Robot mower running cost calculator

Enter energy used during a representative mowing week, or the whole mowing season, and your electricity unit rate. Add blades and other recurring costs. The result is a budget for the figures you supply, not a typical mower cost or a savings forecast.

Choose a useful energy figure

Use energy in kWh from a suitable measurement at the socket, or a manufacturer figure with its conditions attached. A charger's maximum power in watts does not tell you how much energy the mower uses over a season.

A weekly reading is scaled by the number of mowing weeks you enter. That assumes the same weekly use throughout the season, even though growth, weather and the work needed may change. A whole-season reading avoids that particular extrapolation.

Use the full electricity unit rate shown on your bill for the time the mower charges. If charging spans several rates, use a consumption-weighted rate or calculate the periods separately.

How the budget is calculated

• Season energy: weekly kWh × mowing weeks, or your whole-season kWh directly.
• Electricity: season kWh × unit rate in pence per kWh ÷ 100.
• Blades: price per replacement set × sets used per year.
• Annual budget: electricity + blades + other annual costs you enter.

Keep the energy figure and unit rate unrounded until the final calculation. Results are shown to the nearest penny; the input evidence may support a less precise budget.

What is left out?

Charging losses and standby use are included only to the extent that your energy figure captures them. A battery capacity figure is not a socket measurement. Include any out-of-season standby cost in other annual costs if it is missing from the energy figure.

Purchase, installation and finance are outside this running-cost budget. A future replacement battery and repairs are also excluded unless you add an annual allowance under other costs. Add servicing, connectivity or software charges there if they apply. Do not count a cost twice.

What if I don't know the energy use?

Leave the estimate unfinished. Ask the manufacturer what its consumption figure assumes about lawn area and operating hours, or collect a suitable measurement. The calculator does not supply a guessed consumption figure.

Are the example prices current tariffs or mower specifications?

No. The worked example uses made-up inputs to demonstrate the arithmetic. Replace them with your own evidence; they are not a quote, recommendation or a measured mower result.