Heart Rate Calculator
Calculate heart rate from ECG using RR interval, 300/1500 rule, or 6-second method
Calculate Heart Rate from ECG
Medical Disclaimer
This calculator is for educational purposes only. Not suitable for irregular rhythms or arrhythmias. Always consult healthcare professionals for medical decisions.
Distance between two consecutive R wave peaks
Expected RR Interval Calculator
Enter expected heart rate to calculate the corresponding RR interval
Calculation Methods Explained
1. RR Interval Method (Most Accurate)
Formula: Heart Rate = 60 / (RR interval in seconds)
Measure the distance between two consecutive R wave peaks. Convert to time using paper speed, then calculate beats per minute. Most precise for regular rhythms.
2. 300/1500 Rule (Quick Estimation)
Formulas: HR = 300 / (big boxes) or HR = 1500 / (small boxes)
Quick bedside calculation. Count boxes between R waves and divide into 300 (big boxes) or 1500 (small boxes). Less accurate but fast.
3. 6-Second Method (For Irregular Rhythms)
Formula: Heart Rate = (R waves in 6 seconds) × 10
Count R waves in a 6-second strip (30 big boxes at 25mm/s) and multiply by 10. Best for atrial fibrillation and other irregular rhythms.
Normal Heart Rate Ranges
Bradycardia
< 60 BPM
Normal (Adults)
60-100 BPM
Tachycardia
100-150 BPM
Severe Tachycardia
> 150 BPM
ECG Paper Basics
Small Box
1mm × 1mm (0.04 seconds)
Big Box
5mm × 5mm (0.20 seconds)
Standard Speed
25 mm/second
6-Second Strip
30 big boxes long
Clinical Tips
Always check rhythm regularity first
Use 6-second method for irregular rhythms
RR interval method most accurate
300 rule good for quick estimates
Consider clinical context always
Understanding ECG Heart Rate Calculation
What is Heart Rate?
Heart rate is the number of heartbeats per minute (BPM). On an ECG, each heartbeat is represented by a series of waves, with the R wave being the most prominent peak in the QRS complex.
When to Use Each Method?
- •RR Interval: Regular rhythms, most accurate
- •300/1500 Rule: Quick bedside calculations
- •6-Second Method: Atrial fibrillation, irregular rhythms
Important Considerations
Arrhythmias: Irregular rhythms require the 6-second method as RR intervals vary between beats.
Paper Speed: Always verify ECG paper speed. Standard is 25mm/s, but some use 50mm/s which affects calculations.
Clinical Context: Always correlate calculated heart rate with patient's clinical condition and symptoms.
Age-Specific Normal Ranges
Newborns: 100-160 BPM
Children (1-10 years): 70-120 BPM
Adults: 60-100 BPM
Athletes: 40-60 BPM (training effect)
Related Cardiovascular Calculators
Medical Disclaimer
This Heart Rate Calculator is for educational and informational purposes only. It should not be used as a substitute for professional medical advice, diagnosis, or treatment. The calculator is not suitable for patients with irregular heart rhythms or arrhythmias. ECG interpretation requires clinical expertise and should always be performed by qualified healthcare professionals. Always consult with a healthcare provider for proper ECG interpretation and clinical correlation. In case of chest pain, palpitations, or other cardiac symptoms, seek immediate medical attention.