Blood Pressure Calculator
Enter your blood pressure reading to find out which category it falls into — from normal to hypertensive crisis. This calculator uses internationally recognised categories and includes age-based reference ranges relevant to Australian adults.
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For age-specific context
How It Works
Blood pressure is measured as systolic (top number) over diastolic (bottom number) in mmHg. Categories are: Normal (below 120/80), Elevated (120-129 systolic with diastolic below 80), Stage 1 Hypertension (130-139/80-89), Stage 2 Hypertension (140+/90+), and Hypertensive Crisis (above 180/120). The calculator uses the higher category if systolic and diastolic fall into different ranges.
Quick Reference
| Category | Systolic (mmHg) | Diastolic (mmHg) |
|---|---|---|
| Low (Hypotension) | < 90 | < 60 |
| Normal | < 120 | < 80 |
| Elevated | 120-129 | < 80 |
| Stage 1 Hypertension | 130-139 | 80-89 |
| Stage 2 Hypertension | 140+ | 90+ |
| Hypertensive Crisis | > 180 | > 120 |
| --- | --- | --- |
| Age 18-39 typical | 110-120 | 70-80 |
| Age 40-59 typical | 115-130 | 75-85 |
| Age 60+ typical | 120-140 | 70-80 |
Age-based ranges are averages. Individual targets may vary based on health conditions. Source: Heart Foundation Australia.
Frequently Asked Questions
- What is a normal blood pressure reading?
- A normal blood pressure for adults is below 120/80 mmHg. The first number (systolic) measures pressure when your heart beats, and the second (diastolic) measures pressure between beats. Readings should be taken at rest.
- How often should I check my blood pressure?
- The Heart Foundation recommends all Australian adults have their blood pressure checked at least every two years from age 18. If you have risk factors or a reading above 120/80, check more frequently — your GP can advise on the right interval.
- Does weight loss lower blood pressure?
- Yes. Losing even 5 kg can reduce blood pressure by 5-10 mmHg. The combination of weight loss, reduced sodium intake, regular exercise, and limiting alcohol is often as effective as medication for mild hypertension.
- When should I see a doctor about my blood pressure?
- See a GP if your reading is consistently above 140/90, or immediately if above 180/120 (hypertensive crisis). A single high reading does not mean you have hypertension — your doctor will want multiple readings over time.
How This Is Calculated
- systolic
- = top number — pressure when heart contracts (mmHg)
- diastolic
- = bottom number — pressure between heartbeats (mmHg)
The higher category applies when systolic and diastolic fall in different ranges. A single reading does not diagnose hypertension — your GP will take multiple readings over time.
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Disclaimer
This calculator provides estimates for informational purposes only and should not be considered medical advice. Individual results may vary based on factors not captured by these formulas. Consult a healthcare professional before making changes to your diet or exercise routine, especially if you have any existing health conditions.