Heart rate often rises before blood pressure falls, so their ratio picks up early warning signs.
How to use the Shock Index Calculator
- Heart rate
- Systolic blood pressure
Results update as you type, and every field accepts the units shown in its menu.
How it works
Divide the pulse in beats per minute by systolic pressure in mmHg.
Inputs explained
| Field | What to enter |
|---|---|
| Heart rate | In bpm |
| Systolic blood pressure | In mmHg |
Example values
How the main result changes when Heart rate changes and everything else stays at the example values above:
| Heart rate (bpm) | Shock index |
|---|---|
| 47.5 | 0.43 |
| 71.25 | 0.65 |
| 95 | 0.86 |
| 118.75 | 1.08 |
| 142.5 | 1.3 |
| 190 | 1.73 |
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
Shock index = heart rate ÷ systolic blood pressureWorked example
Inputs — Heart rate: 95 bpm; Systolic blood pressure: 110 mmHg.
Results — Shock index = 0.86.
Frequently asked questions
What is normal?
About 0.5–0.7 in healthy adults.
Is it used for children?
Age-adjusted versions exist because normal heart rates differ in children.
What formula does the Shock Index Calculator use?
Shock index = heart rate ÷ systolic blood pressure.