By Riley Kaminer
A few years ago, Oliver Belin noticed something odd. Despite all the talk about digital transformation, many of the world’s largest companies were still relying on Excel spreadsheets to manage supplier payments – arguably one of the most critical levers of business performance.
“Today, most of these analytics are still done manually. There’s no learning. There’s no database. Just PowerPoint decks and Excel files,” Belin told Refresh Miami. That outdated approach to working capital is exactly what he set out to change.
Belin is the CEO of Calculum, a Miami-based startup that helps large corporations optimize supplier payment terms. Put simply: Calculum tells businesses when they should pay their suppliers to stay competitive, boost cash flow, and avoid accidentally funding their rivals.
“If you’re paying a supplier earlier than your competitors, you’re giving them extra liquidity. And they might use that to offer better terms to someone else,” he said. “You’re basically financing your competition without realizing it.”
Calculum started by helping companies act as smarter buyers, benchmarking payment terms, identifying inefficiencies, and generating negotiation scripts to get better deals. But now, the company is flipping the model.
“Every company is both a buyer and a supplier,” Belin explained. “We’re now giving companies the tools to push back when they’re the ones being paid late.” That means helping businesses identify which customers are delaying payments unfairly, arming them with arguments to receive faster payment.
This shift unlocks a much bigger opportunity for Calculum. “We’ve doubled our market by analyzing both sides of the transaction, payables and receivables,” he said.
Behind the scenes, Calculum’s engine is fueled by proprietary data and what Belin calls “lightweight” AI. “We’re not trying to clone your voice or build self-driving cars,” he said with a laugh. “We’re clustering companies based on things like size, location, industry, and then comparing their payment behaviors.”
That data is powerful. Calculum now analyzes over $3 trillion in spend volume and tracks over four million suppliers. It’s growing fast – adding over 100,000 suppliers per month – and aims to hit 7 to 8 million suppliers by the end of the year.
While Belin is quick to downplay the buzz around AI, he’s adamant about the value of proprietary information. “Anyone can build an algorithm. The real edge is sitting on data no one else has,” he said.
Unlike companies that rely on publicly scraped data, Calculum’s insights come directly from clients’ ERP systems. That’s also why the company has stayed away from feeding large language models like ChatGPT. “Once the data’s out there, our business model is gone,” he said.
Calculum’s customer base includes heavy hitters in pharmaceuticals, food and beverage, and enterprise software.
Despite the global footprint, Miami remains Calculum’s base. Belin is all in on the city.
“People in New York don’t really get it, but for me, Miami is the best place to build a startup,” he said. “It’s a hub for events in procurement and finance, there’s a constant flow of investors, and we have access to a massive Spanish-speaking talent pool in the same time zone.”
Most of Calculum’s tech development happens right out of their downtown Miami office, with engineering support from Uruguay, Mexico, Argentina, and Colombia. “About half of our 20-person team is here,” he said. “And we’re aiming for breakeven in the coming months.”
With revenue growing more than 3.5x last year and another 3x expected this year, Calculum is gaining ground quickly. But for Belin, it’s not just about growth metrics. It’s about building something useful, grounded in real data, not hype.
“A lot of people talk about AI. We focus on results,” he said.
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