraforming raises habitability, helping a colony's population grow and making major development proceed more smoothly.
- Protect civilian labor.Troop allocation does not remove population, but it reduces the workforce available for production.
Move people where the opportunity is
In simple terms: build a Starport on both colonies. If one colony is overcrowded or unhappy while another is happy and has free housing, people can move between them automatically each tick.
overcrowded colonies first, then unhappy colonies70%+ happiness + spare housing + route capacitycolonies losing population, then happiest and least crowded coloniesmin(origin capacity, destination capacity, available migrants, housing space)