A Letter From the Founders: MDCalc Marks 20 Years

Why should life-saving decisions depend on memory alone?

Twenty years ago, that question sat with us on almost every shift. We were exhausted trainees trying to wedge dozens of risk scores into our heads because the alternative was digging through pocket cards, PDFs, or textbooks we didn’t have time to open.

Some things in medicine truly must be memorized: drug doses in a code, or the steps to help a newborn take their first breath. But clinical decision tools were never meant to live in anyone’s head. They were designed to guide judgement, not test recall.

So Graham built a basic website to make his work a little more manageable. It wasn’t a company; it was a coping mechanism. And we had no idea that the problem we were trying to solve - cognitive overload in real-time medicine - was far bigger than our own experience.

After Graham met Joe during residency, the project shifted from a scrappy coping mechanism to something with real ambition. Working together didn’t just add another pair of hands - it gave MDCalc a second brain, a weight and counterweight, and the early sense that this little website might matter to more than the two of them.

The original MDCalc website, created in 2005.

Then came the email that changed everything.

A critical care physician in Australia wrote to us during a night shift. She had two very sick patients and only one ICU bed. One was a man with a pulmonary embolism - with some of his vital signs right on the edge. He looked stable enough - and had been for several hours - but any further decline would require immediate intervention.

She opened MDCalc, calculated his PESI score, and felt confident he was safe to move to the ward. That freed the ICU bed for her other patient: a septic mother who was starting to crump.

Later she wrote, “Your tool helped me make the right decision. It helped me feel safe watching the PE patient on the floor.”

That message made something clear: MDCalc wasn’t just a convenience anymore. It was becoming part of how clinicians reasoned under pressure - giving clarity in moments where uncertainty could change lives.

From there, MDCalc grew the way the best clinical tools do: one clinician sharing it with another. No marketing, no "targeted campaigns," just peer-to-peer trust. Today, more than four out of five US clinicians, across essentially every specialty and every corner of the world, use MDCalc. With nearly 900 evidence-based calculators - each one hand-reviewed by our clinician team - MDCalc has quietly supported more than a billion patient encounters.

We’re proud of that reach, but we’re prouder of the values behind it: safety, simplicity, and trust. Every tool is vetted by practicing clinicians. Every explanation is grounded in evidence. Every feature is designed to support judgment, not replace it.

And we didn’t build it alone. MDCalc has always been shaped by its community - the emergency physician who flagged a new score, the resident who spotted a confusing interface, the surgeon who shared a tool developed by a colleague, the educator who teaches EBM with MDCalc every morning. You’ve improved the platform year after year.

Now, as we reach this milestone, the world around us is shifting again - and the original problem MDCalc set out to solve has only intensified. Clinicians face more information, more tools, and more pressure to make fast, accurate decisions than at any point in history. And for the first time, AI is sitting beside them: powerful, promising, but often untested or opaque. The potential is enormous - so is the risk when technology moves faster than evidence.

What’s striking is how closely this moment echoes our beginning. Two decades ago, we were overwhelmed by information we were expected to memorize. Today, clinicians are overwhelmed by information they’re expected to interpret, validate, and trust instantly.

In many ways, AI is trying to answer the same question that launched MDCalc: How do we get clinicians the right information, at the right moment, with clarity and confidence?

But unlike 20 years ago, we now have tools capable of surfacing evidence in real time. The challenge - and responsibility - is making sure this new speed never comes at the cost of safety or accuracy.

That’s the work ahead for MDCalc’s next chapter.

Our goal is to bring MDCalc’s foundational values into the era of intelligent decision support. AI can help clinicians find tools faster, interpret evidence more precisely, and understand context in ways static resources never could. But these capabilities must be designed around the clinician - never in place of the clinician.

As we enter our third decade, MDCalc is becoming more connected, more intelligent, and more personalized. Over the coming year, you’ll see MDCalc evolve in ways that make discovery and decision support feel truly seamless:

• A redesigned navigation experience that mirrors the way clinicians actually work

• Smarter, AI-powered search that surfaces the right tools quickly - and explains why

• New ways to save, organize, and share the tools and insights you rely on most

• A deeper educational layer that brings expert commentary and clinical dialogue to the surface

• A personalized home screen that adapts to your specialty, your practice, and your patterns

• A new generation of tools and integrations built for speed, precision, and safety

One of the most important initiatives in this evolution is the MDCalc Quality Rating System. As clinical tools and AI-driven models multiply, clinicians deserve a transparent way to understand which tools are supported by strong evidence, aligned with guidelines, and relevant in real-world practice. Developed with an expert advisory board and grounded in clear methodology, the Rating System strengthens MDCalc’s role as a trusted guide in a crowded, fast-changing landscape.

It’s a continuation of MDCalc’s original mission: helping clinicians cut through complexity and find clarity - safely, responsibly, and without noise.

Looking back, there’s a straight line between our founding moment - two trainees trying to make sense of the evidence - and the moment we’re in now, where AI can deliver real-time support but requires principled stewardship. The same question that sparked MDCalc twenty years ago is the one we’re still answering today, just with more powerful tools and a wider lens.

Why should life-saving decisions depend on memory alone? They shouldn’t.

Clinicians deserve tools that are fast, transparent, rigorously vetted, and shaped by the realities of clinical practice. They deserve technology that amplifies evidence and strengthens judgment. They deserve partners who understand the stakes.

For twenty years, MDCalc has been proud to be that partner. And as we step into the next twenty, we’re building with the same intention and the same responsibility that guided us from the start: when evidence is accessible, clinicians practice at their best - and patients receive better care.

To every clinician who has trusted MDCalc, taught with it, challenged it, or improved it: thank you. MDCalc is what it is because of you.

Here’s to the next chapter - one where evidence, technology, and clinical judgment work more seamlessly together than ever before.

With gratitude,

Graham & Joe