• HAS-BLED Score Calculator
    Calculate the HAS-BLED score to estimate 1-year major bleeding risk in atrial fibrillation patients on anticoagulation. Score range 0–9 with risk category.
  • CHA₂DS₂-VASc Score Calculator
    Calculate the CHA2DS2-VASc score to estimate annual stroke risk in patients with non-valvular atrial fibrillation and guide anticoagulation decisions.
  • Ankle-Brachial Index (ABI) Calculator
    Calculate the Ankle-Brachial Index (ABI) from ankle and arm systolic blood pressures to screen for peripheral artery disease (PAD).
  • Metabolic Syndrome Calculator
    Check the 5 NCEP ATP III metabolic syndrome criteria (waist, triglycerides, HDL, blood pressure, glucose). 3 or more met indicates metabolic syndrome.
  • INR Calculator
    Calculate the International Normalized Ratio (INR) from patient PT, mean normal PT, and the ISI value using the standard WHO formula.
  • Aortic Valve Area Calculator
    Calculate aortic valve area (AVA) with the continuity equation from LVOT diameter, LVOT VTI and aortic valve VTI. Free echocardiography tool.
  • Arterial (Vascular) Age Calculator
    Estimate your arterial (vascular) age from carotid-femoral pulse wave velocity (PWV). Educational tool: Vascular Age = (PWV − intercept) / slope.
  • Comfortable Exercise Heart Rate Calculator
    Find your comfortable exercise heart rate from your age using the simple 138 - age/2 rule. A light-intensity target for healthy, sweat-but-not-breathless workouts.
  • Anaerobic Threshold Calculator
    Estimate your anaerobic threshold (AT) heart rate from age and intensity percentage. Uses AT_HR = % × (220 − age) for training zone targeting.
  • Albumin Globulin Ratio Calculator
    Calculate your albumin/globulin (A/G) ratio from albumin and total protein blood test values. Free A/G ratio calculator with worked example.
  • Shock Index Calculator
    Calculate the Shock Index (heart rate divided by systolic blood pressure) to help assess hemodynamic status and shock risk. Free, instant.
  • Qp/Qs Ratio Calculator
    Calculate the Qp/Qs ratio (pulmonary-to-systemic blood flow) from O₂ saturations to quantify left-to-right or right-to-left cardiac shunts.
  • PF Ratio (PaO2/FiO2) Calculator
    Calculate the PaO2/FiO2 (P/F) ratio for oxygenation assessment and ARDS severity grading using the Berlin definition. Enter PaO2 and FiO2.
  • Oxygenation Index Calculator
    Calculate the Oxygenation Index (OI) from FiO₂, mean airway pressure, and PaO₂ to assess severity of hypoxemic respiratory failure.
  • Target Heart Rate Calculator (Karvonen Method)
    Calculate your ideal exercise target heart rate with the Karvonen (heart-rate reserve) method using age, resting heart rate, and intensity.
  • PISA Flow Rate Calculator
    Calculate the PISA (Proximal Isovelocity Surface Area) flow rate from the radius and aliasing velocity using Flow = 2·π·r²·V.
  • Mitral Valve Area Calculator (Pressure Half-Time)
    Estimate mitral valve area from the Doppler pressure half-time using the MVA = 220 / PHT formula. Fast, free echocardiography tool.
  • ICH Volume Calculator (ABC/2)
    Estimate intracerebral hemorrhage (ICH) volume with the ABC/2 method. Enter the three hemorrhage dimensions in cm to get volume in mL.
  • Gorlin Formula Calculator
    Estimate aortic or mitral valve area with the Gorlin formula from cardiac output, heart rate, ejection period, and mean pressure gradient.
  • Doppler Echo Cardiac Output Calculator
    Calculate cardiac output and stroke volume from echocardiographic LVOT diameter, VTI, and heart rate using the standard Doppler velocity-time integral method.
  • EROA Mitral Regurgitation Calculator (PISA)
    Calculate the effective regurgitant orifice area (EROA) for mitral regurgitation using the PISA method from radius, aliasing velocity, and peak MR velocity.
  • ECG Heart Rate Calculator
    Estimate heart rate from an ECG strip using the 300 rule (large boxes) or 1500 rule (small boxes) between R waves. Fast, accurate bpm calculation.
  • Cerebral Perfusion Pressure Calculator
    Calculate cerebral perfusion pressure (CPP) from systolic, diastolic blood pressure and intracranial pressure using CPP = MAP - ICP.
  • Cardiac Output Calculator
    Calculate cardiac output from stroke volume and heart rate. Enter mL/beat and bpm to get cardiac output in L/min instantly with this free tool.