BoB Economy

From SotS

The contents of this page were introduced in Born of Blood.

With the release of the Born of Blood expansion came the introduction of Trade and Commerce Raiding, significantly altering the economic principles underlying the original game.

Please feel free to include your analysis of the economics of BoB here...

Note that this version of the page is for BoB 1.5.2.

Walkthrough Video


Industrial Output

Industrial Output (IO) is the lynchpin of the SotS economy. Industrial Output points are used for two things: trade and construction. The construction cost of ships measures how much Industrial Output is required to build it. So a planet with 8,000 industrial output can build up to four destroyers with a construction cost of 2,000 in one turn. IO comes from 3 sources: Population, renewable (standard) harvesting, and overharvest:

IO = ( 3*Population/1M + MIN(%INFRA, Population/100K)*Resources*0.9 + 10*OVERHARVEST ) * FACTORYBONUS
  • Every 1,000,000 people produce 3 points of IO. So you get 3000 IO on a world with 1B population.
  • With 100% Infrastructure, you'll get 0.9 IO for every point of Resources on the planet. With lower infrastructure, your IO will be proportionally lower. However, if Population/100K is less than the infrastructure, it will be used instead.
  • Every Resource point you destroy with Overharvest will yield 10 IO. This does not depend on Infrastructure, which is why Overharvest is so good on newly colonized worlds. Normally, you can Overharvest no more than 2% of the Resources on a planet every turn (less if you don't have enough population). If you have Mega–Strip Mining, you can overharvest 10%. (!!)

FACTORYBONUS is a multiplier based on technology. Without any researched tech, it is equal to 100%.

Technology Bonus
Waldo Units +15%
Cybernetic Interface +20%
Expert Systems +15%
Heavy Platforms +10%
AI Factories +50%?

These bonuses are cumulative; with all 5 technologies your industrial output is multiplied by 2.1.


Income comes from three sources: Trade, Population (taxes) and Interest:

Income = ( Population/70k + TradeOutput ) * TRADEVALUE + 1%*Savings

Any IO that is not used on construction, terraforming or infrastructure (rounded down to a multiple of 5) is converted into Trade Output (TO). If a planet with 7,500 IO spends 2,500 building a destroyer, the remaining 5,000 IO becomes TO. Every 70,000 people is taxed for 1 Trade Output. For a homeworld with 1 billion people, that's 14,285 additional TO. Trade Value (TV) represents the money that each trade point brings. This depends on three things: Economic Efficiency (game setting), AI Administration and Difficulty Level.

  • Base TV = $5.0
  • AI Administration = $7.5?

AI Admin is quite powerful. It provides a 50% bonus to all your trade income, and no other known tech in the game can increase trade income.
Hope you don't get an AI rebellion...

If you set the game to 150% Economic Efficiency, your trade value is multiplied by 150% (or whatever you set it to). In addition, if you set the AI to EASY DIFFICULTY, all human players will receive a 50% bonus to Trade Value. This multiplies with Economic Efficiency, so you could have up to 225% trade value, or $16.875 TV with AI Admin. (This may apply to Research as well but this has not yet been tested thoroughly.) Based on this info, I'd chance to guess that Hard Difficulty really just gives the AI players 150% trade and research efficiency. Hard Difficulty does not penalize human players economic efficiency.

Income from interest is separate from trade income and is equal to 1% of your savings stockpile. This is not modified by anything known.


Ship maintenance costs are as follows:

Ship class Cost/Turn
Destroyer $500
Destroyer satellite $100
Cruiser $3,000
Cruiser satellite $500
Dreadnought $15,000
Dreadnought satellite $1000

Colony maintenance costs are equal to $150 * Hazard. It doesn't matter if you've got a population of 1 person or 100 million, the planetary development cost is purely based on Hazard Rating. Nothing is known to decrease colony hazard cost. However, once you get to a certain point in the game, colony costs are really quite minimal. When you're spending $1M on ship maintainance and $2M on research, $50,000 on a hazardous world is a drop in the bucket. On the flip side, colony hazard costs can be crippling in the early–game.


Every ship/platform has a Construction Cost. Since you're giving up Trade every time you construct a ship, the true Savings Cost of ships is considerably higher than their list price. For example, a starting Tarka ER has a Savings Cost of only around $11k, but the construction cost is around 2,400. So every time you build one, you're losing 2,400 trade points — which is typically worth an additional $12k!

1 point of IO = 1 point of Construction Cost


When colonizing a brand new world, you have to build its infrastructure up to 100% to get the best use out of it.

300 points of IO = 1% Infrastructure

Each 1% infrastructure you build costs 300 IO. Every 1% Infrastructure on a 5000 Resources world generates 45 IO per turn, effectively paying for itself in 7 turns. Naturally, it takes longer for Infra on a low–Resource world to pay for itself.

There is no technology known to improve the rate of infrastructure development.

Note however that use of Infrastructure is limited by Population, where current population is under 100,000,000.


Terraforming costs a lot of IO, so you usually start terraforming after building Infra to 100%.

1,000 points of IO = (7.5 + Tech bonus) Terraforming
Technology Bonus
Atmospheric Adaptation +1.875
Terraforming Bacteria +2.625
Environmental Tailoring +2.625
Gravitational Adaptation +1.875
Elemental Nanites +3.75
Atmospheric Processors +3

With all 5 techs researched, you can more than triple the rate of terraforming to –23.25 Hazard Rating for every 1,000 IO spent.

Removing 1 hazard point costs 43–133 IO depending on tech, which is worth $215–$667 in trade if you don't have infrastructure to invest in. One hazard point costs $150/turn, so terraforming takes 1–5 turns to pay for itself. Not bad.

Colony Ships

Colony ship capacity is racial–dependent. The technology Suspended Animation (SA) increases population capacity to 5x of normal, but has no effect on terraforming/infrastructure.

DE Colonizer Human Tarka Hiver Liir Zuul
Population 50 30 100 35 250
Infrastructure 1 1 2 1.5 .55
Terraforming 0 0 0 5 0
Biome Colonizer Human Tarka Hiver Liir Zuul
Population 1,000 1,000 1,500 800 10,000
Infrastructure 5 6 4 6 2
Terraforming 20 17.5 22 30 5

When colonizing a planet, the colony fleet's population, infrastructure and terraforming are added first, then population growth and infrastructure development occurs during the end–of–turn tick. So the population you see on the first turn of a new colony will be much higher than you'd expect from these numbers.

Population Growth

(updated to 1.5.2)

Population growth in SotS is biphasic. At low populations a colony grows exponentially, increasing by a percentage every turn. However population growth is limited to a fixed value — that way a large colony cannot regenerate 500M one turn after being bombed. Bioweapon impacts cause population to decline rather than grow.

Exponential phase population growth is affected by three main factors: Race, Technology and Hazard.

The base population growth multiplier, or PGM, is determined by race:

Race PGM
Liir x1.8
Human x2
Tarka x2.1
Hiver x2.7
Zuul x3

(PGM is the number the population from last turn will be multiplied by to generate the population for this turn. For example, a PGM of x1.7 will grow a population from 1000 to 1700 in one turn.)

Certain technologies add a number to the base PGM:

Race PGM
Genetic Modification 0.1
Atmospheric Adaptation 0.06*
Environmental Tailoring 0.2
Gravitational Adaptation 0.1*
Arcologies 0.15

(*The Two Adapation technologies also increase Max_Hazard (see below) so they have a larger effect on final PGM than noted, depending on world habitability.)

These numbers are added straight to the racial PGM, so a Liir player with Genetic Modification has a total PGM of 1.9.

The Hazard rating of a planet reduces the PGM according to the following equation:

finalPGM = PGM – Hazard/Max_Hazard,

where Max_Hazard is the maximum hazard rating your race can settle.

Max_Hazard in turn depends on race and technology:

Race Racial Max Hazard
Liir 600
Human 600
Tarka 625
Hiver 650
Zuul 675
Technology Max hazard Modification
Atmospheric Adaptation plus 75
Gravitation Adaptation plus 150

So a Hiver player with both AA and GA has a Max_Hazard of 875.

Note that since you cannot settle a planet with a hazard rating greater than Max_Hazard, Hazard cannot modify PGM by more than –1. However, this does mean that Liir, with low tech and on very bad planets, can have a PGM of less than 1. This will result in their population on that planet shrinking.

The maximum population of a 0–hazard planet is equal to 100M*Size. However a highly hazardous planet will have a much lower population max until it is terraformed.

Population max is modified by Hazard Rating as follows:

Population Limit Multiplier = 1–(Hazard/(Max_Hazard+10)

For some reason, there is a slight difference between the MaxHazard used for population growth and for population limit. If a planet's Hazard is above the Max_Hazard you cannot settle it. If Hazard is increased above the Max_Hazard+10 for Population Limit, the population limit becomes 0 and the planet is glassed (everybody dies). (Confirm for 1.5.2?)

Any world of hazard rating above racial Max_Hazard +225 is permanently useless (hellworld, dustball, glassed) for your race.

Note that as a result of the numbers above it is much easier for Hivers and Zuul to grow population on high hazard worlds than the other three races.

So what is the best way to colonize?

(This formula was written for the original SOTS. Should it be removed or updated for BoB?)

This is an extremely difficult question as it depends on a lot of factors. Assuming a somewhat simplified model of the life of a colony, the following formula is an approximation of what a colony is worth:

(-150*haz)/r + 
(150*haz*(1 - r)^(-1 + (1.1111111111111112*haz)/(out*(-o + res)*ter) + 
    Log[100/(inf + o/30)]/Log[1 + 0.00003*out*(-o + res)] + 
    Log[(100000*(inf + o/30))/pop]/Log[1 + exp*(1 - haz/tol)]))/r + 
(4.5*out*(1 - r)^(-1 + (1.1111111111111112*haz)/(out*(-o + res)*ter) + 
    Log[100/(inf + o/30)]/Log[1 + 0.00003*out*(-o + res)] + 
    Log[(100000*(inf + o/30))/pop]/Log[1 + exp*(1 - haz/tol)])*(-o + res))/r + 
100000000*(1/70000 + (3*out)/200000)*
 (1 - r)^(-1 + Log[lin/(100000*exp*(inf + o/30))]/Log[1 + exp*(1 - haz/tol)] + 
   Log[(100000*(inf + o/30))/pop]/Log[1 + exp*(1 - haz/tol)])*size*
 ((1 - r)^(-exp^(-1) + (100000000*size)/lin)/r + 
  ((1 - r)^((-exp^(-1) + (100000000*size)/lin)/2)*
    (-exp^(-1) + (100000000*size)/lin))/2) + 
(83.33333333333334*haz^2*(1 - r)^(-1 + (0.5555555555555556*haz)/
     (out*(-o + res)*ter) + Log[100/(inf + o/30)]/Log[1 + 0.00003*out*(-o + res)] + 
    Log[(100000*(inf + o/30))/pop]/Log[1 + exp*(1 - haz/tol)]))/(out*(-o + res)*ter)


  • pop is the initial population of the colony (typically 50),
  • inf is the initial infrastructure of the colony (typically 1),
  • o is the amount of resources you waste overharvesting,
  • haz is the initial climate hazard,
  • size is the size of the planet (1–10),
  • res is the resources of the planet,
  • tol is your hazard tolerance (starting 600),
  • lin is your linear growth rate (starting 50000000),
  • exp is your exponential growth rate (starting 3) (note: This is not the "exp" function!),
  • out is your industry output multiplier (starting 1, 1.15 with Waldo units),
  • ter is your terraforming rate (starting 0.0075),
  • r is your return on investment (this is 0.01 if you just accumulate savings and let them gain interest, or more if you have better things to do with the money).

You may have a computation software to which you can copy–paste this formula and calculate it — otherwise you can write a small program that will implement it. Either way, you can play around with the values you can control (pop, inf and o) until you find the optimal solution (keeping in mind the colonizer cost). If the result is negative no matter what you do, you shouldn't start the colony.

As a general rule, you must bootstrap the colony's infrastructure if you don't want to suffer heavy losses (bootstrapping the population is less important, especially on low–hazard worlds). You can do this by using multiple colony ships, but I have found that it is more efficient to do this with overharvesting. The best amount can vary, but I have found that using 1 colonizer and 500 overharvest gives a good result (I haven't tried it with biomes, though).

Personal tools
SotS 2 Codex