The measurement markings on the S-bottle are not calibrated. The safe margin on every baby bottle allows for a deviation of up to 5%, regardless of your child's age or the amount of formula you are giving.
Example: If you are giving 50 ml of formula, the measurement on the S-bottle may deviate by up to 2.5 ml more or less. If the deviation is greater than 2.5 ml when giving 50 ml, as in this example, we offer a warranty on the bottle.
The cap of the S-bottle does have a calibrated scale. All bottle caps have a measurement marking. If you need to measure formula very precisely, you can use the cap of the S-bottle.