Free ECG Viewer Online
Open, view, and analyze Electrocardiogram (ECG/EKG) files instantly. 100% secure, zero-upload client-side processing. Adjust gain, sweep speed, and monitor telemetry safely.
Secure Web-Based Rhythm Player
or click to load sample synthetic rhythm100% HIPAA Compliant Client-Side Rendering. No data leaves your browser.
How to Monitor ECG/EKG Files
Parse signal time-series arrays and render interactive telemetry loops locally in your browser memory without sending patient vitals to any server.
Upload EDF or CSV time-series data into the secure parsing zone.
Set the sweep speed (e.g. 25 mm/s) and vertical gain (10 mm/mV) for standard viewing.
Observe real-time HR, SpO2, and respiratory rates dynamically calculated from the feed.
Zero-Footprint Cardiac Telemetry
Patient privacy is guaranteed. By drawing signal telemetry via HTML5 Canvas requestAnimationFrame loops, the raw ECG data never leaves your device's RAM.
Your sensitive cardiac metrics stay inside your browser. No backend processing, absolute offline compatibility.
Smooth time-series sweeping utilizing hardware-accelerated Canvas 2D API for zero lag.
Accurate 1mm/5mm grid overlay mapping standard ECG paper calibrations.
Diagnostic Lead Geometries & Paper Calibrations
Calibrated time-series parameters standardizing sweep speeds, voltage gains, and electrophysiologic interval timing.
Standard 12-Lead Geometry
Limb Leads (I, II, III) · Augmented (aVR, aVL, aVF) · Precordial (V1–V6)
Maps global cardiac depolarization vectors across frontal and horizontal anatomical planes.
Paper Sweep Velocities
Standard 25 mm/s (0.04s/box) · High-Res 50 mm/s (Tachyarrhythmias) · 12.5 mm/s Trend
Standardized horizontal grid intervals allow accurate heart rate calculation and arrhythmia recognition.
Voltage Gain Sensitivity
Standard 10 mm/mV (0.1 mV/mm) · Half 5 mm/mV (LVH) · Double 20 mm/mV (Low QRS)
Calibrated vertical amplitude grids prevent peak clipping while preserving low-voltage deflection details.
Electrophysiologic Intervals
PR Interval (120–200 ms) · QRS Duration (<120 ms) · QTc Bazett / Fridericia
Precision digital calipers allow sub-millisecond measurement of atrioventricular and ventricular conduction.
Explore Dedicated Clinical Viewers & Calculators
Open and inspect radiologic CT, MRI, and X-ray DICOM (.dcm) files with calibrated window leveling.
Visualize volumetric 3D/4D brain MRI and fMRI data (.nii, .nii.gz) in browser memory.
Inspect high-resolution orthopantomogram (OPG) dental x-rays with zoom and pan.
Calculate estimated Glomerular Filtration Rate using validated clinical creatinine equations.
Frequently Asked Questions
Direct answers to common cardiology questions regarding ECG grid scales, sweep velocities, file formats, and data confidentiality.
What is this Free ECG/EKG Viewer Online?
It is a secure, 100% client-side web application designed to parse, render, and analyze electrocardiogram telemetry files directly in your browser. It features real-time 60FPS waveform sweeping, standard diagnostic paper grids, adjustable gain and sweep speeds, and heart rate telemetry calculations without server uploads.
How does client-side waveform playback work for ECG files?
When an ECG data file is loaded, browser File APIs read signal voltages directly into local memory. The rendering loop uses the HTML5 Canvas 2D context synchronized with requestAnimationFrame to draw continuous diagnostic traces over calibrated 1mm and 5mm grid intervals with zero backend latency.
What are standard ECG paper speeds and calibration gains?
Standard clinical electrocardiography uses a horizontal paper sweep speed of 25 mm/s (where each 1 mm small square equals 0.04 seconds) and a vertical voltage gain of 10 mm/mV (where 1 mm equals 0.1 mV). The viewer allows toggling between 12.5, 25, and 50 mm/s and 5, 10, and 20 mm/mV for specialized rhythm analysis.
Is my patient telemetry and cardiac data secure and HIPAA-compliant?
Yes. The entire telemetry engine executes within your local browser memory sandbox. No cardiac signals, patient names, demographics, or biometric data are ever transmitted to remote servers or stored on external cloud disks, ensuring complete HIPAA and GDPR privacy compliance.
What file formats are supported for electrocardiogram analysis?
The viewer accepts standard biomedical time-series formats including European Data Format (.edf), comma-separated numerical telemetry (.csv), JSON signal streams, and structured clinical XML files. A built-in simulated 12-lead rhythm generator is also provided for immediate verification.
Electrocardiographic Guidelines & Telemetry Standards
Cardiology StandardStandard 12-lead paper speed (25 mm/s), voltage sensitivity (10 mm/mV), and PR/QTc interval calibrations conform to AHA/ACC/HRS recommendations for the standardization and interpretation of the electrocardiogram.
The tools and information provided on this site are for educational purposes only and do not constitute professional medical advice, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions you may have regarding a medical condition.
This page is researched and reviewed by Utilvo's content team against publicly available clinical guidelines and reputable health sources. It is not a substitute for advice from a licensed healthcare provider.