Should you build or buy financial calculators for your website?

March 10, 2021

Congratulations, you've decided you want financial calculators on your website to improve the customer experience and enhance the customer journey.

Now the 6-figure question, should you build them in-house or purchase them from a technology partner?

In other words, should you build or buy?

We break down a few factors to consider...

  • Overall Cost
  • Project Scope
  • Time to Value
  • Maintenance
  • Opportunity Cost
  • Roadmap 

Overall Cost

"Why try to reinvent the wheel when there’s already a capability in the marketplace to immediately begin creating value?"

James Robert Lay, Founder and CEO of Digital Growth Institute
A market leader providing digital marketing and sales strategies for financial brands

Build: Building calculators is expensive because it requires so many moving parts. Engineering a highly technical product requires dozens (potentially hundreds) of hours of development, tinkering with complex financial formulas, a deep knowledge and skill set in UX design, and a lot of patience. 

You as the project owner not only spend countless hours organizing the project, but then you need to pay for the design, development, QA, integration, and testing. You need to factor in not only the overall project & development cost, but also your cost as a full-time employee spending countless hours to get this project done.

Buy: The truth is...building complex technology is expensive for whoever builds it. But technology vendors like Chimney are able to gain efficiencies across a wide customer base. By focusing on one products, we're able to offset the expensive engineering, design, and maintenance costs and pass those savings onto customers. 

Project Scope

“Several teams need to collaborate on what the calculator should look and function like”

Michelle Brown, VP Marketing, ZAG Interactive
A full-service digital agency that specializes in helping banks, credit unions and other companies. 

Build: Even though calculators offer simplicity on the surface, they are much more complicated than they seem. In order to build calculators, you have to consider the many potential speed bumps along the way.

Simply put, there are just so many things that can go wrong when building financial calculators:

  • Mobile-first and responsive design
  • ADA & WCAG standards
  • Complex formulas with underlying equations and variables
  • UX/UI design 
  • Compliance requirements
  • Interactive charts and graphs that react in real-time
  • API integration with ever-changing interest rates
  • SEO optimized back-end crawlable and indexable by Google
  • Legal considerations

Your business is likely already outsourcing lots of things to outside experts and vendors, from legal services to accounting software to office cleaning. So why would you attempt to build a complex interactive tool for your website with all these unknown requirements?

Buy: If you want to buy calculators from a vendor, the project workstream takes one person on your team spending a few hours doing online research and taking demos. If you’re working with a proper technology partner, they’ll help you understand the process, compare your options, and customize a solution exactly to fit your needs. 

Time to Value

“There’s a reason why agencies often recommend third parties when they offer a product that can speed time to market and meet consumer expectations”

Michelle Brown, ZAG Interactive

Build: The typical time to design and launch a custom calculator from scratch is 12-16 weeks (that is in addition to the time it takes for you to build the business case and win budget). 

You have to define the scope, build a project plan, work with a UX/UI designer, a developer, your website team, compliance, legal, and your boss, getting approvals at every step. Formulas are complicated and going from QA testing ---> to staging ---> to publishing can be a complicated process. On top of this, legal and compliance mean well, but they create serious roadblocks to getting things up and running.

Buy: Buying calculators will shrink your time to value dramatically - the typical time to launch a custom calculator with Chimney is 24-48 hours after we’ve cleared any necessary vendor onboarding/infosec requirements of course (At Chimney, we are always deemed a low-risk vendor (because we don’t handle any PII or sensitive information).

Before Chimney, I would get emails from customer care and member services saying our calculators weren’t working. So I made it a top priority. I did a lot of research on different calculator companies, but ultimately chose Chimney because I really wanted to invest in something that would help us stand out as a brand in the credit union landscape”

Kassandra Martin, Direct Federal Credit Union


“Once live, the calculator will need to be maintained over time to ensure it continues to function as technology and user experience trends change.

Michelle Brown, Zag Interactive

Build: Change requests are expensive and billable hours add up quickly. Your developers are busy. There are so many competing priorities that we often see calculators go broken for weeks before they’re fixed. If you’re thinking about building calculators in-house, ask yourself if you have confidence that you can get the help you need if you want to make an update or something breaks.   

Buy: 99% uptime guaranteed and updates pushed live automatically each month means you don’t have to worry. Part of what you’re buying with a technology vendor is peace of mind. If you find a technology vendor with high performance standards (like Chimney), you have the confidence of entire support and engineering team dedicated to quickly solving any issues that may arise. 

Opportunity Cost

What’s the opportunity cost in regards to time, energy, effort, and talent when you try to create something from scratch?

James Robert Lay, Digital Growth Institute

Build: In addition to your workload, the web engineering/development team is strapped for time and resources. Every additional ticket and development hour spent on building and fixing financial calculators is time that could be spent on other high impact activities. 

Buy: For digital marketers, expectations are rising while your budgets are decreasing. If you partner with a technology vendor, you are able to get this project off your plate in a fraction of the time so you can move on to other areas.


Build: We know what you’re probably thinking… there’s got to be at least one “pro” in the build column, right? Normally that is something like not having to give up creative control or having a product that’s unique to your brand. The most common reason for building financial calculators in-house is customization and control. However with the right partner, you can retain full control of your calculators and have access to customization tools. 

Buy: With Chimney, the calculators are yours – we just do the heavy lifting for you. We’ve built the industry’s only platform to allow for full control over the branding, the labels, the text, and the buttons. So you can have the best of both worlds. A fully custom calculator that you didn’t have to spend 3 months building on your own. 

In summary: Buy calculators, avoid pain

“Most institutions outsource their financial calculators in order to benefit from some of the key features that users expect – a modern user experience, mobile responsive, ADA conformance, search engine friendly and use of the latest technology.”

Michelle Brown, ZAG Interactive

While there are many factors to consider...the cost, ongoing maintenance, and complexities of interactive tools make financial calculators an ideal candidate to outsource to an expert. 

To recap, here are a few key questions to ask when considering building new financial calculators.

  • Project Scope: How big is this entire project actually going to be?
  • Time to Value: How quickly will we be able to show measurable value?
  • Overall Cost: How much is this project actually going to cost all together?
  • Maintenance: How confident am I in our ability to stay up to date on the functionality of our calculators?
  • Opportunity Cost: What else could we spend our time doing instead of this project?
  • Customization: How much control do we need over the customization?

The bottom line: Leave the complex (and painful) interactive calculator tool-building to the experts so you can focus on your day job.

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