BBC Budget calculator – how Cloud scales to meet demand.


As the Chancellor sits down, his red briefcase closed for another year, millions of people wonder how this Budget will affect them. And they turn to the BBC to find out.

This means that each year, their Budget calculator experiences a major peak in traffic. The application was expected to have exceedingly high traffic volume and see massive spikes, with more than 10 million people visiting during the 48 hour period following the Chancellor’s announcement.

The BBC Budget calculator is a classic Cloud use case. Because Cloud is elastic (it scales easily) the application can deal with extreme peaks of interest and then revert back to normal. To be able to deal with the peak in traffic, upwards of 30 million page loads, physical infrastructure costs would be prohibitively high, have a high initial expenditure required, and this infrastructure would likely be underutilised for most of the year. Using Cloud in this scenario is therefore cost effective, as you pay as you go based on the amount of capacity you use. Cloud enables optimal infrastructure investment, keeping costs low.

But does it live up to expectations? Deloitte Cloud experts set up the BBC Budget calculator on AWS, using a service called Elastic Beanstalk – which helps to deploy and scale web applications and services, handling capacity provisioning, load balancing and application health monitoring. Knowing that the Budget calculator would be within the top featured news stories on the core BBC News website, we needed to make sure it performed. The calculator scales up to 20 virtual servers when needed, while scaling down this number again to reduce cost in non-peak periods and outside of Budget announcements. The Budget calculator has suffered no downtime or errors, even at the highest peaks of traffic. It has also proven to give the best user experience, as well as being consistently available, it has also had an extremely quick average server response of 2 milliseconds per user request.

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