Do you have to add a degree when you take your temperature under your arm for an adult? also what is considered a fever?

Temperature: In general a normal temperature is measured at 98.6° orally. If the temp is taken under the arm an addition of 1° is accepted to get the actual temp. A rectal temp is generally 1° higher than the ORAL temperature, so the degree that is measured would be reduced by 1° to get the actual temp. Generally a fever would be an actual temp greater than 100.4 due to the range of normal variation.