Blood Pressure Category Checker

📖 Overview

Enter your systolic and diastolic blood pressure readings to get your category and recommended next steps.

🧪 Example Scenarios

Use these default and higher-pressure example inputs to explore how sensitive this calculator is before using your real numbers.

Input	Base Case	Higher Pressure Case
Systolic (mmHg)	0	0
Diastolic (mmHg)	120	138

⚙️ How It Works

Classifies a blood pressure reading into one of five American Heart Association (AHA) categories based on systolic (upper) and diastolic (lower) values in mmHg.

The Formula

Category = f(Systolic mmHg, Diastolic mmHg) per AHA 2017 guidelines

Systolic	Pressure when the heart beats (upper number)
Diastolic	Pressure when the heart rests between beats (lower number)
mmHg	Millimetres of mercury — the standard unit for blood pressure

💡This calculator is scenario-based. Better input quality leads to better decision quality.

⚠️A reading above 180/120 mmHg is a hypertensive crisis. Seek emergency medical care immediately if accompanied by symptoms like chest pain, shortness of breath, or vision changes.

Quick Reference

Category	Systolic		Diastolic
Normal	< 120	and	< 80
Elevated	120–129	and	< 80
High BP Stage 1	130–139	or	80–89
High BP Stage 2	≥ 140	or	≥ 90
Hypertensive Crisis	> 180	and/or	> 120

When To Use This

Use this tool when you need a fast decision during active planning or execution.
Use this before committing money, time, or tradeoffs that are hard to reverse.
Use this to compare options using the same assumptions across scenarios.

Edge Cases To Watch

Results can be misleading if key inputs are missing, stale, or unrealistic.
Very small or very large values may amplify rounding effects and interpretation risk.
If assumptions change mid-decision, recalculate before acting.

Practical Tips

💡 Measure blood pressure after 5 minutes of rest, seated with feet flat on the floor.

💡 Avoid caffeine, exercise, and smoking for 30 minutes before measuring.

💡 Take two readings 1–2 minutes apart and average them for greater accuracy.

💡 White coat hypertension (high readings only at the clinic) is common — home monitoring gives a truer picture.

Frequently Asked Questions

❓ Which number matters more, systolic or diastolic?

Both matter. A reading is classified by whichever value places it in the higher category.

❓ Can blood pressure vary through the day?

Yes. It is typically lowest in the morning and rises through the day. Stress, caffeine, and activity all cause temporary spikes.

❓ At what point should I see a doctor?

Stage 1 hypertension (130/80) warrants a conversation with your doctor. Stage 2 (140/90) requires medical evaluation and likely treatment.