Shock Index Calculator
HR ÷ SBP — the early haemorrhage flag that moves before blood pressure does.
Young patients defend their blood pressure until ~30% volume loss — pulse creeping above systolic-derived expectations (SI ≥0.9) flags trouble while the vitals still look 'normal' individually, which is why trauma and obstetric early-warning systems adopted it. It's a trend instrument: a rising index across two readings says more than any single value.
Formula
Reference aid for healthcare professionals only. Every result must be independently verified before clinical use. Never use this tool for self-medication or to replace clinical judgement.
HR ÷ SBP — the early haemorrhage flag that moves before blood pressure does. The Shock Index Calculator is a free, private shock index tool — every result computes instantly in your browser with no sign-up and no data upload.
About Shock Index Calculator
Young patients defend their blood pressure until ~30% volume loss — pulse creeping above systolic-derived expectations (SI ≥0.9) flags trouble while the vitals still look 'normal' individually, which is why trauma and obstetric early-warning systems adopted it. It applies SI = heart rate ÷ systolic BP (normal 0.5–0.7). Use the Shock Index Calculator to get an instant, clearly-explained result with the working shown step by step — free, private and with the source method cited.
How to use Shock Index Calculator
- 1Enter your details in the Shock Index Calculator input fields above.
- 2The result updates instantly with the working and reference bands shown.
- 3Adjust any value to explore how it changes the outcome — it's free and unlimited.
Why use Shock Index Calculator?
- ✓Instant shock index result that recomputes as you type — no waiting, no page reloads
- ✓100% client-side: your health data never leaves your browser
- ✓Shows the actual formula and your numbers substituted in, so you can see exactly how the result is reached
- ✓Based on published, citable sources (Allgöwer M & Burri C 1967; Mutschler M et al., Crit Care 2013 — SI validation)
- ✓Free forever with no sign-up, account or app install
Frequently asked questions
How does the Shock Index Calculator work?+
Young patients defend their blood pressure until ~30% volume loss — pulse creeping above systolic-derived expectations (SI ≥0.9) flags trouble while the vitals still look 'normal' individually, which is why trauma and obstetric early-warning systems adopted it. The calculation uses the formula: SI = heart rate ÷ systolic BP (normal 0.5–0.7). Everything runs instantly in your browser as you type — your inputs are never uploaded.
Is the Shock Index Calculator accurate, and what is it based on?+
The method is traceable to authoritative sources: Allgöwer M & Burri C 1967; Mutschler M et al., Crit Care 2013 — SI validation. Results are estimates — individual variation always applies, so treat the output as a well-grounded starting point.
Is the Shock Index Calculator free and private?+
Yes. It's completely free with no sign-up, and all computation happens locally in your browser, so none of your health data ever leaves your device.
Can I use this for medical decisions?+
This is a reference aid for healthcare professionals and must be independently verified. It is not for self-diagnosis or self-medication.
What can I use the Shock Index Calculator for?+
It's commonly used for shock index, hr over sbp, trauma triage. HR ÷ SBP — the early haemorrhage flag that moves before blood pressure does.
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