If you have eaten, take the measurement at least 2 hours after your meal.
Food adds to your weight and is counted as body composition, which can cause measurement errors.

Urine and stool affect your weight but are not part of your body composition.
They can therefore cause biological errors.

Intense exercise or strenuous movement temporarily changes body composition.

If you stand up right after lying down or sitting for a long time, body fluids move to the lower body, which can slightly affect the measurement.

Heavy sweating temporarily changes body water.

Body water temporarily increases and affects the measurement.

The body is most stable at room temperature; if it is too cold or too hot, body composition changes temporarily.

The longer you stand, the more body water tends to collect in the lower body, and this becomes more noticeable later in the day.