Every ship has the same four power sliders: weapons, shields, engines, and auxiliary. Most players set them once from a build guide and never revisit them. This is what each point of each slider actually buys, so you can change the preset for a specific fight.
| Slider | What each point buys |
|---|---|
| Weapons | +0.5% energy weapon damage (no effect on torpedoes or mines) |
| Shields | +2% of your shield array's regeneration rate, and shields negate 0.2% more of the damage they take |
| Engines | +2% speed above 50, -2% below 50, and more defense rating as speed rises |
| Auxiliary | +1 stealth and 1% hangar pet recharge reduction per point; science ability potency +2% per point above 50, -0.6% per point below |
All ships share a base pool of 200 subsystem power split across the four systems, and raising one lowers another. You can set any system between 15 and 100 by hand, and most have a default cap of 125, which items, traits, and abilities can raise. Power above the cap does not add damage directly, but it is not wasted, as the weapons section explains. Console players get four presets on the D-pad: 100 weapons with 50 shields, 25 engines, and 25 auxiliary, and three variants that put the 100 in shields, engines, or auxiliary instead. On PC you can set any split you like and lock a slider so it does not move when you adjust another.
Weapon power only affects energy weapons. The multiplier on their damage is:
Multiplier = (Weapon Power + 100) / 200
| Weapon power | Damage multiplier |
|---|---|
| 50 | 75% |
| 75 | 87.5% |
| 100 | 100% |
| 110 | 105% |
| 125 (default cap) | 112.5% |
Going from 100 weapon power to the 125 cap raises energy damage from 100% to 112.5%, a gain of 12.5%. Going from 75 to 100 is a gain of 14.3%, because you are adding 25 points to a smaller base. That is why a build that sits at 75 weapon power to afford more of another system gives up more than it looks like, and why a small boost, such as Emergency Power to Weapons, matters for as long as it lasts.
Firing an energy weapon also temporarily deducts its power cost from your current weapon power for the length of its firing cycle, and refunds it at the end. The interesting part is overcapping: any weapon power above your cap acts as a backup pool that refills what your weapons are using, at your power transfer rate. For example, with 150 power and a cap of 125, you fire eight beams costing 80. Your power drops from 125 to 45, then climbs back toward 70 during the cycle as the 25 points of overcap refill it, and jumps to 125 when the cycle ends. Without the overcap it would stay at 45 the whole time.
The shield subsystem does not change how big your shields are. It changes how fast they regenerate and how much damage they absorb. Each point gives 2% of the regeneration rate shown on your shield array, so 50 power is 100% of it, and each point makes your shields negate 0.2% of the damage they take, so 50 power is 10% hardness. Both scale linearly, so it is easy to see what a slider change buys.
Engine power sets your speed: 50 power is base speed, each point above adds 2%, and each point below removes 2%. Speed also raises your defense rating, which is one reason pilot ships run engines high. Two related mechanics are worth knowing. Flying in reverse for more than 10 seconds builds a Reverse Power Drain that removes 1 power per second from every subsystem, up to 25 points each. And Full Impulse routes almost everything to engines and drops weapons, shields, and auxiliary to 5, so entering combat at Full Impulse leaves your weapons badly weakened until power is rerouted.
Auxiliary does more than it looks like. Engineering abilities that use auxiliary, such as Auxiliary Power to the Structural Integrity Field, scale with it as well. That is why exotic builds try to push auxiliary well past 100, and why a common energy build sits at 70 rather than dumping everything into weapons.
Take the community baseline for a PC energy build: 100 weapons, 15 shields, 15 engines, 70 auxiliary. From power alone, that gives 100% weapon damage, shields at 30% of their listed regeneration and 3% hardness, engines at 30% of base speed, and science abilities at +40% potency.
Now the first console preset: 100 weapons, 50 shields, 25 engines, 25 auxiliary. That gives the same 100% weapon damage, but shields at 100% regeneration and 10% hardness, engines at 50% of base speed, and science abilities at 15% below normal (25 points under 50, at 0.6% each). Both spend exactly 200 points. The first trades survivability and speed for science ability potency, and the second trades that potency for shields. These figures come from power alone, before skills, traits, and items add their own bonuses.
You rarely play at bare slider values. Skills, warp cores, engines, deflectors, and traits add power on top of your slider, and some add to the cap. Performance skills give a flat amount to a subsystem. Efficiency skills give a larger bonus the lower a subsystem is set, which is why running a system low costs less than the raw slider numbers suggest. The Electro-Plasma System, or EPS, controls how fast power moves between subsystems, and an EPS Flow Regulator console or the Engineering captain's EPS Power Transfer ability speeds that up. Auxiliary Power to the Emergency Battery is a good example: at rank III it adds 19 power to weapons, shields, and engines for 10 seconds while removing 45 from auxiliary.
Energy builds want weapons at 100 with auxiliary as the second priority. Exotic builds want auxiliary as high as they can get it. Pilot ships, like the Fleet Nova build described in the exotic guide, lean on engines, and tanks published by the STO BETTER community run high weapons and high auxiliary with moderate shields. To test a change, record a run with the /CombatLog command, change one slider group, record again, and compare in the Combat Log Reader. For the abilities that move power around mid-fight, see Cooldown Reduction Mechanics, and for how weapon power fits an energy build, read The Anatomy of a Meta Energy Build.