Time units or TUs are one of several vital resources available to X-COM Soldiers.
A single game turn is an unspecified amount of time. There has been many arguments as to what duration of time this could be, but no one can agree on a hard figure. Here's one example of a detailed estimate. Maybe it's a minute, maybe it's 5 seconds.
In any case, a game turn is merely the duration in which actions are taken by each side.
The Time Unit is a fraction of this time. If a soldier has a maximum of 64 Time Units, then each TU is worth 1/64th of a turn. A soldier with 80 TUs uses 1/80th of the turn for every TU spent. This means that Time Units are synonymous with speed.
New recruits always begin with a value from 50 to 60 time units.
TU points are awarded (at end of mission) any time you perform at least one primary action. Just one action is enough - additional ones do not cause more TU points to be awarded.
The possible points earned are dependent on your current TUs. At recruit minimum (50 TUs), an average of 2.2 points are earned. This slopes evenly down to where, at cap minus one (79), an average of 1.0 points are earned (range 0-2).
A soldier's TUs caps at 80, but it is possible to 'overflow' the cap by one point on the last combat when you go over the cap (in other words, 79 plus 2 gives you 81). You have around 33.3% chance of getting capped at 81 and around 66.7% of getting capped at 80. The mathematics is like this.
50% +1 to base TU -> 25% +3 to base TU -> 25% +2 to base TU ->12.5% +3 to base TU ->12.5% +4 to base TU 50% +2 to base TU ->25% +3 to base TU ->25% +4 to base TU
As you progress towards infinity it heads towards the two thirds and one third chance.
Older versions of X-COM did not have a cap and stats could reach 255 and then wrap back to 0. This could potentially cripple an otherwise good soldier.
Time Unit Expenditure
Time Units are spent in two ways. In fixed amounts and in percentages.
Actions such as walking, turning, moving inventory around, reloading weapons, and using the medkit all cost the same fixed amount of TUs for all soldiers. Soldiers with high TUs benefit the most from fixed TU actions. I.e., they represent the speed of solder's physical actions.
|Accessing Medikit Panel||0|
|Turning in place 45 degrees||1|
|Turning during reaction fire||0|
|Standing after kneeling||8|
|Unloading a weapon||8|
|Changing elevation in a Flying Suit or grav lift||8|
|Using a Medi-kit charge||10|
|Reloading a weapon||15|
|Using a Psi Amp||25|
|Walking||Dependent on terrain, from 4 to 18TUs per square; diagonal movement costs 50% more. Refer to the walking cost table|
|Moving items in the inventory||Variable. Refer to the inventory movement cost table|
Actions that cost a percentage, such as firing a gun or priming a grenade, will always take a percentage of the soldier's base Time Units to perform. It represents the speed of devices used, a specific amount of time independent of the solder's physical abilities. This means that the soldier's base TUs has no bearing on how many times the action can be performed during any given turn.
For example, if a weapon costs 25% to fire, it can only be fired a maximum of 4 times a turn, for every soldier, regardless of his/her amount of TUs. Because of this, it's smart to put low-TU soldiers in long range fire support roles.
Note: Costs are based on the maximum amount of your soldier's TUs, not the current amount. Therefore, percentage costs do not change as you use up TUs (or if you have more TUs than usual, due to going berserk).
Note: Due to integer rounding, some TU values will allow certain weapons to be fired more than usual. For example, a soldier firing a Heavy Plasma with auto-fire (35% TUs) will get 3 rounds at some rare MaxTUs values (only at 51, 54, and 57) but not at any others. More often seen, a Laser Rifle's 34% is more likely to allow this "bonus shot".
|Firing any weapon||Depending on weapon and firing mode from 18% up to 80%|
|Using Motion Scanner||25%|
|Using Stun Rod||30%|
|Using Mind Probe||50%|
|Priming an explosive||50%|
Encumbrance is the weighing down, or burdening, of a soldier. Any weight over the soldier's strength stat will cause encumbrance. This lowers their available TUs, essentially slowing them down.
Encumbrance = Strength / Carried Weight* If Encumbrance >= 1 then Available TUs = Base TUs Else Available TUs = INT(Encumbrance x Base TUs)
* If Carried Weight = 0, then Carried Weight = 1
A low-end Rookie with a base of 50 TUs, 20 strength, and carrying 80 weight units, will have an encumbrance of 25%, leaving him with a meager 12 TUs per turn.
Each fatal wound to the left or right leg reduces the soldier's TUs by 10%.
- Time Units heavily influences a unit's Reactions.
- Closely associated with TUs is the Energy stat.
- A moving unit consumes both TUs and Stamina (Energy) points. How many energy points are consumed depends on the type of terrain the unit is walking on. More difficult terrain consumes more energy and time units. All other actions only consume TUs. The sole exception is that some aliens use Energy for turning around as well and can provoke reaction fire by just turning around while a soldier cannot.
- Energy recovery is calculated by taking your soldier's initial time units (the TUs they had as a new recruit) and dividing this by three. Drop the fraction. This will be the soldier's energy recovery rate throughout the campaign. For more details, see Energy.
Time Unit Walking Usage Tables
Refer to the Walking Costs table.
|X-Com: Enemy Unknown/UFO Defense|
|Soldiers:||Time Units • Energy (Stamina) • Health • Bravery • Reactions • Firing Accuracy • Throwing Accuracy|
|Strength • Psionic Strength • Psionic Skill • Melee Accuracy • Stun • Morale • Rank • Fatal Wounds|