Blood Pressure Calculator
Understand your blood pressure readings and see where they fall in clinical categories.
Blood Pressure Reading
Calculator guide
Blood Pressure Guide
Enter systolic and diastolic readings to view a basic interpretation from the calculator. Blood pressure numbers can vary with measurement conditions, so use the result as a prompt to understand a reading, never as a diagnosis.
How to use the calculator
- 1Measure with a suitable, correctly sized cuff and enter the upper systolic number and lower diastolic number in mmHg.
- 2Submit the values and read the displayed category or note for that result.
- 3If a reading concerns you, repeat it as directed by a health professional and discuss it with a clinician; seek urgent care for severe symptoms.
Important details to understand
1.Start with the right inputs
Check every number, date, unit, and selected mode before calculating. A correct formula can still give a misleading answer when an input is missing, entered in the wrong unit, or based on a different time period.
2.Know what the calculation includes
The method below describes what this tool uses. Real situations can involve extra rules, costs, calendar conventions, or personal details that are not part of the form, so compare the assumptions with your actual question.
3.Read the unit and rounding
Look at the label as well as the displayed number. Rounding can change the last digits, and results in different units or time periods are not directly comparable until you convert them consistently.
4.Treat the result as a useful check
Use the output to understand a calculation, explore a scenario, or make an initial estimate. When a result affects a formal deadline, a health decision, a contract, or a large payment, confirm it with the relevant source or qualified professional.
How the calculation works
Systolic pressure is the pressure during a heartbeat; diastolic pressure is between beats. The page compares the two entered numbers with its programmed category thresholds. It does not account for a person's full medical history, medications, pregnancy, or measurement technique.
A worked example
A reading is written as systolic over diastolic, such as 120/80 mmHg. The two values are evaluated separately by the page's category rules.
When this calculator is useful
Understand the format of a home reading and keep a simple record to discuss with a healthcare professional.
Planning ahead
Try a few realistic input values to see how a change in an amount, measurement, date, or rate affects the answer.
Learning the method
Follow the explanation and example to understand which inputs matter and how they are combined.
Checking your own work
Compare the result with a hand calculation, a worksheet, or a trusted source when you need an independent sense check.
Explaining a result
Keep the original inputs and units with the output so another person can understand what was calculated.
Tips for a more reliable answer
- Enter the values from the same source and keep units consistent throughout the calculation.
- Check that you selected the mode or option that matches the question you are trying to answer.
- Use the worked example to confirm you understand the inputs and the kind of result the tool returns.
- Save the inputs with the result so you can review or repeat the calculation later.
Limitations and assumptions
One reading cannot diagnose high or low blood pressure. Cuff fit, posture, rest, stress, activity, and device accuracy matter. Threshold guidance can vary and should be confirmed with a clinician; symptoms require care regardless of a calculator label.
Every result depends on the information entered and the method described above. The calculator cannot confirm that the inputs are complete or that its assumptions match a particular provider, policy, location, body, or real-world situation.
Frequently asked questions
What do the two values mean?
Systolic is the top number during a heartbeat; diastolic is the bottom number between beats.
Can this diagnose hypertension?
No. Diagnosis requires appropriate measurements and clinical assessment.
Should I ignore symptoms if the result looks normal?
No. Get medical advice for concerning symptoms regardless of this estimate.
Why might my result differ from another calculator?
Tools can use different assumptions, units, date conventions, included costs, or rounding rules. Compare the inputs and method descriptions before deciding that one result is wrong.
What should I check if the answer looks wrong?
Review the selected mode, each entered value, the units, and any optional fields. Then compare a simple example with the method described in this guide.
Can I rely on the result for an official or high-impact decision?
Use the result as an estimate or explanation and check the limitations listed for this tool. Confirm important decisions with the relevant official source or a qualified professional.