How do I calculate how much it costs to run my pool pump?

Take your pump’s wattage, multiply by hours run, multiply by your electricity rate. Find the wattage on the pump’s nameplate or in the manual. A typical 1.5 HP pump pulls around 1500 watts. Divide by 1000 to get kilowatts (1.5 kW), multiply by hours run, then multiply by your local rate per kWh. For example, 1.5 kW × 1 hour × $0.12/kWh = $0.18 per hour. This assumes full speed — a variable speed pump at low speed might use 300 watts, dropping the cost to about $0.036 per hour.