How a Team of IT Architects came to Build an Excel Calculation Engine

IT Architects and Excel Don't Mix. (Or Do They?)

As Software IT Architects, we promoted a belief that Excel is evil and that spreadsheets should be banished from the face of enterprise software applications (which, after all, was our world).

Any IT Architect who embraced Excel would be excommunicated and shunned by their peers.

It had somehow become a divine goal, a raison d'être, of the IT Architecture community to eliminate spreadsheets from within the organisations; converting them to database-driven applications where possible.

Eliminating Spreadsheets Totally May Not be Possible

More than 15 years ago however, we had encountered a unique situation whereby converting a spreadsheet into a database application was not going to be easy.

There was one particular spreadsheet; an Excel-based, transport rate calculator that had a lot of clever IT folk stumped.

The spreadsheet was actively being used by the business because it worked!

They were able to produce accurate car transport quotes for their their business and with annual revenues exceeding $20 million.


A few of our peers proposed to redevelop the spreadsheet into a complete ERP system by encapsulating the spreadsheet's rules.

The spreadsheet was unravelled, rate calculations decoded and rules formulated in ways that would better fit a relational database model upon which the new system would be built.

They placed a multi-million dollar price tag on delivering the final solution.

The trouble was, even with that enormous price tag, the project did not proceed for 3 main reasons:

  1. The proposed cost (after factoring risk) would be more than 25% of annual revenues
  2. The same execution of rating logic to the business could not be guaranteed;
  3. The IT department would need to be intimately involved in pricing decisions to ensure the new system would accommodate such decisions.

Moreover, IT licensing and operational costs would go from hundreds of dollars per year, to hundreds-of-thousands of dollars.

There’s a place for Excel spreadsheets and cloud services – empowering businesses of all shapes and sizes to directly create and maintain a new suite of online solutions.

Disrupting a $5m ERP Project with an Excel Spreadsheet

Businesses often find themselves disrupted by the introduction of new technology but on this occasion, instead of proceeding with the redevelopment of the spreadsheet into software, that company chose to continue with it's use.

And, in the process it, unknowingly, also chose to become a disruptor.

Eight years later, in 2013, more evolved and more mature as a consequence of our own experience, we began recognising that Excel provides a real and unique value proposition to businesses.

The Same Excel Challenge but a Different Set of Eyes

As a result, we revisited that same spreadsheet with a different set of eyes, asking a different set of questions.

  • What if, instead of replacing the spreadsheet, we found a way to make it enterprise-grade?
  • Would it be possible to apply a growth hack and SaaS mindset and actually adopt the spreadsheet as the Source System of Record (SSoR) for rate calculation information and run it in a secure and infinitely scalable way?
  • And if we succeeded at doing this, could we be seeing a future of spreadsheet-driven lead generation and conversion rate optimisation?

At the time, our Client was using the spreadsheet to create approximately 30 quotes per day. Each quote involved a series of manual steps and would take 7-8 minutes to complete.

We developed and built the first iteration of a calculation engine to run that same spreadsheet and made it securely available to a private community of our Client's customers.

Fast-forward 3 years (to 2016) and our Client has been able to leverage Calc123 and build their business to a capacity of more than 50,000 quote calculations per month with average calculation time of less than 200 milliseconds.

Calc123 Component Features

The Calc123 platform was designed to run in the cloud taking advantage of the scaling, distribution and high availability features.

Each server within Calc123 platform is complimented with at least one other server performing the same role. The platform can therefore tolerate the addition and removal of servers without disruption.

Cloud-based Quoting Calculators

Online calculators are being increasingly used as engagement tools to provide indicative quotations where customers will "call to order" instead of "calling for a quote".

By using online calculators, you allow your business reduce the number of “time wasters” that may call and instead, focus on attracting serious, potential customers.

Calc123 is the ideal platform to host online calculators for as many web pages as required.

Simply create your calculations in a Microsoft Excel spreadsheet and load into Calc123. A set of preconfigured web services automatically receive the details entered by visitors to your website and perform the necessary calculations.

The resulting web service API can be accessed by many website including those of your partner or affiliate.

Calculation Engine

Configuration Store

Web Services

Management Console

Website Form