By Zombie

Most of the tabes listed on this page can be downloaded here. (18kb Excel Worksheet).

Core Stats | Skill Level Stats | Calculating Stats from the Core | Strange and Interesting Facts | A Word About The OSG
What the Mind Probe and Psi-Amp Don't Tell You | Editing Alien Stats | Additional Stats | Acknowledgments

From the surface, alien stats seem like a straight-forward idea. As most of us know, there are 5 skill levels to the game and as the difficulty increases, so do enemy stats. Why then do most stat listings around the net only cover one? Even worse, the guides which show all skill levels have values which are unsubstantiated and/or just pull the OSG's (Official Strategy Guide, by David Ellis) numbers at face value. Perhaps it is just easier to blindly copy information than it is to verify.

In any event, the X-COM community deserves better. For this reason, I set out on a long journey to gather all the stats at each skill level one summer day. Six months and countless hours later, I had the data. Unfortunately, this was only for the Collector's Edition of the game. What about the other versions though? Collecting stats from them would be possible, just not practical. There had to be a better (and faster) way.

Core Stats

Thanks to some research by a few forum members, it was determined that alien stats reside in the executable. Not only that, but there is only one set of numbers, not five.  This had a couple of important implications:

• Comparing stats between versions was now possible and easy.
• Because there is only one set of alien stats, it must mean that a skill level stat is calculated directly off this "core" or base group.

After checking the executables of as many game versions as possible, all the alien stats matched. Therefore, any information presented here will apply to your version of the game! Here then, are the base values:

Core alien statistics

Alien Race/Rank	TU	Sta	He	Br	Rea	FA	TA	Str	PST	PSK	Fr	L/R	Re	Un	EnR	VPS	Agg	Mel	Int
Floater Soldier	50	90	35	80	50	50	58	40	35	0	8	6	4	12	30	12	2	70	4
Floater Navigator	50	90	35	80	50	50	58	40	35	0	8	6	4	12	30	14	2	70	5
Floater Medic	50	90	35	80	50	50	58	40	35	0	8	6	4	12	30	16	1	70	6
Floater Engineer	50	90	35	80	50	50	58	40	35	0	8	6	4	12	30	18	2	70	7
Floater Leader	55	95	40	80	60	60	58	47	40	0	16	12	8	12	30	25	0	70	8
Floater Commander	60	100	45	80	66	63	65	48	45	0	24	18	12	16	30	35	0	76	8
Sectoid Soldier	54	90	30	80	63	52	58	30	40	0	4	3	2	2	30	10	2	76	3
Sectoid Navigator	54	90	30	80	63	52	58	30	40	0	4	3	2	2	30	12	2	76	4
Sectoid Medic	54	90	30	80	63	52	58	30	40	0	4	3	2	2	30	14	1	76	5
Sectoid Engineer	54	90	30	80	63	52	58	30	40	0	4	3	2	2	30	16	2	76	6
Sectoid Leader	54	90	30	80	63	52	58	30	50	50	4	3	2	2	30	20	1	76	7
Sectoid Commander	54	90	30	80	63	52	58	30	50	60	4	3	2	2	30	25	0	76	8
Snakeman Soldier	40	80	45	80	45	58	65	47	40	0	20	18	16	12	30	15	2	54	2
Snakeman Navigator	40	80	45	80	45	58	65	47	40	0	20	18	16	12	30	17	2	54	3
Snakeman Engineer	40	80	45	80	45	58	65	47	40	0	20	18	16	12	30	20	2	54	4
Snakeman Leader	40	80	45	80	55	65	65	47	45	0	20	24	22	20	30	28	2	54	5
Snakeman Commander	45	84	55	80	65	58	65	47	50	0	26	26	22	20	30	36	2	54	6
Ethereal Soldier	68	96	55	80	75	74	80	48	50	40	35	35	35	35	40	20	1	85	6
Ethereal Leader	68	96	55	80	75	74	80	48	60	45	40	40	40	40	40	30	1	85	7
Ethereal Commander	68	96	55	80	75	74	80	48	65	50	45	45	45	45	40	40	1	85	8
Muton Soldier	56	90	125	80	60	54	62	70	25	0	20	20	20	10	40	15	2	78	2
Muton Navigator	56	90	125	80	60	54	62	70	25	0	24	24	24	15	40	17	2	78	3
Muton Engineer	56	90	125	80	60	54	62	70	25	0	28	28	28	20	40	19	2	78	4
Reaper	62	90	148	90	64	0	0	90	35	0	28	28	28	4	34	25	2	80	2
Chryssalid	110	140	96	100	70	0	0	110	50	0	34	34	34	34	40	25	2	80	4
Silacoid	40	80	114	100	40	0	0	70	80	0	50	50	50	10	40	20	2	80	3
Celatid	70	90	68	90	40	100	0	70	60	0	20	20	20	20	40	20	2	80	4
Sectopod	62	90	96	110	64	60	0	90	100	0	145	130	100	90	50	30	1	80	4
Cyberdisc	62	90	120	110	64	60	0	90	100	0	34	34	34	34	50	20	1	80	5

Skill Level Stats

Below you will find the stats to each skill level. Click on a tab to expand the selection.






From the tables above it quickly became apparent that some stats change while others do not. The ones which never change are:

• Health
• Bravery
• Throwing Accuracy
• Energy Recharge
• Victory Points
• Aggression
• Intelligence
• Most other stats

The stats which do change are:

• Time Units
• Stamina/Energy
• Reactions
• Strength
• Psionic Strength
• Psionic Skill
• Melee
• Firing Accuracy
• Armor

Calculating Skill Level Stats from the Core

"How exactly are the changing stats calculated?" That was the big question on my mind while looking at the data. First I compared Beginner against Experienced. A ratio between the two stat levels yielded a rough percentage, but in order to nail it down exactly a comparison between all the skill levels was necessary. What I came up with was rather surprising; most stats increase with a constant percentage while a couple stats are strange. The stats which change by constant percentage include:

• Time Units: 4%
• Stamina/Energy: 4%
• Reactions: 6%
• Strength: 2%
• Psionic Strength: 4%
• Psionic Skill: 4%
• Melee: 4%

Those which are different include:

• Firing Accuracy: Beginner level FA is one-half the core value, while Experienced through Superhuman recieve a 6% increase per level.
• Armor: Beginner level aliens have one-half the core value while higher difficulty levels stay at the core with no improvement per level.

To arrive at an equation linking the core to the different skill levels required a little creative thinking on my part. Since the Beginner skill level numbers match the core group exactly, no modification is necessary. For this reason, I assumed the modifier would be 0 for the lowest skill level and something simple (think: integer) for the higher levels. Turns out, this was a valid theory which led me to introduce a new term in the equation to bridge skill levels called the Skill Level Multiplier, or SLM for short.

       SLM values

• Beginner: 0
• Experienced: 1
• Veteran: 2
• Genius: 3
• Superhuman: 4

With this last piece of data in-hand I was able to formulate a generalized equation to describe the stats which change and have Beginner levels equal to the core.

Skill Value = INT(Core Value * (100 + (Percentage * SLM)) / 100)

As an example, let's assume we want to find the number of Time Units a Superhuman Chryssalid has. The core TU for the Chryssalid is 110 while the percentage is 4% and the Skill Level Multiplier is 4. Now it is just a matter of substituting these values into the equation:

Superhuman TU = INT(110 * (100 + (4 * 4)) / 100)
                        = INT(110 * (100 + 16) / 100)
                        = INT(110 * 116 / 100)
                        = INT(12760 / 100)
                        = INT(127.60)
                        = 127

This number agrees with the Chryssalid's TU during an actual Superhuman mission. (Note: The "INT" function is a necessary part of the equation because it models how the game handles numbers with decimals. Since X-COM was programmed using declared variables as Integer to save space, the INT function serves as the liaison between a real-world calculation and a number given in the game. Therefore, fractional parts of the number are dropped or truncated).

Strange and Interesting Facts

• Zombie stats are not listed in the executable where the normal aliens are situated. Not only that, but their stats do not change as the skill level increases. For more information on this oddity, see the Editing Alien Stats heading on this page.
• Civilian stats are also constants and do not change.
• Chryssalids which are spawned in a mission by the game have stats modified in the normal way. However, Chryssalids which hatch from Zombies have all their stats set to their core, irregardless of current difficulty level. For instance, a normal Superhuman Chryssalid has 127 TU while a Superhuman Chryssalid hatched from a Zombie has only 110 TU! Apparently the game neglects to modify the stats during a mission.

A Word About The Official Strategy Guide

Alien Stats (Characterestics) start on pg 249 and continue to pg 260. The Beginner Skill level is fine except for a few small errors. However, at the higher difficulty levels the OSG's data falls far short of expectations. I have a suspicion the author failed to recognize what effect integer rounding would play or wasn't privy to the exact equation. In any event, be aware that the OSG's alien stat tables should not be used due to massive errors. The information presented here supersedes that from the OSG through rigorous tests.

What the Mind Probe and Psi-Amp Don't Tell You

Often, during the heat of a battle, you may decide to use the Mind Probe or Psi-Amp to look at an alien's stats. These devices really only touch the tip of the iceberg in terms of what is possible to know. And although Soldier and Tank attributes can be accessed directly, they have the same limitations placed on them as the aliens. This is due to the fact that only so much information can be presented on one screen.

Below is a table of the data which isn't normally shown. Note: For stats which change due to skill level such as Melee and Psi, the core values are given. Also, psionic stats will only be shown in-game when Psionic Skill is > 0. Most units have no skill in this area and thus have missing stats.

Unseen stats

Alien Race/Rank	Mel	EnR	St	Kn	Flt	Dmf	PSk	Pst	Msb	VPS	Agg	Int
Floater Soldier	70	30	21	16	2	1	0	35	4	12	2	4
Floater Navigator	70	30	21	16	2	1	0	35	4	14	2	5
Floater Medic	70	30	21	16	2	1	0	35	4	16	1	6
Floater Engineer	70	30	21	16	2	1	0	35	4	18	2	7
Floater Leader	70	30	21	16	2	1	0	40	4	25	0	9
Floater Commander	76	30	21	16	2	1	0	45	4	35	0	8
Sectoid Soldier	76	30	16	12	0	1	0	40	3	10	2	3
Sectoid Navigator	76	30	16	12	0	1	0	40	3	12	2	4
Sectoid Medic	76	30	16	12	0	1	0	40	3	14	1	5
Sectoid Engineer	76	30	16	12	0	1	0	40	3	16	2	6
Sectoid Leader	76	30	16	12	0	1	50	50	3	20	1	7
Sectoid Commander	76	30	16	12	0	1	60	50	3	25	0	8
Snakeman Soldier	54	30	18	18	0	5	0	40	4	15	2	2
Snakeman Navigator	54	30	18	18	0	5	0	40	4	17	2	3
Snakeman Engineer	54	30	18	18	0	5	0	40	4	20	2	4
Snakeman Leader	54	30	18	18	0	5	0	45	4	28	2	5
Snakeman Commander	54	30	18	18	0	5	0	50	4	36	2	6
Ethereal Soldier	85	40	20	15	0	6	40	50	4	20	1	6
Ethereal Leader	85	40	20	15	0	6	45	60	4	30	1	7
Ethereal Commander	85	40	20	15	0	6	50	65	4	40	1	8
Muton Soldier	78	40	21	16	0	7	0	25	4	15	2	2
Muton Navigator	78	40	21	16	0	7	0	25	4	17	2	3
Muton Engineer	78	40	21	16	0	7	0	25	4	19	2	4
Reaper	80	34	23	16	0	10	0	35	4	25	2	2
Chryssalid	80	40	21	16	0	9	0	50	4	25	2	4
Silacoid	80	40	10	10	0	8	0	80	4	20	2	3
Celatid	80	40	12	12	6	1	0	60	4	20	2	4
Sectopod	80	50	23	16	0	11	0	100	4	30	1	4
Cyberdisc	80	50	15	15	2	12	0	100	4	20	1	5
Zombie	80	20	18	18	0	13	0	80	4	18	2	3
Civilian	50	20	21	16	2	1	0	5	4	10	0	1
Tank	70	50	16	16	0	4	0	100	30	20	2	3
Hovertank	70	50	12	12	6	4	0	100	30	20	2	3

Melee (Mel): All units have this ability but only the Reaper, Chryssalid, Silacoid and Zombie can use it. The melee value is a percentage used to calculate the base chance of "hitting" the target.
Energy Recharge (EnR): Determines how fast a unit recovers Energy (aka Stamina) lost through movement during a round.
Standing Height (St): Standing height of the unit.
Kneeling Height (Kn): Kneeling height of the unit. Only X-COM soldiers can kneel so technically this stat goes unused for the aliens.
Floating Height (Flt): Determines how high the unit is above the ground. Celatids and Hovertanks are the high-fliers at 6 units while the Floater and Cyberdisc are ground-huggers at 2 units. Surprisingly, Civilians actually float, but you never notice this on a mission.
Damage Modifier (Dmf): This number represents a category each unit uses for determining the susceptiblity to weapons in the game.
Psionic Skill (PSk): Most units have no Psionic Skill and therefore are unable to wage psionic attacks. Sectoid Leaders and Commanders have this ability as do all Ethereals. If you are lucky enough to capture and interrogate one of these aliens your soldiers can also get this ability through training.
Psionic Strength (Pst): A number between 0 and 100 which indicates how well a unit can use and resist psionic attacks.
Motion Scanner Blip Size (Msb): For every tile a unit moves, it gets this value added to a counter in unitref.dat. The bigger the number, the bigger the blip the Motion Scanner will show.
Victory Points (VPS): Points received when you kill that unit.
Aggression (Agg): A rating of 0-2 which determines how aggressive an alien is. High ranking aliens have low aggression while the "grunts" get the higher numbers.
Intelligence (Int): A number between 2 and 8 which indicates how long an alien will remember the location of a unit once spotted.

Editing Alien Stats

If you have a Geoscape and Tactical executable, alien stats start at non-offset byte 379,729 in the Geoscape. The CE version has a single unified executable called "UFO Defense" in which the alien stats start at non-offset byte 480,145. Both have 33 records of 39 bytes each.

Byte Represents Values Unitref Zombie† 0 Race 3-16 [000] 17 1 Rank 0-7 [042] 7 2 Unknown 1 0 [011] 0 3 Flying 0-1 DNA 0§ 4 Time Units 35-110 [025] 40 5 Health 30-148 [026] 84 6 Stamina 65-140 [027] 110 7 Reactions 20-75 [028] 40 8 Strength 20-110 [017] 84 9 Firing Accuracy 0-100 [023] 0 10 Throwing Accuracy 0-80 [024] 0 11 Melee 50-85 [057] 80 12 Front Armor 0-145 [029] 4 13 Left Armor 0-130 [030] 4 14 Right Armor 0-130 [031] 4 15 Rear Armor 0-130 [032] 4 16 Under Armor 0-100 [033] 4 17 Unknown 2 0 [034] 0 18 Energy Recharge 20-50 [035] 20 19 Unknown 3 0 [036] 0 20 Unknown 4 1 ? 1‡ 21 Inventory Layout 0 [046] 0 22 Unknown 5 2-5 [048] 3 23 Unknown 6 2-5 [052] 3 24 Standing Height 10-23 [049] 18 25 Kneeling Height 10-18 [050] 18 26 Floating Height 0-6 [051] 0 27 Damage Modifiers 1-12 [055] 13 28 Psionic Skill 0-60 [037] 0 29 Psionic Strength 5-100 [057] 80 30 Bravery 0-3 [059] 0 31 Motion Scanner Size 3-30 [061] 4 32 Unknown 7 0-1 [071] 0 33 Unknown 8 0 ? 0‡ 34 Corpse Type 50-79 [038] 57 35 Size 0-1 DNA 0§ 36 Victory Points 10-40 [039] 18 37 Aggression 0-2 [044] 2 38 Intelligence 1-8 [073] 3

Record Alien/Unit 1 Floater Soldier 2 Floater Navigator 3 Floater Medic 4 Floater Engineer 5 Floater Leader 6 Floater Commander 7 Reaper Terrorist 8 Sectoid Soldier 9 Sectoid Navigator 10 Sectoid Medic 11 Sectoid Engineer 12 Sectoid Leader 13 Sectoid Commander 14 Snakeman Soldier 15 Snakeman Navigator 16 Snakeman Engineer 17 Snakeman Leader 18 Snakeman Commander 19 Ethereal Soldier 20 Ethereal Leader 21 Ethereal Commander 22 Muton Soldier 23 Muton Navigator 24 Muton Engineer 25 Tank 26 Male Civilian 27 Female Civilian 28 Chryssalid Terrorist 29 Silacoid Terrorist 30 Celatid Terrorist 31 Sectopod Terrorist 32 Cyberdisc Terrorist 33 Hovertank

^† This column represents the theoretical stats for the Zombie which may or may not be found in the executable. All stats were collected by looking at unitref offsets which should hold.
^§ Flying ability and size information are not found in unitref, but we can safely derive them through logic.
^‡ These values do not have a corresponding unitref offset but since all the aliens have the same value it should be safe to assume the Zombie inherits them too.
As of yet, there are still eight unknown byte fields. They are summarized below.

• Unknown 1 (byte 2): Always 0. Probably is some sort of flag. Corresponds to Unitref[011].
• Unknown 2 (byte 17): Always 0. Corresponds to Unitref[034].
• Unknown 3 (byte 19): Always 0. Corresponds to Unitref[036].
• Unknown 4 (byte 20): Always 1. No corresponding Unitref offset.
• Unknown 5 (byte 22): Corresponds to Unitref[048], values are 2-5. Possible width field?
• Unknown 6 (byte 23): Corresponds to Unitref[052], values are 2-5. Identical to Unknown 5.
• Unknown 7 (byte 32): Corresponds to Unitref[071]. Everything 0 except for Cyberdisc which is 1. It's not explosion related.
• Unknown 8 (byte 33): Always 0. No corresponding Unitref offset.

Additional Stats

The following information is found in the UFO Defense executable starting at non-offset 447,868 consisting of 8 records having 20 bytes each. Or if you have the DOS version, it can be found in tactical.exe starting at 391,278. These stats are mainly the in-built weapon turrets for tanks and aliens. Accuracy and TU costs are given as percentages.

Unit	Damage Type	Ammo Type	Damage	Snap Acc.	Snap TU's	Auto Acc.	Auto TU's	Aim Acc.	Aim TU's	Blaster Eff?
Tank/Cannon	0	4	60	60	33	0	0	90	80	0
Tank/Rocket Lnchr	2	12	85	55	45	0	0	115	75	0
Tank/Laser Cannon	3	17	110	50	33	0	0	85	75	0
Hovertank/Plasma	4	36	110	86	30	0	0	100	60	0
Hovertank/Launcher	2	40	140	0	0	0	0	120	80	1
Celatid	7	38	140	75	30	0	0	110	60	0
Cyberdisc	4	34	130	75	30	0	0	110	60	0
Sectopod	3	34	100	75	30	50	35	110	60	0

Damage Type Value Armour Piercing 0 Incendiary 1 High Explosive 2 Laser 3 Plasma 4 Stun 5 Melee 6 Acid Spit 7

Turret damage types for aliens and tanks follow the same damage types for normal weapons. With a little testing on my part, it was determined that the value of 6 was melee. Editing these values only changes the type of damage the weapon inflicts, not what the bolt looks like coming out of the turret. It is interesting to note that the Sectopod's damage type is 3 which corresponds to laser, not plasma as is often assumed.

Firing Accuracy Stats

Firing "Accuracy" is a little confusing, but hopefully this will clear up any confusion. The first type of accuracy is weapon firing accuracy. This is the accuracy of the weapon iteslf. Next is unit firing accuracy, which is how well (or how proficient) the unit can fire a weapon. These two accuracies are then multiplied together to get a "base chance to hit" (or BCTH). BCTH is the unmodified accuracy you see when clicking on a weapon.

Terrorist with integrated weapons have a firing accuracy which works in the same manner. The "turret" weapon accuracy is multiplied by the terrorists firing accuracy leading to a BCTH. These numbers are what the unit will see during a mission for firing accuracy.

Alien	Shot Type	Beg.	Exp.	Vet.	Gen.	Sup.
Celatid	Auto	DNA	DNA	DNA	DNA	DNA
	Snap	37%	79%	84%	88%	93%
	Aimed	55%	116%	123%	129%	136%
Sectopod	Auto	15%	31%	33%	35%	37%
	Snap	22%	47%	50%	52%	55%
	Aimed	33%	69%	73%	77%	81%
Cyberdisc	Auto	DNA	DNA	DNA	DNA	DNA
	Snap	22%	47%	50%	52%	55%
	Aimed	33%	69%	73%	77%	81%

Melee Stats

There are four aliens in the game which rely on melee (or Hand To Hand) as their primary attack method. It was determined that a single HTH attack costs a constant 15 TU no matter what the alien, their stats, or the skill level. It is therefore possible to construct a table showing how many attacks each alien could wage in a single round:

Alien	Damage	Beg.	Exp.	Vet.	Gen.	Sup.
Reaper	90	4	4	4	4	4
Chryssalid	110	7	7	7	8	8
Silacoid	70	2	2	2	2	3
Zombie	84	2	2	2	2	2

Accuracy of melee attacks is not guaranteed to be a successful event, even though the alien needs to be standing on a tile next to your unit. Calculating melee accuracy is very similar to firing accuracy determinations (see above), except that in melee accuracy, you multiply the melee accuracy stat by the units strength rating. The result is the infamous base chance to hit. Note that because both of these stats increase with respect to skill level, the BCTH jumps fairly fast. In fact, at Genius and Superhuman skill levels, the Chryssalid is more than 100% accurate leading to automatic success (zombification).

Alien	Beg.	Exp.	Vet.	Gen.	Sup.
Reaper	72%	75%	79%	84%	89%
Chryssalid	88%	92%	98%	103%	108%
Silacoid	56%	58%	61%	65%	69%
Zombie	67%	67%	67%	67%	67%

Psionic Stats

There are two alien races which possess psionic abilities: Ethereals and Sectoids. All Ethereals and the Sectoid Leaders and Commanders have this attribute. It was determined that a single psionic attack costs a constant 26 TU no matter what the alien, their stats, or the skill level. It is therefore possible to construct a table showing how many attacks each alien could wage in a single round:

Alien	Beg.	Exp.	Vet.	Gen.	Sup.
Sectoid Leader	2	2	2	2	2
Sectoid Commander	2	2	2	2	2
Ethereal Soldier	2	2	2	2	3
Ethereal Leader	2	2	2	2	3
Ethereal Commander	2	2	2	2	3

To generalize, each alien can wage two psionic attacks per round. Only Superhuman Ethereals can wage three.

Acknowledgments

A project of this size and magnitiude could never be completed without some help. I would like to extend my deepest thanks and gratitude to the following individuals:

NKF for his "lemon" psi stat viewer.
Bomb Bloke for his "dump" unitref viewer/logger.
Hatfarm for his excellent editors.
Stewart for providing the original 1.0 executable for testing.
MikeTheRed for for cracking the core stats from each executable version and invaluable technical assistance.