Difference between Grid Computing and Utility Computing

1. Grid Computing :
Grid Computing, as name suggests, is a type of computing that combine resources from various administrative domains to achieve common goal. Its main goal to virtualized resources to simply solve problems or issues and apply resources of several computers in network to single problem at same time to solve technical or scientific problem.

2. Utility Computing :
Utility Computing, as name suggests, is a type of computing that provide services and computing resources to customers. It is basically a facility that is being provided to users on their demand and charge them for specific usage. It is similar to cloud computing and therefore requires cloud-like infrastructure. 

Difference between Grid Computing and Utility Computing :

Grid Computing	Utility Computing
It is a process architecture that combines different computing resources from multiple locations to achieve desired and common goal.	It is process architecture that provide on-demand computing resources and infrastructure on basis of pay per use method.
It distributes workload across multiple systems and allow computers to contribute their individual resources to common goal.	It allows organization to allocate and segregate computing resources and infrastructure to various users on basis of their requirements.
It makes better use of existing resources, address rapid fluctuations in customer demands, improve computational capabilities, provide flexibility, etc.	It simply reduces IT costs, easier to manage, provide greater flexibility, compatibility, provide more convenience, etc.
It mainly focuses on sharing computing resources.	It mainly focuses on acquiring computing resources.
It is of three types i.e., computational grid, data grid, and collaborative grid.	It is of two type i.e., Internal and external utility.
It is used in ATMs, back-end infrastructures, marketing research, etc.	It is used in large organizations such as Amazon, Google, etc., where they establish their own utility services for computing storage and applications.
Its main purpose is to integrate usage of computer resources from cooperating partners in form of VO (Virtual Organizations).	Its main purpose is to make computing resources and infrastructure management available to customer as per their need, and charge them for specific usage rather than flat rate.
Its characteristics include resource coordination, transparent access, dependable access, etc.	Its characteristics include scalability, demand pricing, standardized utility computing services, automation, etc.