SotS Economy

From SotS

MATHCRAFT: It's the Economy, Stupid. An in-depth analysis of industry, trade, terraforming and colonization in Sword of the Stars.

NOTE: The information in this article is based on observations of the original retail version of the game. Statisitics and measurements have changed in the subsequent updates but the general formulas and conclusions are relevant.

Originally posted by PiousFlea

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 = ( Population/500k + %INFRA*Resources + 10*OVERHARVEST ) * FACTORYBONUS
  • Every 500,000 people produce one point of IO. So you get 200 IO on a size–1 world, up to 2000 for a size–10 world.
  • With 100% Infrastructure, you'll get 1 IO for every point of Resources on the planet. With lower infrastructure, your IO will be proportionally lower.
  • 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. 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 +20%

These bonuses are cumulative; with all 5 technologies your industrial output is multiplied by 180%.


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 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 = $6.0

AI Admin is quite powerful. It provides a 20% 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 $13.5 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 $5,000
Cruiser satellite $500
Dreadnought $20,000
Dreadnought satellite $1000

Colony maintenance costs are equal to $119 * 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 worth $18k!

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.

1,000 points of IO = 3% Infrastructure

Each 1% infrastructure you build costs 333 IO. Every 1% Infrastructure on a 5000 Resources world generates 50 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.


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

1,000 points of IO = (6.6 + Tech bonus) Terraforming
Technology Bonus
Terraforming Bacteria +1.2
Atmospheric Processors +1.5
Elemental Nanites +3.3

With all 3 techs researched, you can nearly double the rate of terraforming to –12.6 Hazard Rating for every 1,000 IO spent.

Removing 1 hazard point costs 79–152 IO depending on tech, which is worth $593–$1140 in trade. One hazard point costs $119/turn, so terraforming takes 6–10 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
Population 50 30 100 35
Infrastructure 1 1 2 1
Biome Colonizer Human Tarka Hiver Liir
Population 1000 1000 1500 800
Infrastructure 5 6 4 5
Terraforming 20 18 22 30

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

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.

The following numbers are true for Human, Tarka and Liir population on a zero–hazard planet. Note that the population growth technologies are strictly linear, you cannot get Gravitational Adaptation without having all 3 of the earlier population techs. Hivers have +50% population growth at all times but their max populations are the same.

Tech level Pop Growth Up to Improvement
No research Pop increases by 275% Up to +50M/turn
Gene Modification Pop increases by 303% Up to +55M/turn (+10%/+10%)
Atmospheric Adaptation Pop increases by 348% Up to +58M/turn (+26%/+16%)
Environmental Tailoring Pop increases by +408% Up to +68M/turn (+48%/+36%)
Gravitational Adaptation Pop increases by +511% Up to +73M/turn (+86%/+46%)

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 growth and population max is modified by Hazard Rating as follows:

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

MaxHazard is the highest hazard rating barely survivable by your race and can be increased by research. Colonists at a MaxHazard planet would have a 0% growth rate, so you are unable to colonize there. At 50% of MaxHazard (275 for starting tech), your colony will grow at half the normal rate and cap out at half of the normal population. 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 increased above the MaxHazard for Population Growth, your population will stop growing. If Hazard is increased above the MaxHazard for Population Limit, the population limit becomes 0 and the planet is glassed (everybody dies).

Technology MaxHazard (Growth) MaxHazard (Limit)
No research 550 560
Atmospheric Adaptation 600 610
Environmental Tailoring 650 660
Gravitational Adaptation 700 710

Any world of hazard rating 700 or above is permanently useless (hellworld, dustball, glassed) for your race.

Although Hivers are supposed to be resistant to hostile environments, in all of my testing I have not found any racial differences in the Hazard formulae. However, because they have superior basic colonizers and growth rate, settling a 300+ hazard world is not as big of an economic blow for Hiver as for other races.

So what's the most cost effective way to colonize?

I made a spreadsheet to calculate this out. Note that the costs/makes money means how much money the colony generates – it does NOT include the cost of the colonizer ships!!

With a Human player and no researched technologies (starting game),

Size 5, 5000 resources, 0 hazard Max pop in Max infra in Max terra in Net Profit
1 basic DE colonizer 20 turns 25 turns N/A $428,436 over 25 turns
1 Suspended Animation DE 19 turns 25 turns N/A $497,802 over 25 turns
5 basic DE colonizers 19 turns 20 turns N/A $641,289 over 25 turns
5 Suspended Animation DEs 19 turns 19 turns N/A $701,332 over 25 turns
Size 5, 5000 resources, 300 hazard Max pop in Max infra in Max terra in Net Profit
1 basic DE colonizer 39 turns 31 turns 38 turns –$712,846 over 39 turns
1 Suspended Animation DE 38 turns 30 turns 37 turns –$613,537 over 39 turns
5 basic DE colonizers 29 turns 21 turns 28 turns $182,686 over 39 turns
5 Suspended Animation DEs 29 turns 21 turns 28 turns $241,118 over 39 turns
20 basic DE colonizers 22 turns 12 turns 19 turns $773,816 over 39 turns
20 Suspended Animation DEs 21 turns 12 turns 19 turns $954,623 over 39 turns

Conclusion: Colonizing a 300 hazard world is EXPENSIVE! Never colonize with a single colonizer. Going from 1 colonizer to 5 colonizers, you'll save nearly $200k per colonizer. Going from 5 to 20, you still save $47,567 per colonizer. If you really want to get colonies going, stack the colonizers 20 at a time.

With tech up to Expert Systems / Biome Colonizer / Atmospheric Adaptation:

Size 5, 5000 resources, 400 hazard Max pop in Max infra in Max terra in Net Profit
1 basic DE colonizer 31 turns 23 turns 29 turns –$858,712 over 31 turns
1 Suspended Animation DE 31 turns 23 turns 29 turns –$777,110 over 31 turns
5 basic DE colonizers 26 turns 15 turns 22 turns –$6,280 over 31 turns
5 Suspended Animation DEs 25 turns 15 turns 22 turns $44,532 over 31 turns
1 Biome Colonizer 24 turns 15 turns 21 turns $138,536 over 31 turns
20 Suspended Animation DEs 20 turns 8 turns 15 turns $807,526 over 31 turns
4 Biome Colonizers 19 turns 8 turns 13 turns $1,133,288 over 31 turns

Conclusion: Biome colonizers own. While massive fleets of DE colonizers are cheaper and will get your infrastructure going faster, the terraforming bonus of Biomes means that your colonies don't bleed huge sums of money while you get them up to speed. Always use Biomes if they are available. Going from 1 Biome to 4 Biomes saves you over $300k per biome. So use as many biome colonizers as you can when going for hazardous worlds!!

How good is terraforming tech? Taking the previous 400 hazard world with one Biome colonizer:

Size 5, 5000 resources, 400 hazard Max pop in Max infra in Max terra in Net Profit
no Terraforming tech: 24 turns 15 turns 21 turns $138,536 over 31 turns
Terraforming Bacteria 24 turns 15 turns 20 turns $215,284 over 31 turns
Atmospheric Processors 24 turns 15 turns 19 turns $284,904 over 31 turns
Elemental Nanites 23 turns 15 turns 18 turns $380,383 over 31 turns

Conclusion: Terraforming technology definitely saves you money when settling hostile worlds. However, it's not really that much money – from +$77k for Bacteria up to +$242k for Nanites. And just how often do you settle a 400 hazard world? If you are at war with a race who's home climate just so happens to be 550 Hazard for your race, then Terraforming tech is the way to go. Otherwise you might think about passing on these.

How about overharvesting a planet to get it up to speed? Let's take the same colony and use overharvest. The first case uses standard Overharvest (2%) for 5 turns, the second case uses Mega-Strip Mining (10%) for 1 turn:

Size 5, 5000 resources, 400 hazard Max pop in Max infra in Max terra in Net Profit Resources destroyed/left
no Overharvest 24 turns 15 turns 21 turns $138,536 over 31 turns 0 destroyed, 5000 left
2% Overharvest first 5 turns 22 turns 10 turns 17 turns $530,131 over 31 turns 480 destroyed, 4520 left
10% Overharvest on first turn 21 turns 9 turns 16 turns $650,580 over 31 turns 500 destroyed, 4500 left

Oh my! Overharvesting is quite effective. But just how long does it take for you to feel the loss of those resources?

Colony Resources Industrial Output Income (100% Trade) Time to unprofitability
No overharvest 5000 9,000 $80,714 N/A
2%x5 overharvest 4520 8,279 $77,111 140 turns
10% overharvest 4500 8,250 $76,964 168 turns
Unless your game is going to last more than 140 turns, overharvesting has practically no downside. It takes 140 turns before the loss of resources from standard overharvest becomes unprofitable, and Mega-Strip Mining is even better! (just don't forget to turn it off after one turn)

Conclusion: If a colony has high hazard, is near the front lines, or both, OVERHARVEST!! If you plan on winning within 140 turns, OVERHARVEST! There's no sense in waiting 21 turns for a colony to become productive when you could do it in 16–17 turns with overharvest.

PLEASE NOTE THAT: waiting for 20 colonizers is not a good idea unless a planet is really hazardous! For every turn you wait to colonize a planet, you lose one turn's worth of long-term income (which is >$70,000 for most planets) and also give your opponent one more turn to get to your planet and destroy it before it's fully built and defended. The only planets that you'd want to wait until you have a large number of colonizers (~20 standard or ~4 biome) are high–hazard worlds, 300 and above. And that's only because putting 30 people on a 350 hazard world and paying $40,000 per turn for next–to–zero industrial output doesn't make any sense.

  • Note: Remember that colonizers also provide initial infrastructure points. It is wise to continually send waves of colonizers at newly colonized planets. This will rapidly allow you to build up your infrastructure, which will in turn allow you to rapidly terraform the planet. Even high hazard worlds can be quickly brought down to 0 Hazard rating if you continue to supply mass colonizers. Once a colony is producing ~8 infrastructure per turn, it will finish up quickly enough on its own and no longer needs drastic support.

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