RxMedCalc

RxMedCalc is a free, browser-based library of more than 90 clinical calculators, 50 drug-dose references and 35 clinical guides built for emergency and primary care decision support: you pick or search a tool, enter bedside values such as blood pressure, weight, creatinine or gestational dates, and get back a score, risk percentage, dose volume or guideline-based management flag.

What is RxMedCalc?

RxMedCalc is a free medical calculator platform covering emergency and critical care, paediatrics, neonatology, obstetrics, renal, respiratory and general medicine dosing. Its inputs are routine clinical parameters — systolic and diastolic pressure, body weight, serum creatinine in mg/dL or µmol/L, MCV and RBC count, age-in-hours for newborns, LMP or IVF transfer dates — and its outputs are scores, risk percentages, infusion rates and dose volumes. It runs in any browser with no login and no app install, and the site states that no patient data is stored. The tools are described as built by a practising physician and are aligned to WHO, NICE, BTS, RCP, AAP, NRP, SSC, GINA and ACOG consensus guidance.

What makes RxMedCalc stand out?

• Guideline-anchored calculators — Scores follow named consensus sources, including NEWS2 (RCP 2017) with SpO₂ Scale 1 and 2 plus ACVPU, CURB-65 with BTS admission decisions, CURB/NICE D-Dimer pathways for Wells DVT and PE, APACHE II for ICU mortality, and PHQ-9/GAD-7 with the item 9 suicidality alert.
• Rabies PEP Scheduler — Calculates vaccination dates on Days 0, 3, 7 and 28 and the RIG dose by body weight under the WHO 2018 Essen regimen, covering wound categories I to III, with a separate ARV Dose Calculator for HRIG/ERIG and intradermal schedules.
• On-page IV Drip Rate Calculator — Works directly on the homepage, converting volume and time into drops/min and mL/hr using 10, 15, 20 and 60 gtts/mL macro, blood, standard and paediatric micro sets.
• Adaptive BMI classifications — Toggles between global WHO thresholds and Asian/Indian cutoffs (overweight from 23, obese from 25) and adds waist-circumference risk alongside the WHO comparison.
• Renal and dosing support — eGFR via CKD-EPI 2021, Cockcroft-Gault and MDRD with CKD staging G1 to G5 and nephrology referral thresholds; IBW via Devine, Robinson, Miller and Hamwi formulas with adjusted body weight and ARDSNet tidal volume.
• Paediatric and neonatal suite — APGAR at 1, 5 and 10 minutes with NRP 2020 guidance, AAP 2022 phototherapy thresholds for newborns from 35 weeks, paracetamol dosing at 15 mg/kg, ORS rehydration volumes and WHO 0 to 5 year growth Z-scores.
• Obstetric bundle — ObsCalc packs 10 tools including gestational age, Hadlock estimated fetal weight, Bishop score and VBAC eligibility, plus a due date calculator accepting LMP, IVF transfer or ultrasound dating.
• Occupational health tools — Spirometry predicted FEV₁, FVC, FEV₁/FVC and PEFR with obstructive, restrictive and mixed classification, plus a 76-item biomedical waste colour-code search.

Who should use RxMedCalc?

• Emergency physicians and registrars: run CURB-65, qSOFA, NEWS2, GCS, MAP and Wells scores at the bedside to decide admission, escalation and imaging.
• Paediatricians, residents and nurses: calculate APGAR, weight-based paracetamol doses and ORS volumes, and plot growth against WHO percentiles.
• Obstetricians, midwives and family physicians: date pregnancies from LMP, IVF or scan and work through Bishop score, EFW and PPH risk in one suite.
• Pharmacists and prescribing clinicians: use Cockcroft-Gault CrCl and ideal or adjusted body weight to set renal dose adjustments for antibiotics, DOACs and chemotherapy.

What can you do with RxMedCalc?

• Travel and infectious disease clinics: enter body weight and wound category to get the full four-dose rabies PEP schedule and the correct RIG volume.
• Ward and ICU teams: score NEWS2, APACHE II and anion gap with albumin correction, and get escalation thresholds and delta-delta ratios alongside the number.
• Primary care physicians: convert HbA1c between NGSP percent and IFCC mmol/mol, calculate ASCVD 10-year risk with statin recommendations, and stratify AFib stroke risk via CHA₂DS₂-VASc.
• Occupational health assessors: feed spirometry measurements in and get predicted values with defect classification against ATS/ERS-aligned equations. ALso visit our OB Wheel calculator

Pricing

RxMedCalc is free to use. The site states there is no login requirement, no patient data storage and no paid tier; all 90 calculators, drug-dose pages and clinical guides are listed as open to anyone.

FAQ

Is RxMedCalc free?

Yes. Every calculator, drug-dose reference and clinical guide is free, and the homepage lists free access, no login requirement and mobile-friendly use as core features rather than trial limits. There is no paid tier described anywhere on the page.

Does RxMedCalc store patient data?

No patient data is stored. The site states "No Patient Data Stored" and "No Login Required", so calculations run without an account and without submitting identifying information about the patient whose values you enter.

Which guidelines do the calculators follow?

Tools are built against named sources including WHO, NICE, BTS, RCP 2017, ACOG, GINA 2024, AAP 2022, NRP 2020, SSC 2021, ADA, CKD-EPI 2021, KDIGO and ATS/ERS reference equations for spirometry.

Can I rely on RxMedCalc results for patient care?

The site carries an explicit medical disclaimer: the calculators may contain errors and are described as reference-only, and it asks clinicians to reconfirm results with a qualified physician and verify calculations independently before any patient action. Results are intended for informational and educational support, interpreted in the context of the individual patient and local protocols.