Belt transport system - Factorio Wiki (2024)

The belt transport system is the first system the player will use to transport items from place to place. It, along with trains, and Logistic robots, makes up the systems of item transportation in Factorio.

Belts specifically are used to transport items and run without using energy. Belts can also interact with other moving entities such as players, vehicles and enemies, also allowing for faster or slower movement speed.


  • 1 Belt tier overview
  • 2 Belt mechanics
    • 2.1 Merging and un-merging belts
    • 2.2 Lane balance
    • 2.3 Belt throughput
    • 2.4 Belt tricks
  • 3 Splitters
    • 3.1 Mechanics
      • 3.1.1 Priority
      • 3.1.2 Filter
    • 3.2 Balancing
    • 3.3 Manipulating belt lanes
  • 4 Circuit network
  • 5 Underground belts
    • 5.1 Separating belt lanes
    • 5.2 Braiding
  • 6 See also

Belt tier overview

Animation showing the three types of belt and their speed (from top to bottom: regular belts, fast belts, and express belts).

There are 3 different tiers of belts available for use. The transport belt has a yellow color and is the slowest, as well as the cheapest to craft. The next tier up, the fast transport belt has a red color and is twice as fast as the standard transport belt. The express transport belt is the final tier. It is colored blue and is three times faster than normal belts, or 1.5× faster than red belts.

Transport beltsUnderground beltsSplittersMax. throughput
Needed research

Transport belt

Underground belt

15Logistics (research)1

Fast transport belt

Fast underground belt

Fast splitter
30Logistics 2 (research)

Express transport belt

Express underground belt

Express splitter
45Logistics 3 (research)

(1) Only for the underground belt and splitter. The basic transport belt is available at the start of the game.

Regardless of the belt tier, a fully filled straight transport belt holds 8 items in total. For more information on this, see Transport belts/Physics and Friday Facts #276 - Belt item spacing.

Belt mechanics

Merging and un-merging belts

Belts of all tiers have 2 lanes for items to ride on. This allows for either a double flow of one material, or to transport two different materials on the same belt. Mixed belts can be beneficial forsmelting ore, or producing items with many different ingredients such as Utility science pack. The belt can be unmerged using a splitter filter. It is also possible to unmerge a mixed belt by using underground belts since an underground belt will block half of the belt.

Belts going across a splitter will have items from the splitter moving to one side of the crossing belt.

Commonly, merging and un-merging is done by using a splitter. The trick in the second gif is better described in the underground belt section.

Lane balance

Due to how items are placed onto belts by inserters, their lanes can sometimes become unbalanced. In order tomaintain throughput, balancing the lanes may be necessary. The gifs below show two ways how to do this. The former only works if only one lane is in use initially. For further explanation of the mechanics, see lane balancers.

Belt throughput

4 stack inserters can compress an express belt at stack size 12 for the left inserters and stack size 8 for the right inserters.

Maximizing the throughput means ensuring that as many items as possible are transported. Therefore some definitions need tobe introduced:

How fast a belt moves in tiles per second. This is 1.875, 3.75 and 5.625 for basic, fast and express belts.
How tight are the items put onto the belts; each straight belt piece can hold exactly 8 items.
This is speed × density. It describes how many items pass by at a given time.

So, there are three opportunities to enhance the throughput:

More density
Sometimes items have small gaps in between each other that aren't big enough for other items to fit in. However, mining drills, inserters, and belt sideloading can still force an item into these gaps, temporarily squashing the items on the belt. The squashed gap is extended to normal size once the front of the belt starts to move again.
More speed
If the belts in the factory are already at maximum density, their speed can still be upgraded with better belts. Finding the bottleneck is the first thing that needs to be done, usually it can be discovered quite easily. There will be a part of the belt where the items don't move quickly (or at all) or stop at maximum density and suddenly they come to a point where this 'stop and go' effect releases itself, the bottleneck has been found. In most cases, this will be the place where belt optimization is needed.
More belts
Adding additional parallel belts can also increase the throughput. Simply place more belts carrying the item that needs throughput.

Belt tricks

Moving fast can be essential to defend alien attacks in time. Running on a belt will increase or decrease the movement speed of the player accordingly to the belts speed. That is why building a belt towards your defenses can be beneficial.

However, the player is not the only unit that can be moved by transport belts. Additionally, biters and spitters can be moved. This can be abused to improve your defense. Firstly, biters will have a harder time to reach your walls when placing express transport belt in front of them. Secondly, spitters can be moved closer to your walls. That way more turrets can attack a single spitter at once.

Another useful usage is cars on transport belts. Cars have an inventory and can be filled by inserters. So, they can be used as moving boxes on belts. This has several advantages: Firstly the throughput of the belt-car-boxes is amazingly high, secondly the inserter stack size bonus does apply here and makes inserters more effective.


Splitters are another form of item manipulation. Splitters are a 2×1 entity that splits incoming items on beltsfrom up to two input to up to two outputs, in a 1:1 ratio. They are used to divide resources between two belts, or balancemultiple belts.


The behavior of splitters looks simple at first glance. But they are not that simple. Splitters have an astonishing amount of uses.

  • Splitters have two input belts and two output belts. If the splitter receives items on one belt, it will split the input evenly between its two outputs. If one of the outputs is fully backed-up and the splitter cannot split evenly, it will put all input on its other output.
  • Splitters can also merge belts, taking two inputs and one output.
  • Splitters preserve the lanes of the items, by moving through the splitter an item on the right lane will not be moved to the left lane, and vice versa.
  • Splitters can prioritize one input and/or one output. Clicking on a splitter opens its GUI where the priorities can be set.
  • One output of the splitter can be filtered to one item. Items of that type will only go to that output, and not to the other one.

The speed of the splitter is the same as its relevant type of belt, so in order to properly join/split belts, the splitter must be the same speed as the incoming belts. Otherwise the splitter will become a bottleneck.


For both the input and output side of the splitter it is possible to set the priority to either left or right.

A splitter where the input priority has been set will first try to consume the specified input side, and will onlyconsume the other input once there is a gap on the prioritized input belt.

Similarly a splitter where the output priority has been set will try to redirect all incoming itemsto the specified output, and will only output on the other output once the specified output is full.


If a specific item is set in the splitter's filter slot, the slider for the output priority willbe used for the filter instead. All items of the set type will be redirected to that specific outputand all other items are directed to the other output. The input priority can be set independently of the filter.


Main article: Balancer mechanics

Balancers are used to evenly distribute items over multiple belts or multiple belt lanes.

Manipulating belt lanes

  • Swapping lanes on a belt with a different item per belt lane.

  • Separating lanes with different items on them.

Circuit network

Two belts connected to a constant combinator.

Red or green wires can be connected to segments of transport belts to use them as part of a circuit. Belts connected to the circuit network will appear with a yellow cage above them, with a moving red scanner within it. When a belt is connected to a circuit, a GUI can be accessed from the connected belt for settings on how the belt will be used for a circuit; there are two modes of operation that can be used:

Enable/disable - A circuit condition dictates whether or not the belt will allow items through.
Read belt contents - If enabled, the contents on the belt will be read.

The belt's GUI will also have a "content read mode" setting, which can be set to either pulse or hold. Pulse will read the belt's contents for only one tick, while hold will read the belt's contents continuously on every tick.

Transport belt GUI.

  • A small example of a transport belt circuit reading belt contents to trigger two lamps.

  • Fast inserters are activated by the arithmetic combinators' setup; when a specific item enters a belt segment that's connected to the circuit network, the inserters place the same item on another belt.

Underground belts

Underground belts can be used to cross different flows of items without interfering. They move items like a normal belt.

Underground lengths

  • Underground belts can cross any number of entities and all types of ground, like water and grass. (as long as the input and output endpoints are on land)
  • Underground belts can cross other underground entities (any number of underground belts or underground pipes). They won't be mixed.
  • For the connection only the endpoints (entry-side and exit-side) are relevant.
  • The underground distance is 4, 6 and 8 tiles, respectivly, for the three belt types.
  • An underground belt pair that bridges a gap of 4 tiles stores up to 44 items. An express underground belt pair at max length stores up to 72 items.
  • The half of the underground belt tile with a belt can accept input from the side. The other half (with a tunnel entrance) blocks incoming items.

Separating belt lanes

  • This is built by placing one underground belt and then using R to reverse its direction. This converts the underground belt entrance to an exit (and vice versa).

  • This can also be used to split the lanes of a belt onto seperate belts instead of using a splitter filter.


  • Different types of underground belts can be braided together along the same line of tiles, with items staying in their respective belt types.

  • The same concept, but with a different belt design.

Braiding can be particularly useful where more than two input lanes are required while also avoiding the use of a parallel belt/long-handed inserter combination. For example, this can be useful if there is limited space, such as when using a beacon. With a beacon range of 3 orthogonal tiles, two of which would be occupied by a belt and inserter, it would not be possible to place the parallel belt in the third space and still have a beacon on the same side, as the assembler would now be in the fourth tile and not in range. With the space saved by braiding, this is now possible.

See also

  • Splitters
  • Transport belts
  • Underground belts
Belt transport system - Factorio Wiki (2024)


Is there a limit to the number of items on a belt Factorio? ›

It is colored blue and is three times faster than normal belts, or 1.5× faster than red belts. Only for the underground belt and splitter. The basic transport belt is available at the start of the game. Regardless of the belt tier, a fully filled straight transport belt holds 8 items in total.

Are trains faster than belts Factorio? ›

Trains are faster than belts and offer better logistic control as you go between logistic networks.

How do you use both sides of a transport belt in Factorio? ›

Use a splitter to evenly distribute items between both sides of the belt. Good for places the belt doesn't move non-stop. If one side of the belt fills up, all items will goto the other side and buildings will keep running.

How many items to fill a belt Factorio? ›

Belt properties

How many items fit onto a certain length of belt, measured in items per tile per belt lane. This is 4 on a straight belt, regardless of the type of item and type of belt. The item density on belts can be different from what they take up when just dropped on the ground (using the Z key).

How many miners for a full yellow belt Factorio? ›

Second, miners (in vanilla) put out one item every 2 seconds. This sets a mathematical limit on how many active mines a belt can handle : 30 mines on a yellow belt, 15/side; 60 mines on a red belt, 30/side, and 90 mines on a blue belt, 45/side.

How many items can a red belt transport? ›

Some numbers to keep in mind, a yellow belt is capable of transporting 15 items per second (7.5 per side), red belts are twice that (30 per second) and blue belts are three times that (45 per second). It is good: when your output is overloading current belt.

How long does it take to 100% Factorio? ›

When focusing on the main objectives, Factorio is about 49½ Hours in length. If you're a gamer that strives to see all aspects of the game, you are likely to spend around 221 Hours to obtain 100% completion.

Can Factorio trains go backwards? ›

Trains can only drive forwards automatically. An automatic train can drive forwards and backwards when two locomotives facing different directions are connected to the train.

Can trains collide in Factorio? ›

Whenever there is more than one train on a track, there is the possibility that trains can crash into one another.

How to merge 2 belts into 1 Factorio? ›

You can combine two parallel belts with a splitter and only use one output belt, they'll merge. If you have 2 belts feeding horizontally into a vertical belt or two feed vertically into a horizontal belt they will merge. Each side will deposite items on its belt to one side of the merged belt.

What is the belt to miner ratio in Factorio? ›

As for miners, 1 miner provides 0.5 ore/second so 30 for a yellow belt or 60 for a red. Practically, you just want to pack in as many miners as you can.

How do you split a full belt in Factorio? ›

One of the most common methods for splitting a belt in Factorio is to use a splitter. Splitters are machines that can balance two belts together, divide one into two, or combine two into one. Each of their two inputs and two outputs will receive the same quantity of the commodities flow.

What is the yellow belt max in Factorio? ›

For those unaware, . 17 changed belts speed/capacity. Yellow max throughput is 15 items a sec, red is 30/s and blue is 45/s.

Can Factorio make water? ›

The primary method of extracting water in Factorio is through the use of offshore pumps. To begin, you will need to craft these pumps using the following materials: 0.5 iron plates. 2 electronic circuits.

What is the max inventory size Factorio? ›

The character's maximum health is 250 (without energy shields). The player's health can naturally, slowly regenerate a few seconds after taking damage. The character's main inventory has 80 slots (without bonuses from power armor, toolbelt research, or logistic trash slots).

How do I know if my Factorio belt is full? ›

A greenlight means you have a fully saturated belt, a Redlight means you do not have a fully saturated belt. This is useful for checking to see if your custom assemblies are achieving full belts.

Are resources in Factorio Limited? ›

All resources are found in finite groups. However, infinite groups of resources may be found on your world.

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