How do I calculate a percentage error?

This is for physics-I measured the centripetal acceleration of an object using an accelerometer and also calculated the centripetal acceleration of that same object with equations. My teacher wants me to find the percentage error, but how do I find it? I know the equation, but what is the "actual" and what is the "estimate" value?



Thanks!How do I calculate a percentage error?
actual and estimated are not very good words, you should use observed (the results of your experiments) with predicted (the result of the calculation)



percent error is then [(observed-predicted)/predicted]x100%



so if you observed a value of 3.2 in some units, and predicted a value of 3, your percent error is



(3.2-3)/3 x 100%=6.67%