Quality

	This article contains content on features that will be included in a future update.
	These features are confirmed, but not yet added to the game.

Quality positively influences the effects of items and buildings, allowing for "vertical" improvement in order to create smaller factories for a given output.

Quality is a random effect from quality modules, similar to Uranium processing, and not cumulative like productivity.

Quality Tiers

There are 5 quality tiers in vanilla gameplay, with tier strength in brackets:

• Normal (0)
• Uncommon (1)
• Rare (2)
• Epic (3)
• Legendary (5)

All vanilla quality tiers have a 0.1 chance multiplier, which is used when crafting with quality modules.

Quality Effects

The currently known effects of quality strength are as follows:

• +30% health
• +30% energy output
• +30% crafting speed
• +30% robot limit (rounded down)
• +30% robot recharge rate (both number and speed, rounded down)
• +30% positive module effects (rounded down for at least quality modules)
• +10% turret range
• +1 tile reach for power poles
• +1 equipment grid size (both dimensions)
• Larger inventory (unknown boost size)
• Increased ammo damage (30%?)
• Faster inserters
• Reduced resource depletion on miners (likely multiplicative in effect with productivity)
• Larger capacity on accumulators
• Increased output rate on nuclear reactors, boilers, and steam engines/turbines
• Reduced power consumption on beacons
• Larger scan range on radars
• +100% durability on consumable items (repair packs, science packs)

These effects are per quality strength and additive, a Legendary Productivity module 3 would grant 25% productivity.

Some buildings, such as Transport belts and Walls, only gain increased health.

Quality Modules

Quality modules add 10%/15%/25% quality strength to a crafting machine, which allows resulting items to be a higher quality.

When working out the odds of improving quality, start with the sum of quality strength, then for each quality improvement multiply by the tier chance multiplier (0.1 for all vanilla tiers).

For 100% quality strength on Normal inputs with all tiers unlocked, this gives the following odds:

• 90% Normal
• 9% Uncommon (10% Uncommon+)
• 0.9% Rare (1% Rare+)
• 0.09% Epic (0.1% Epic+)
• 0.01% Legendary

For 248% quality strength (maximum possible as +150% on 25% rounds down to 62% per module), the odds are instead:

• 75.2% Normal
• 22.32% Uncommon (24.8% Uncommon+)
• 2.232% Rare (2.48% Rare+)
• 0.2232% Epic (0.248% Epic+)
• 0.0248% Legendary

When using quality ingredients as an input, the base quality is the lowest input quality ignoring liquids (as fluids cannot have quality). Crafting an Electronic circuit from Uncommon Iron plates and Epic Copper cable will give a base quality of Uncommon.

Quality modules are only required to improve quality, crafting will always give the base quality of the used items. Additionally, the odds of improving from a given base quality is (in vanilla) the same as improving the same number of tiers from Normal quality.

Optimal Module Usage

When using Assembling machine 3s with the goal of converting all input items to Legendary outputs, and feeding non-Legendary items through a Recycler with 4 quality modules (as recyclers can't take quality modules), the optimal number of quality and productivity modules is as follows:

• If the quality modules offer less than 15% strength, use 4 quality modules
• If the quality modules offer 16% (Rare T3s) or 19% (Epic T3s), use 3 quality modules and 1 productivity module
• If the quality modules offer 25% (Legendary 3s), use 2 of each module
• If the quality modules offer exactly 15% (Legendary T2s):
  • When the base quality of the inputs is Epic, use 4 quality modules
  • When the base quality of the inputs is not Epic, use 3 quality modules
    • If the productivity modules offer 1.5% or less and the base quality of the inputs is Rare, use 4 quality modules and not 3

It is also more optimal to improve quality on the lead-up to the target output item due to the recycler only giving back 25% of the input items, except for cases where the chosen item has a productivity research available, in which case looping through a recycler is optimal and has no added material cost (ignoring fluids).