Dishwasher vs Hand Washing Calculator

Compare a dishwasher load with washing the same amount by hand. Include electricity, hot-water heating, metered water and other per-load costs to see how your habits affect the answer.

How to use Dishwasher vs Hand Washing Calculator

1. Choose the currency used for results. 2. Enter a dishwasher cycle’s kWh and litres. For hand washing, enter the water volume, its temperature rise and the efficiency and fuel price of the hot-water heater. 3. Change a value to update the results, or select Calculate. Review the chart and notes with the total. 4. Use Copy results, Share results or Download result graphic to keep the answer. Shared links include your figures. 5. Reset restores the editable example inputs.

Why use this tool?

A full dishwasher load and a sink of washing-up can be compared fairly only when they clean similar amounts. The cost also depends on how the water is heated and how much goes down the drain. This tool keeps machine electricity separate from the energy used to heat hand-washing water. That matters in a home where the dishwasher uses electricity but the hot-water supply uses gas. The optional per-load costs let you include detergent or another small cost without hiding it in the tariff.

How the calculation works

Dishwasher cost per load = cycle kWh × electricity price + cycle litres ÷ 1,000 × water price + other per-load cost. For hand washing, heating kWh = litres × temperature rise × 4.186 ÷ 3,600 ÷ (efficiency ÷ 100). Multiply this by the hot-water energy price, then add volumetric water and other costs. Annual totals use loads per week × 52. Fixed water and energy charges and appliance purchase costs are excluded. The water-heating calculation assumes 1 kg/L and treats losses through your efficiency input.

Example

For a machine cycle using 1 kWh and 12 litres, with illustrative prices of £0.25/kWh, £3 per 1,000 litres and £0.08 of other costs, the total is £0.366 per load. The hand-washing result changes with its water volume and heating method, so enter those before drawing a conclusion.

Practical tip

Include the same number of plates, pans and utensils in both options. Filling a machine more efficiently can matter as much as a small change in the electricity rate.