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The fluff has always described the imperium as consisting of 1,000,000 inhabited worlds. I had always assumed this was just a saying. The imperium must consist of A LOT more worlds than one million, if it spans the majority of the galaxy. After all, it is estimated that there are over 300 BILLION stars in the galaxy. And, the Imperium isn't exactly picky about which planets they inhabit. Many appear in the fluff as containing poisonous atmosphere, inhospitable for agriculture, livestock, or virtually every other outdoor activity. Should the Imperium be described as an empire of 1 billion worlds? Anyone know of any fluff that suggests as much?

As with most things in 40k you could easily add a bunch of 0's to any numbers given by GW and things would make a lot more sense.

One Million worlds!

Number 2 "A million worlds isn't that much these days."

The fluff is pretty clear on the 1 million number. Its also part of the awesomeness of the background that there is a star spanning empire with countless people on a number of worlds that can't actually be comprehended, and yet there is still so much empty space between them that each one is effectively on its own and isolated. It's great

I tend to take "1 million worlds" as "1 million major signfcigent worlds" thats not factoring in the planets in the same system that arer inhabited, the research bases etc.

We don't actually know how many stars there are in the Milky Way, but it is usually estimated to be about 100 billion. However, you have to remember that a significant portion of these stars probably do not have planets and even more significant portion of the planets on systems which do have them are totally uninhabitable.

Still, compared to that million worlds doesn't seem much. Then again million worlds is more than any of us can comprehend, so I really would not start to increase that number. Maybe at most one could assume it means million star systems rather than million planets, so that for example whole Sol system would only count as one even though several planets are inhabited. Perhaps it is just easier to imagine that the Imperium actually covers smaller section of Milky Way than usually depicted and the Eastern Fringe is actually something like 80% of the galaxy.

In any case there would be huge swathes of uninhabited/non-imperial star systems between most imperial worlds. I'd assume that there are actually all sorts of small or even Tau scale alien empires all over the space, not to mention countless worlds filled with orks.

Also don't forget that in fantasy/scifi writing many times there are numbers that are not meant to be factual, but are more to give an impression. A million worlds might well be one of those numbers that's more "marketing" than "fact". A gross simplification that might only account for major worlds (which might actually add up to slightly less or more than a million) and which ignores smaller settlements; lost worlds; worlds fallen out of favour etc...

And that's without considering that it might also, unspoken, ignore fringe worlds on the boundaries of the Imperium - so this could just be the core worlds.

In addition the orks and other races do take up a significant chunk of the universe as well; plus its clear that the fringe areas of space are an ideal place for races like Tau to hide in.



Plus don't forget worlds lost to chaos corruption.



This number might come up again and again because many co-authored settings will likely have a cheat-sheet of facts and figures that are used as reference to help the various authors achieve a coherency between the various works.

Well compared to day another universe just to give a idea of grand 40k scale. The fedoration, one of more expansive star trek groups holds.

155 member states. So some 155 systems. Plus colonies. And inhabited planets. Even of that's 5000-10000 worlds that are main or mining and other small colonial outposts.

Compared to 40k...

1 million worlds.
Dozens, hundreds of planetary factory forgeworlds.

Its scale is vastly bigger. There's probbly 155 forgeworlds alone easily.

Yet alone all the others.

Also cant forget the whole planet busting power all of these factions have

perhapes a good chuck of them are inhabited by xenos chaos and or just bown up

"One million worlds" sounds good and it's memorable. "7 million" for instance, would just sound strange even though it's more impressive. If they wanted to go with a higher number, they'd need to go with 1 billion for the sake of simplicity. And 1 billion is probably too many, haha.

Arent we to assume as well that not all human inhabited planets are under the imperium's control? For instance, youve got some under the Tau, others that were devoured, etc etc.
Plus theres all of those that the Imperium simply never got to in the Great Crusade? Ive always been under the assumption that there were other human controlled planets outside the Imperium's sphere of influence. We certainly saw them in the HH books, and given that there were so many worlds cut off, there had to have been a good number who never made it back into the fold and exist in their own pocket.

 Jollydevil wrote:
Arent we to assume as well that not all human inhabited planets are under the imperium's control? For instance, youve got some under the Tau, others that were devoured, etc etc.
Plus theres all of those that the Imperium simply never got to in the Great Crusade? Ive always been under the assumption that there were other human controlled planets outside the Imperium's sphere of influence. We certainly saw them in the HH books, and given that there were so many worlds cut off, there had to have been a good number who never made it back into the fold and exist in their own pocket.

Yes, this is certainly true.

The imperium's "million worlds" is referred to as "a tiny fraction of the galaxy as a whole",

Whilst it covers the majority of the galaxy by dispersal (there are imperial star systems everywhere), it's nowhere near 'all the stars' and is only 'a tiny percentage of the galaxy as a whole' (an exact quote from the very first 40k rulebook, rogue trader).

A good example is the imperial sector. Sectors are stated to be a cube of space about ~ 200 light years on each side. Given the density of stars in local space to Sol, that's about 160,000 stars. We've seen many sector maps, and a few dozen (gothic sector, cadia sector, armageddon sector) to a few hundred (Calixis, Koronus, Badab) worlds in a sector is pretty normal.

locarno24 wrote:
The imperium's "million worlds" is referred to as "a tiny fraction of the galaxy as a whole",

Whilst it covers the majority of the galaxy by dispersal (there are imperial star systems everywhere), it's nowhere near 'all the stars' and is only 'a tiny percentage of the galaxy as a whole' (an exact quote from the very first 40k rulebook, rogue trader).

A good example is the imperial sector. Sectors are stated to be a cube of space about ~ 200 light years on each side. Given the density of stars in local space to Sol, that's about 160,000 stars. We've seen many sector maps, and a few dozen (gothic sector, cadia sector, armageddon sector) to a few hundred (Calixis, Koronus, Badab) worlds in a sector is pretty normal.

Its also worth mentioning that the empire isn't continuous like one would expect, or as modern land-based empires are. Its stated in the rulebook that there are vast unoccupied spaces in between some Imperial worlds, and iirc you can sometimes travel a lifetime from one (without warp travel) and still never see another Imperium inhabited planet.

We do not know how many worlds the Imperium has, and it is likely no one in-universe knows either.
The million worlds statement is metaphoric. No one in the Imperium actually knows how many worlds there are. Numbers like a thousand or a million are often used to indicate an unspecified large amount rather than as a precise number.
I guess that since we know the size of the galaxy, the size of a sector and the average number of worlds in a sector, we could calculate an approximation of the actual number of Imperial worlds.

The number of worlds in the Imperium is constantly changing - Planets are colonised, conquered or rediscovered, while others are suffer Exterminatus, are conquered by aliens, are blocked off y warp storms or are simply forgotten. A million is a round number, and sufficient to give an order or magnitude.

1,000,000 inhabited worlds.

We already know that finding an earth like planet is akin to a very smol needle in a very large haystack.

You then need to find a stable enough warp route to said planet to enable you to populate it and get things going.

And it wouldn't include all the planets in a given system.

Hmm, seems we have covered the range of views on the subject very well. They have 2 inhabited planets in our solar system alone. The Sabbat worlds, a small cluster, have hundreds on inhabited worlds on the fringe, where stars are not densely clustered. I still think the 1,000,000 is like "10,000 x 10,000," "they are legion", i.e., it sounds vast and is easy to state. I think we can safely say it isn't literal, given the imprecise nature of imperial records, planetary destruction, etc. More importantly, the galaxy just ripped in half and new empires have emerged, but the Imperium is still an empire of 1 million planets.

BrianDavion wrote:
I tend to take "1 million worlds" as "1 million major signfcigent worlds" thats not factoring in the planets in the same system that arer inhabited, the research bases etc.

This is actually not true.
Previously main rulebook actualy showed the actual number of planets by type.
How many forgeworlds, hive worlds, death worlds, etc with estimated population.

There is a thread on Dakka "how many people live in the imperium" where fluff-savant Dakkanauts provided charts and scans with pretty factual information.
The number is an estimation, but pretty close one. Still fluff states that more planets are colonised every year than Impire loses to war, rebelions or cataclysms.
So despite everythink Imperium is growing.

I rather think this is good. An much more realistic.

Imperium of Man CONSIDERS the galaxy as a whole to be it's rightful domain, but in fact the humanity is so scarcely spread across the galactic disk, it is more of a wishful thinking.

What is more curious is that apart from Imperium and Orks, only Hruds hold enough galactic space to be even visible on the galactic map.

 jhe90 wrote:
Well compared to day another universe just to give a idea of grand 40k scale. The fedoration, one of more expansive star trek groups holds.

155 member states. So some 155 systems. Plus colonies. And inhabited planets. Even of that's 5000-10000 worlds that are main or mining and other small colonial outposts.

Compared to 40k...

1 million worlds.
Dozens, hundreds of planetary factory forgeworlds.

Its scale is vastly bigger. There's probbly 155 forgeworlds alone easily.

Yet alone all the others.

The federation only covers a small part of two Quadrants ot the milky way, though. The federation is probably comparable in expansion to a single Necron dynasty, so much larger than the Tau but on a Galactic scale still quite irrelevant.
When talking about the Imperium having only 1Million worlds I like to bring up that map as well:


It's as easy as that: In between countless ork-worlds there are some worlds colonized by humans .
I imagine that's how the Dark Age of technology and the Eldar empire could exist at the same time: vast areas of space were inhabited by the Eldar (or Orks), but in between there were also humans here and there.

Sgt. Cortez wrote:

 jhe90 wrote:
Well compared to day another universe just to give a idea of grand 40k scale. The fedoration, one of more expansive star trek groups holds.

155 member states. So some 155 systems. Plus colonies. And inhabited planets. Even of that's 5000-10000 worlds that are main or mining and other small colonial outposts.

Compared to 40k...

1 million worlds.
Dozens, hundreds of planetary factory forgeworlds.

Its scale is vastly bigger. There's probbly 155 forgeworlds alone easily.

Yet alone all the others.

The federation only covers a small part of two Quadrants ot the milky way, though. The federation is probably comparable in expansion to a single Necron dynasty, so much larger than the Tau but on a Galactic scale still quite irrelevant.
When talking about the Imperium having only 1Million worlds I like to bring up that map as well:


It's as easy as that: In between countless ork-worlds there are some worlds colonized by humans .
I imagine that's how the Dark Age of technology and the Eldar empire could exist at the same time: vast areas of space were inhabited by the Eldar (or Orks), but in between there were also humans here and there.

Yeah. That all makes sense.

Scale wise 40k Is insane vs the other Sci fi. They try to be reasonable.. 40k dials up to 11 and then dials 11 to 11

The only star empire equal in scale may be the star wars empire at height, or the borg controlled space.

One million worlds is massive. Even if only a fraction populated heavily. The Impirum has trillions upon trillions of subjects. It's so vast it cannot map itself.

Its so vast a change in security coding can take decades to prepare and exacute.

I think you'll find Starwars is actually bigger with a LOT more lore written about it. The difference is that its not a war-torn grim-dark setting (if anything its almost the polar opposite even though it still has wars and Sith).

As for going to 11 and then 11 again I'd argue that Dune has to get in there somewhere too for going utterly insane.

I'd always assumed about half a billion in my own head, and added many 0s to all other numbers, like the number of marines in SM chapters.

 Overread wrote:
I think you'll find Starwars is actually bigger with a LOT more lore written about it. The difference is that its not a war-torn grim-dark setting (if anything its almost the polar opposite even though it still has wars and Sith).

As for going to 11 and then 11 again I'd argue that Dune has to get in there somewhere too for going utterly insane.

OK I may agree on scale changes if expanded universe kicks in. A vast area of star wars is unclaimed and un mentioned in films but it seems empire was big on expanding into outer rim and unknown wn space.

The area it involves is vast, and yeah. They have great FTL so that helps expansion.

I'm not sure it's not so war torn. If you take the time line from say first, the origins of Anakin and clone wars to the latest forst order. There had been 2-3 rebellions, multiple major intergalactic wars, several planet destroying super weapons.

Losses of billions of lives?

Now add up before. The constant sith Jedi ward that lasted for on and off melenia. With luke maybe being present. There's maybe been in 2-3 generations, 3-4 galaxy spanning wars and rebellions equal to "world wars"

After that the vy zong invasion that killed many many more. Like entire planets. Corusant occupied and conquered.

Star wars is a pretty darn tough universe to live in.

40k takes the grin cake but od day we can draw a few similarity. Sure life is better yes. But thr fact is its no cake walk.

True. Dune has its moments, and star trek just well... When earth about to be attacked by Suprise borg fleet they round up about 20 starship. And not all heavy galaxy class at that.

Lol. One 40k cruiser squadron out weighs. So we can say they are safely the minnow of the comparison. So let's leave that one to play in the corner of galaxy out of the way.

Ok, I decided to calculate the approximate number of worlds in the Imperium.

So we have a few sectors that have been comprehensively detailed, such as the Gothic Sector and the Calixis Sector, both of which have something over a 100 Imperium-controlled planets. Now there will probably be sectors with more or less planets, so just to make things simple I will take 100 Imperium-controlled planets as the average in a sector.
-Sectors are a grid on the galactic map. Each is a block of space 200 light years across. Space is 3-dimensional, and 200 x 200 x 200 is 8000000. That would be the volume of a sector in cubic light years.
-The Imperium spreads across the galaxy almost from edge to edge ( it hasn't reached the extreme edges).
-According to Wikipedia, the volume of a galaxy like the Milky Way is estimated to be approximately 8000000000000 cubic light years ( 8×10 to the power of 12)
-So... If we divide that number by 8000000, we get 1000000 sectors in the galaxy.
-Multiplying the number of sectors by 100 gets us to a grand total of 100000000 Imperium-controlled worlds in the galaxy.

Obviously, this is only a very rough estimate that does not take in account many factors, but it does show that the Imperium controls quite a bit more than a million worlds and is quite huge, as befits a galaxy-spanning empire.


Edit: fixed a conversion error that produced a rather stunningly large outcome

Sorry Iron Captain, but the 10^60 is cubic METRES, not cubic light years. The galaxy is approximately 8x10^12 cubic light years, so there are about a million sectors or 100 million planets by your calculation.

As a sense check, your original calculation has each star in the galaxy with 10^40 planets. I think we'd notice...

It comes down to sector density - are those average? Vast areas of the galaxy are simply uninhabitable. Suns at the core of the galaxy will be so tightly packed (all less than 1 LY apart) that they'll be fried by each others' solar radiation, Gas clouds or stellar nurseries will not have formed planets.

 Iron_Captain wrote:
That, or I made a silly error in my calculation somewhere. Maybe someone could check it? I never trust my own calculations

Considering that your calculations give us about 4 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 times more imperial worlds than there are stars in the galaxy, I'd have to guess your math might be slightly off...


Automatically Appended Next Post:

 Momotaro wrote:
Sorry Iron Captain, but the 10^60 is cubic METRES, not cubic light years. The galaxy is approximately 8x10^12 cubic light years, so there are about a million sectors or 100 million planets by your calculation.

As a sense check, your original calculation has each star in the galaxy with 10^40 planets. I think we'd notice...

It comes down to sector density - are those average? Vast areas of the galaxy are simply uninhabitable. Suns at the core of the galaxy will be so tightly packed (all less than 1 LY apart) that they'll be fried by each others' solar radiation, Gas clouds or stellar nurseries will not have formed planets.

I think the maps of sectors we've seen are usually on somewhat important areas, and may contain more inhabited worlds than on average. And I really don't think that we should assume that there even are any sectors everywhere, there are probably huge swathes of nothing between many of them.

A million worlds is actually just fine.

Remember that while the Imperium is the largest single entity in the galaxy, they do NOT occupy a majority of the galaxy. They only occupy a tiny fraction of the total physical space in the galaxy due to the intricacies of warp travel not being linear. Not every physical location can be accessed by warp in the first place, and others are very very difficult to access.

The fluff is quite clear that there is a huge amount of Locus Incognita, unknown space, in between everything. There could be entire empires hidden among the stars that have never had contact with any of the major players in the galaxy.

And while there are trillions upon trillions of stars in the galaxy, only a small portion of those might have planets. And of those planets, only a smaller portion will have anything of value(livable environment, mineral resources, etc...).

A million inhabited worlds is actually quite a lot. And of course this number doesn't include any space stations or other outposts that really wouldn't qualify to be an "Inhabited World". You'll still end up with an insane Imperial population.

Hive Worlds alone give massive population numbers. According to Lexicanum there are approximately 32,380 Hive Worlds. If we take the average of the known populations of 19 listed hive worlds(Lexicanum lists the populations for 19 hive worlds) to be representative of the average across the Imperium, we get an average of ~55 billion people per Hive World.

Multiply that by 32,380 Hive Worlds and you get 1,780,900,000,000,000,000 people. That's 1 Quintillion, 780 quadrillion, and 900 trillion humans on Hive worlds alone.

 Momotaro wrote:
Sorry Iron Captain, but the 10^60 is cubic METRES, not cubic light years. The galaxy is approximately 8x10^12 cubic light years, so there are about a million sectors or 100 million planets by your calculation.

As a sense check, your original calculation has each star in the galaxy with 10^40 planets. I think we'd notice...

It comes down to sector density - are those average? Vast areas of the galaxy are simply uninhabitable. Suns at the core of the galaxy will be so tightly packed (all less than 1 LY apart) that they'll be fried by each others' solar radiation, Gas clouds or stellar nurseries will not have formed planets.

Ah, Praise the Emperor. I already was shocked at how crazily huge that number was. I already thought there might be a conversion error somewhere. Funny how I never notice those things myself.
The 100 planets per sector is an average yes, based on some of the sectors that have been detailed in the fluff. The actual number of planets is going to be different, because as you say not every part of the galaxy is suitable for habitable planets, and one could also imagine the sectors nearest to Terra to have far more than 100 colonised planets. But that would make the calculation more complicated than I care for. Maybe someone who really enjoys math and astronomy would like to make a better model.

Considering that the Imperium has no clue how many space marine chapters have been created I think it’s safe to say that 1m worlds is an entirely fictitious number.

The Imperium has no clue how many worlds are out there. Might be 1m, might be 100m.