About RNCalc

RNCalc is a free library of nursing calculators — oral and parenteral dosing, IV flow rates, weight-based dosing, drip rates, and the unit conversions that show up every shift. It's built for working nurses, nursing students, and educators who want a fast, reliable answer without intrusive ads, signups, or paywalls.

A brief history

RNCalc grew out of a long-running family of calculator sites I've maintained for more than two decades. The original calculators were general engineering and physics tools I built for my own use in school. Over time, readers — including nurses and nursing students — started asking for clinical math tools that were easier to trust and easier to use on a phone at the bedside or at a study desk.

RNCalc was created to give the nursing-specific calculations their own focused home, separate from the general-purpose tools. Each calculator is built around the way the calculation is actually used on a real shift or in a real exam — clear inputs, clear units, and a worked example so the math is never a black box.

How the calculators are built and verified

Every calculator on RNCalc is grounded in standard nursing pharmacology and dosage-calculation references — the kind of texts and drug references used in nursing programs and on the floor. Each formula is cross-checked against those sources, the worked example on every page is computed by hand and independently verified, and the calculator's units, defaults, and rounding behavior are reviewed to match how the calculation is normally written up in practice.

Nursing content is safety-critical, and I treat it that way. Reader bug reports — from nurses, students, and instructors who notice a unit mismatch, a rounding edge case, or an assumption that isn't clearly stated — are one of the most valuable forms of review this site gets. If you spot something wrong, please email me. I'd rather fix an error than defend one.

A note on appropriate use

RNCalc is a study and quick-reference tool. It is not a substitute for clinical judgment and is not intended as the sole basis for any patient care decision. Always verify dosing, rates, and units against your institution's policies, the prescribing information for the specific drug and patient, and a second qualified clinician where your protocols require it. Use the calculators on this site as a check, not as the final word.

About the author

Hi, I'm Jimmy Raymond. I built and maintain RNCalc along with a family of related calculator sites. I earned a B.S. in Environmental Engineering from New Mexico Tech and a B.S. in Computer Science from the University of New Mexico — the engineering side gave me the dimensional-analysis and unit-handling discipline that nursing math demands, and the computer science side gave me the tools to turn those calculations into software a nurse or student can use in a few seconds.

My professional work has taken me through safety-critical aerospace and space systems, real-time embedded software, and full-stack web development. I've shipped code to the standards used for aircraft, medical devices, and nuclear systems — contexts where “almost right” isn't right. That discipline is where the calculators on RNCalc get their design philosophy: the formula has to be correct, the units have to work out, the assumptions have to be stated, and the limits of the tool have to be honest.

I'm not a nurse, and RNCalc is not a substitute for one. What I can do is build calculators that get the math right, are easy to use under pressure, and treat the people using them with respect. I'm based in Albuquerque, New Mexico.

Contact

Email me at aj@ajdesigner.com for corrections, calculator requests, or general feedback. You can also find me on LinkedIn.

— Jimmy