One of the assumptions of ordinal utility in consumer behaviour is that

The assumption of ordinal utility in consumer behavior is that utility can only be ranked, meaning that consumers can determine which option they prefer, but they cannot measure how much utility they get from each option or compare the magnitude of utility between different options. In other words, consumers can only say which option is more preferred than the other but cannot precisely quantify the extent of the preference. For example, a consumer may prefer a cup of coffee over a cup of tea, but they cannot precisely measure the difference in the level of satisfaction they derive from each option. This assumption is important because it forms the basis of the concept of indifference curves, which are used to represent consumer preferences in economic models.