Inserters

For the common yellow electrical inserter, see Inserter.

Inserters are devices which are used to move items over short distances. When placed, they have a fixed direction. They can move items from behind and place them in front of them. By doing this, they can move items from one transport belt to another, but also extract items from—and insert items into—machines or storage devices.

Types of inserters

Burner inserter	The only fuel-powered inserter, with the slowest speed.
Inserter	The standard electrical inserter.
Long-handed inserter	Capable of inserting and removing items from a greater distance.
Fast inserter	Much faster than the inserter.
Bulk inserter	As fast as the fast inserter, but can move many more items at the same time at once.
Stack inserter	As fast as the bulk inserter, but can stack items on a belt.

Mechanics

Inserters will:

• Pick up items off the ground, off of a transport belt, or from any object that has storage space, including chests, furnaces and assembling machines.
• Place the item onto the ground, onto a transport belt, or into any object that has storage space.
• Run at slower speeds when starved for energy.
• Pick up as many items as their stack size allows at once, if they do not have to wait too long to pick them up.
• Pick up items and drop them into the void of space or lava, permanently discarding them. This is useful for getting rid of unwanted items.

Inserters will not:

• Pick up any items that cannot be inserted into the adjacent entity.
• Pick up any items if the adjacent entity is a ghost.
• Pick up items to place into an entity with a full inventory.
• Place more than one item at a time onto the same ground tile.
• Place items into an entity that cannot hold them, for example due to filtered or limited slots.
• Fill up the entire target inventory of boilers, nuclear reactors, production buildings, furnaces and turrets.

If two or more inserters are picking up from the same tile, the inserter who can grab the items the fastest will grab them first. Besides faster inserters, this favors inserters taking from the inner lane of a transport belt.

Insertion limits

Depending on where an inserter is moving items, it does not always fill up the entire target inventory. This allows other inserters taking from the same transport belt to pick up their share of the items. For example, if a boiler has 5 or more items of fuel in it, an inserter will not insert additional fuel. This allows the other fuel to travel further down the transport belt. When the fuel drops below 5 items, the inserter will resume inserting fuel, up to the limit of 5 items.

Entity	Item type	Automatic insertion limit
Boilers, burner inserters, furnaces, and nuclear reactors	Fuel	5
Gun turrets	Bullet Magazines	10
Artillery turrets	Artillery shells	5
Assembling machines, furnaces, centrifuges, chemical plants, and oil refineries	Items needed for the recipe	The ingredients for 1 craft in addition to the ingredients for the number of crafts that can be completed during one full inserter swing; but at least the ingredients for 2 crafts and at most the ingredients for 100 crafts.[1]
Labs	Science packs	The number of science packs needed for one research unit in addition to the science packs for the number of research units that can be completed during one full inserter swing; but at least the ingredients for 2 research units and at most the ingredients for 100 research units.

An inserter that has a higher inserter capacity bonus than 1 can overfill the target building, due to the inserter picking up a higher amount of items than needed. Overfilling can also occur if multiple inserters are used to insert items into one building.

Inserters and transport belts

Transport belts have two lanes on which items can travel. Inserters only place items onto one side of the belt, either the far side from the inserter's perspective or if the belt is going the same or the opposite direction as the inserter the right side from the belt's perspective.

Inserters place the item on the furthest lane. If a belt is in the same orientation as the inserter, the item will be placed on the right-hand lane, from the belt's perspective. In curves the inserter always places on the far side.	If the belt is perpendicular to the inserter, inserters prefer taking items from the nearest lane. If the nearest lane is empty, the inserter will take from the far lane. If the belt is the same/opposite orientation of the inserter or a curve, the inserter prefers taking from the left lane, from the belt's perspective. If the left lane is empty it will take from the right lane.

Potential issues

Inserters may have problems picking up items:

• From very fast belts, because the items are moving too quickly.
• From the entry or exit of an underground belt (because the time they have to pick up is shorter)
• From turning belts if the item is on the inside of the corner

Power usage

• Electric inserters drain energy even when they are not moving, as idle power
• The amount of energy used is the same for every turn
• The burner inserter does not drain energy when idle, but uses more energy when it is active.

Inserter speed

Animation showing all inserter speeds at once.

Type	Rotation-speed (turns per tick) Extension-speed (Tiles per Tick)	Turns per Game-second	Game-second per full turn	Ticks per full turn
Burner inserter	0.01 0.0214	0.60	1.667	100
Inserter	0.014 0.03	0.83	1.2	72
Long-handed inserter	0.02 0.0457	1.2	0.833	50
Fast inserter Bulk inserter	0.04 0.07	2.31	0.433	26

Note: These numbers come directly from the factorio-data github repository.

Rotation Speed

Convention: 2π rad = 100% of a circle rotation = 1 turn (or one full rotation).

Note: an Inserter doesn't always need to make full turns. When grabbing from a transport belt, it is slightly faster when grabbing items from the closest lane.

Note: If the rotation speed of an inserter would result in an odd number of ticks per full turn, the actual number of ticks per full turn for this inserter is the next higher even number. The reason for this is that the inserter needs to do two half turns to pick and drop an item. This takes a certain number of ticks two times, therefore the number of ticks for the full turn is always an even number. Example: The Fast inserter's rotation speed of 864°/s or 0.04 turns per tick would result in 25 ticks per full turn, but the inserter cannot do a half turn in "12.5 ticks", so it actually takes 2*13 = 26 ticks per full turn.

Extension Speed

The extension-speed is normally not visible (only when compared to other inserters), but there are measurable speed differences when taking - for example - from the near or the far side of a belt. Also Some mods can alter the pickup and drop locations of inserters, making this stat more relevant.

Inserter Throughput

The following is based on experimental data from 1.1. Most of the 1.1 experimental data was gathered using the following circuit blueprint to measure the exact tick difference between inserter swings. A lot of the data on this page (specifically the belt to chest data) relies heavily on the conditions of the setup on which the measurements are done. If your setup differs from the ones tested on this page, you can use the following blueprint to do the measurements yourself.

  Copy blueprint string

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Chest to chest

Note: Experimental data from 1.1

Type	Arm cycles per second	Items/second at capacity bonus level (stack size)
		No capacity bonus		Capacity bonus 2		Capacity bonus 7
Burner inserter	0.60	0.60	(1)	1.20	(2)	1.80	(3)
Inserter	0.83	0.83	(1)	1.67	(2)	2.50	(3)
Long-handed inserter	1.20	1.20	(1)	2.40	(2)	3.60	(3)
Fast inserter	2.31	2.31	(1)	4.62	(2)	6.92	(3)
Bulk inserter	2.31	4.62	(2)	9.23	(4)	27.69	(12)

Chest to belt

Throughput going from chest to belt depends on how full the belt is. An inserter will not put down an item on a belt that have items back-to-back (aka full compression) - it waits until there is a gap. However, if the gap is narrower than the item then the items upstream on the belt will stop to make room for the item being inserted. The direction of the belt compared to the inserter does not matter however.

In these measurements inserters move items onto an empty belt. Values are given for the stack sizes at three different capacity bonus levels.

Note: Experimental data from 1.1

Type	Items/second at capacity bonus level (stack size)
	No capacity bonus				Capacity bonus 2				Capacity bonus 7
Burner inserter	0.60	0.60	0.60	(1)	1.19	1.19	1.19	(2)	1.67	1.73	1.76	(3)
Inserter	0.83	0.83	0.83	(1)	1.64	1.64	1.64	(2)	2.25	2.37	2.43	(3)
Long-handed inserter	1.20	1.20	1.20	(1)	2.35	2.35	2.35	(2)	3.10	3.33	3.46	(3)
Fast inserter	2.31	2.31	2.31	(1)	4.44	4.44	4.44	(2)	5.29	6.00	6.43	(3)
Bulk inserter	4.44	4.44	4.44	(2)	5.71	7.06	7.74	(4)	6.79	10.91	13.85	(12)

Chest to splitter

When an inserter drops items onto the side of a perpendicular splitter, it always is considered to do so on the input side, enabling the splitter to move half of the items to the other belt (assuming that the splitter filter/priority settings allow it to do so and that there is available space on both belts). This allows the inserter to drop its items twice as fast. A fully upgraded stack inserter can drop twelve items onto an express splitter every 38 ticks (18.95 items/second) instead of the usual 52.

By inserting onto the side of a splitter, a fully-upgraded stack inserter can fill 84% of an express belt lane instead of the usual 62%.

Three stack inserters can saturate an express belt if one of them inserts onto a splitter.

Belt to chest (perpendicular)

Note: Experimental data from 1.1

When picking items from a belt, many more factors come into play besides belt fullness:

• How fast the items move (i.e. if they are queued up on the belt or move at belt speed).
• Whether the belt is perpendicular to the inserter or approaches it head on.
• Whether items are on the near or far lane of a perpendicular belt.
• Whether the belt turns or not, and whether the items are in the inner or outer side of the bend.
• If the belt is an underground entrance or exit. This shortens the time items are visible to the inserter for pickup.
• All sorts of intricate timing factors between the inserter and the items on the belt, since the game simulates the arm homing in on every item.

The test setup used below is with an inserter taking items from a perpendicular belt with items on the far lane only. The belt is fully compressed and timings are both for items that move at full speed and queued up as much as possible. Values are given for the stack sizes at three different capacity bonus levels.

Type	Items/second at capacity bonus level (stack size)
	No capacity bonus					Capacity bonus 2					Capacity bonus 7
	Items at belt speed			Items queued up		Items at belt speed			Items queued up		Items at belt speed			Items queued up
Burner inserter	0.60	0.65	0.50	0.64	(1)	1.11	1.20	1.13	1.26	(2)	1.61	1.61	1.65	1.71 / 1.73 / 1.86 *	(3)
Inserter	0.94	0.94	0.94	0.88	(1)	1.67	1.67	1.50	1.74	(2)	2.50	2.25	2.33	2.37 / 2.37 / 2.54 *	(3)
Long-handed inserter	1.18	1.18	1.25	1.20	(1)	2.20	2.31	2.40	2.40	(2)	3.21	3.21	3.46	3.40	(3)
Fast inserter	2.50	2.31	2.50	2.50	(1)	4.50	4.29	5.00	4.80	(2)	6.43	6.00	6.43	6.43	(3)
Bulk inserter	4.50	4.29	5.00	4.80	(2)	7.50	7.50	8.00	7.50 / 8.57 / 8.28 *	(4)	7.50	11.25	15.00	7.50 / 13.09 / 15.32 *	(12)

*) Throughput for basic/fast/express belt.

Since there are many more factors involved, these measurements exhibit a more complex pattern than chest-to-belt.

• Boldface cells show for which belt each inserter has the best throughput on each bonus level when items move at belt speed. Higher speed belts mean that inserters have to work harder to catch the fast moving items. The effect is most noticeable for slower inserters and smaller stack sizes.
• When items are queued up the belt type hardly matters, so there is only a single column for that. The exceptions are the stack inserters - for basic transport belts it's the belt that sets the limit for stack sizes above 4, and there is also a notable difference between fast and express belts.

Belt to Chest (facing inserter)

Note: Experimental data from 1.1

When picking up items from a belt facing the inserter, there are multiple small differences between different setups. The following throughput tests are performed with express transport belts and stack inserters with the maximum capacity bonus. Each setup in the following picture shows the amount of ticks per cycle of the inserter and the amount of items per second the inserter moves. These measurements are consistent in all orientations of the setup.

See Also

• Electric system
• Belt transport system
• Inserter capacity bonus (research): Inserter moves more than an item per turn.