Home blood pressure machines are pretty accurate as long as you get a good quality one and not the cheapest one.
The wrist blood pressure monitors that are cheaper are not very accurate like the blood pressure monitors that you put around your arm.
if you get a cheaper blood pressure machine they are not very accurate but if you spend the money and get a quality home blood pressure machine they are the most accurate.
Even the blood pressure machines at doctors offices may not be completely accurate because it's just a machine.
But the blood pressure machines at the doctors office are much more accurate than any of the home blood pressure machines are.
Also make sure you're using the right size of cuff for the blood pressure monitor that fits your arm accurately and make sure the cuff is on correctly and not too loose or too tight.
Stay very still and quite and keep your arm stretched out with your palm of your hand upwards.