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ConvertCalculator is a Dutch calculator form builder company. The company was founded in 2017 by Joris de Ruiter and is based in Rotterdam.

Build beautiful calculators and forms with our easy-to-use calculator builder. Use pre-made templates or create a calculator for your website from scratch!




# Founders


# Employees






Website Rank


Business Started

January 2017

Business Type


Business Idea

online form builder


Productivity Software (Tech)

Company History

Joris de Ruiter details the beginnings of their company in their Starter Story interview: [1]

Q: How did you get started on ConvertCalculator?

I started my first business together with my roommate when I was at university; a creative agency. We started out doing social media and online marketing campaigns. We pivoted to web design when we were one year in. We mostly build simple marketing websites for small businesses, also doing SEO and online marketing.

Besides client projects, I started over 10 projects to get out of the “money for hour” trap. All of them failed.

After building websites for a couple of years, I realized my talent lay mostly in coding more complex web applications. I quit the agency to do web development contract work, all alongside my search for that one project which would take off.

In September 2017 a client approached me and asked if I could build a “calculator” for their website. I thought about all those times entrepreneurs approached me wanting a “price quote calculator” for their website. In nine out of ten cases it was just too expensive to build.

So instead of quoting my client, I suggested they pay $30,- per month for it. They said yes. This was my first validation for the product.

I just listened to Tyler Tringas’ podcast on Indiehackers, which suggested to check Upwork for the demand of a potential product. I did that by searching for “price quote calculator”, and yes, I found several requests for developers to build custom price quote calculators. This was the second validation for the product.

This was enough for me to get an MVP out. I created it in one week, launched my marketing website and showed the calculator to my client. They loved it, but the project was put on hold, so no paying customer yet. You can imagine that this really bummed me out.

I decided to promote ConvertCalculator on Quora and Help forums for website builders.


An example of a Quora comment. Check it out here.

One week later I got my first user ready to start paying. The problem was I didn’t offer a way to upgrade yet. I remember I was at the airport and getting a third email from that customer “complaining” that he couldn’t checkout yet.

I was going on a surf trip and didn’t want to keep him waiting, so I started coding in the plane, pushing the update out when I arrived in Portugal. When I came back from my first surf, I got my first payment confirmation email from Stripe.

That was the validation I needed to keep going!

Source [1]


ConvertCalculator is built on Heroku, React, and MeteorJS.

They use Mailerlite, EmailOctopus, and ContactBubble for their email. Trello and MongoDB Cloud for their productivity.



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