The Calculator allows the user to set the lower and upper thresholds at any income level. It refers to the lower income level as the “development threshold” and the higher income level as the “luxury threshold”. These terms are used because they are suggestive of a typical and ethically compelling interpretation, where the lower threshold is chosen to reflect an income level modestly above a global poverty line, and the upper threshold is chosen to reflect an income level above which all income is discretionary, and much of it is spent for consumption well beyond basic comforts.