Calculate by QxMD vs AO Surgery Reference
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Calculate by QxMD
This clinical calculator and decision support tool offers over 200 medical calculators and tools for diagnosis, treatment, and prognosis. It adapts to your practice and provides detailed references, integrating with PubMed and Read by QxMD.
- Over 200 medical calculators
- Clinical decision support tools
- Cardiology, internal medicine, and more
- Knowledge translation from research
- Question Flow technology
- PubMed & Read integration
- SI and Imperial units
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From the developer of 'Read by QxMD', 'The ECG Guide' and 'Pedi STAT' comes 'Calculate', a next-generation clinical calculator and decision support tool, freely available to the medical community. "We recommend medical users try the free Calculate by QxMD first..." -from iMedicalApps review "The best free Medical Calculator apps for the iPhone" 'Calculate' highlights tools which impact clinical practice either by simplifying diagnosis, clarifying treatment options or displaying prognosis. Helping you make decisions, not just calculate numbers... Features • Developed by a collaboration of clinician experts from diverse backgrounds • Point-of-care tools in the areas of cardiology, internal medicine, primary care, nephrology, hematology, hepatology, gastroenterology, emergency medicine, oncology, orthopedics, critical care/ICU, ENT, radiology, rheumatology, mental health, respirology, neurology, pediatrics, infectious disease, neurosurgery, general surgery, vascular surgery, and obstetrics. • Converts recent research publications into practical handheld tools - knowledge translation at its best • Automatically adapts to your clinical practice • Unique ‘Question Flow’ technology gets you answers, fast • Detailed references with PubMed & Read integration • Comprehensive and insightful results • Elegant design and intuitive interface • SI and Imperial units More than 200 unique calculators and decision support tools While too extensive to list them all, here is a small sampling of included content: Guide treatment • Determine cardiovascular risk using ACC/AHA, Framingham, Gupta and VQI Cardiac Risk Index • CHADS2 & CHA2DS2-VASc to guide treatment in atrial fibrillation • Understand bleeding risk in atrial fibrillation using HAS-BLED & OBRI • TIMI risk score in ACS • CIWA in alcohol withdrawal • Rule of 9s & Parkland formula in burns • Water deficit in hypernatremia • Timing of surgery with Aortic Stenosis Risk Score • Risk stratify pneumonia (CURB-65, PORT) • NIH Stroke Scale in acute stroke • Imaging in possible subarachnoid hemorrhage with Ottawa SAH Rule Determine Prognosis • Cirrhosis (MELD, Child-Pugh) • Chronic Kidney Disease (Kidney Failure Risk Equation) • Heart failure • Lymphoma (NCCN-IPI, IPI24, R-IPI) • Myelodysplastic Syndrome (IPSS-R, WPSS) • Myeloma (ISS, R-ISS) • Hemodialysis • COPD (Bode) • Pancreatitis (BISAP, Ranson's) • Cardiac surgery (Euroscore II, Cleveland Clinic, Mehta) • Critical care (APACHE II, SOFA) • Neurologic outcome (DRAGON, CAM-ICU, modified Rankin, FOUR score, Hunt & Hess) Calculate • Ideal body weight, BMI and BSA • Due date and gestational age • Extensive formula used in echocardiography and invasive hemodynamic monitoring • Kt/V in dialysis patients • eGFR with CKD-EPI, MDRD & Schwartz • A-a gradient Classify • Angina (CCS) • Congestive heart failure (NYHA) Screen • Diabetes • Breast cancer Reduce and predict perioperative complications • WHO Surgical Safety Checklist • Predictive models for cardiac surgery, vascular surgery and coronary angiography • Postoperative Respiratory Failure Risk score Manage • Head, neck, ankle and knee injuries (NEXUS, Ottawa ankle/knee, Canadian C-spine and CT head rules) • DVT and PE (PERC, Wells, PESI) • Pulmonary nodules • TIA (ABCD2) Stage • Lung cancer • Renal cell carcinoma • Head & neck cancers Understand • TTKG in hypokalemia and hyperkalemia • Dermatomes Diagnose • Heparin Induced Thrombocytopenia • Infective Endocarditis • ARDS • Autoimmune Hepatitis • Sleep disorder (Epworth Sleepiness Scale) And much, much more... Researchers, contact us to see your research in our app at contact@qxmd.com Founded my medical professionals, QxMD Software is dedicated to creating high quality, point-of-care tools for practicing health care professionals. Recognized as a leading developer of free medical software for mobile devices, QxMD develops content in cooperation with expert physicians from their respective fields.
AO Surgery Reference
Access a comprehensive online repository of surgical knowledge for fracture management. It provides detailed guidance on diagnosis, treatment, and aftercare for numerous fracture types, supported by extensive illustrations and expert review.
- 353 fracture types covered
- 172 surgical approaches
- 1222 surgical procedures
- Over 30,000 illustrations
- Feline, canine, and equine fracture care
- Powerful search function
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QUICK ONLINE REFERENCE IN CLINICAL LIFE Gain easy access to the award-winning AO Surgery Reference. AO Surgery Reference is an online repository for surgical knowledge. It describes the complete surgical management process from diagnosis to aftercare for all fractures of a given anatomical region, and also assembles relevant material that the AO has published before. It gives access to: • aid in surgical decision making for 353 fracture types • 172 approaches • 1222 surgical procedures • all richly illustrated with more than 30'000 Illustrations and much more. To ensure the quality of the content, it is authored, edited, and peer reviewed by experienced AO Faculty from all over the world, some of which are also well-known textbook authors/editors. This is a relaunch of the AO Surgery Reference app utilizing the same responsive user interface that was released February 2020. The highlights are: • Consistent navigational logic and user experience on all screen sizes • Inclusion of feline, canine, and equine fracture care • Combination of Preparation – Approach – Reduction and Fixation – Aftercare into one step called treatment. • Introduction of a powerful search function, allowing simplifications of the user interface as it replaces previous shortcuts.
Screenshots
Verdict
The clearest difference is ads: AO Surgery Reference at none against Calculate by QxMD's shown. AO Surgery Reference also leads on monetization model (free vs free with in-app purchases) and iOS requirement (13.0 vs 16.0). Calculate by QxMD's advantage is rating (4.8 vs 4.4) and ratings volume (5.1K vs 14). On price, review sentiment, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Calculate by QxMD holds the better App Store score, 4.8 against 4.4. That said, the two scores are not equally well evidenced: Calculate by QxMD has 5.1K ratings behind it against 14, so its average is the more settled of the two. Written reviews point the same way: 86% of Calculate by QxMD's written reviews are positive against 82% of AO Surgery Reference's.
Calculate by QxMD ships an update every 6 weeks, AO Surgery Reference every 6 months. The most recent releases landed on September 20, 2026 and September 18, 2026 respectively.
| Parameter | Calculate by QxMD | AO Surgery Reference |
|---|---|---|
| Price | Free | Free |
| Rating | 4.8 (5.1K ratings) — better | 4.4 (14 ratings) |
| Positive reviews | 86.5% of reviews — better | 82.2% of reviews |
| Number of ratings | 5.1K — better | 14 |
| Update frequency | Every 6 weeks — better | Every 6 months |
| Ads | Yes | No — better |
| In-app purchases | No | No |
| Monetization | Free with in-app purchases | Free — better |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 16.0 | 13.0 — better |
| Further details — not scored | ||
| Size | 118 MB | 1 MB |
| Age rating | 17+ | 17+ |
| Developer | WebMD | AO Foundation |
Customer experience
Calculate by QxMD
AO Surgery Reference
Bugs and requests
Calculate by QxMD
Reported bugs
5 issues- App freezes when using multiple calculators
- Unable to add items to favorites list
- Unable to see calculation results after input
- App crashes on startup without internet connection
- Landscape mode not working on iPad
Requested features
5 requests- Dark mode option
- Ability to save/favorite frequently used calculators
- Integration with electronic health records
- Metric to imperial unit conversion
- More specialized calculators (e.g., opioid equivalence, pediatric BP)
AO Surgery Reference
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Calculate by QxMD
No in-app purchases
AO Surgery Reference
No in-app purchases
Questions
Is Calculate by QxMD free?
Is AO Surgery Reference free?
Which has better reviews, Calculate by QxMD or AO Surgery Reference?
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Which is updated more often, Calculate by QxMD or AO Surgery Reference?
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