differences in blood pressure readings

What are the reason(s) why my blood pressure is higher in my right arm than my left arm?
Sometimes they are the same. If there is a difference its my right arm that the blood presssure
is higher.

[NTB]

how big a difference do you get?

Anything less than 20/10 would probably not be remarkable. More than that might possibly indicate a problem with the arteries inside.

If they are sometimes the same then that's probably indicating it's just a passing thing.

I can get differences in the SAME arm of 10 points, just from minute to minute sometimes :)

[kenkeith]

Left-arm and right-arm (interarm) blood pressure differences are common. Blood pressure may be slightly higher in your dominant arm. For example, if you're left-handed, your left arm may have a slightly higher reading than your right arm. Several studies have been done to determine what is a ‘normal’ variation between right and left arm. In general, any difference of 10 mm Hg or less is considered normal and not a cause for concern.

The fact that there are differences in right and left arm readings emphasizes the importance of measuring blood pressure in both arms initially to prevent the misdiagnosis of high blood pressure. If one arm has higher blood pressure than the other, that arm should be used to determine if you have hypertension.