Should you measure blood pressure in both arms?

A clinician may measure blood pressure in both arms during an assessment. Comparing arms can help them decide which arm to use for future readings and whether a difference needs follow-up.

Do not guess what a difference means

Small differences can happen because of cuff placement, arm support, movement, talking or the timing of the readings. A persistent difference is something to discuss with a healthcare professional, not something to diagnose from a home calculator.

If you have been told to use a particular arm, follow that instruction. Otherwise, ask at your next appointment whether both arms should be checked and which arm should be used for your regular log.

If you are asked to compare arms

Use the same monitor, cuff and seated position for both arms. Rest first, keep the arm supported at heart level, and record the arm beside each result. Do not take one reading on each arm while moving between activities and treat them as a precise comparison.

The blood pressure log template includes a notes field where you can record the arm used. You can also read how to measure and record blood pressure at home for the complete setup.

When to ask for help

Ask a healthcare professional or pharmacist to check your technique if the cuff feels wrong, the readings are repeatedly very different, or you are unsure which arm to use. Do not change prescribed medication based on an arm-to-arm difference.

If you feel seriously unwell or believe you may be experiencing a medical emergency, seek urgent local help.

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Sources

• NICE: Hypertension in adults—diagnosis and management
• American Heart Association: Home Blood Pressure Monitoring
• British and Irish Hypertension Society: How to measure blood pressure

Sources last checked 27 September 2026.