Step pricing calculation (calculate electricity fee).

Ladder electricity pricing is a method of calculating electricity consumption charges based on a tiered pricing structure. The more electricity you use, the higher the rate you will be charged. Depending on the pricing plan, the first tier may cover a low usage amount at a lower rate, and as you use more electricity, the price per kilowatt-hour will increase in subsequent tiers. This encourages consumers to conserve electricity and avoid high usage charges. The total electricity bill will be calculated by multiplying the number of kilowatt-hours used in each tier by the corresponding rate and adding them up.