What is the Worldwide LHC Computing Grid?

The Worldwide LHC Computing Grid (WLCG) is a distributed computing infrastructure to provide the production and analysis environments for the LHC experiments.

It is managed and operated by a worldwide collaboration between the experiments and the participating computer centres. The resources are distributed across the world for funding and sociological reasons.

Our task is to make use of the resources available to us – no matter where they are located. We know it would be simpler to put all the resources in one or two large centres. However this is not an option... today.

WLCG is therefore a distributed, or grid-based, infrastructure - the most effective solution for meeting the data analysis challenge on this unprecedented scale.

Currently WLCG is made up of more than 170 computing centers in 36 countries to process, analyze and store data produced from the LHC, making it equally available to all partners, regardless of their physical location.

Grid computing

The WLCG is now the world's largest computing grid. It is based on the two main global grids currently in operation, as well as many associated regional and national grids across the world.

See Grid Computing for more about WLCG grid computing, and GridCafé for information on grid computing in general.


The WLCG is composed of four levels, or “Tiers”, which are made up of the computer centres. The tiers are called Tier 0, Tier 1, Tier 2 and Tier 3. These tier sites process, store and analyse all the LHC data between them.


Massive multi-petabyte storage systems and computing clusters with thousands of nodes connected by high-speed networks are the building blocks of the WLCG centres. Find out more in Components.

Data processing

The challenge of analysing the volume of data produced at the LHC is an immense task. Two-stage processing using dedicated algorithms are in continuous development to reduce data 'noise', and assist in focusing on the most important data which could bring new physics discoveries.