One run is only the beginning of the bill
You open a zone, start the pump, and let it run for a few hours. The cost of that single run is useful, but it is only one entry in the season's notebook. Repeat the run often enough and even a modest hourly charge becomes a budget decision.
This calculator follows that decision from one event to all planned events, then to the land they serve if you know the area. It uses electricity or fuel consumed while the pump works. The result is an energy or fuel expense, so keep the rest of your irrigation budget beside it rather than assuming it is the whole bill.
How to use the calculator
Start with the pump you actually run
Choose Electricity or Liquid fuel. Enter measured electrical input in kilowatts (kW), or liters of fuel used in one hour (L/h). Enter the price per kWh or liter in your chosen currency. A motor horsepower rating is not the electrical input used on the bill.
Describe one run and the season
Enter pump running hours for one irrigation event and the number of equal-duration events you expect. If you know the area served by this exact schedule, enter it and choose hectares or acres. Leave area empty if you need only event and season costs.
Read the event cost first
Select Calculate pumping cost. The large result is the electricity or fuel cost for one run. Below it, check the hourly rate, season total, energy or fuel used, and optional cost per area. Open the comparison only when you have consumption and price for a second pump that can perform the same job.
Follow a real season through the numbers
Suppose an electric pump draws 3 kW while irrigating. It runs 2.5 hours per event, electricity costs 0.20 per kWh, and the season has 24 events over 1.5 hectares. The event uses 7.5 kWh and costs 1.50 in the entered currency. Those 24 events total 60 pump hours, 180 kWh, and 36.00 for the season. Divide by 1.5 hectares and the energy budget is 24.00 per hectare.
The currency label comes from your entry; the example's 0.20 is arithmetic, not a local tariff recommendation.
The formula behind each result
Start with the unit the pump consumes in an hour. For electricity, input in kW is numerically the kWh used in one hour. For fuel, L/h is liters used in one hour. Multiplying consumption by its unit price gives the running cost per hour.
Cost per hour = consumption per hour × price per kWh or liter
Cost per event = cost per hour × hours per event
Season cost = cost per event × number of events
Season cost per area = season cost ÷ irrigated hectares or acres
The calculator multiplies full-precision values and rounds only what it displays. An area result is meaningful only if the entered area receives the same planned events. If one block is watered twice as often, calculate it separately.
When fuel is the other option
Perhaps there is a fuel pump available as well. A representative 1.2 L/h at 1.30 per liter costs 1.56 per hour. Over the same 2.5-hour event that is 3.90; over 24 events it is 93.60. In this example the fuel charge is 57.60 more than the electric charge over the season.
The second pump must be capable of the required flow and pressure in the same event hours. This calculator repeats the entered hours; it cannot prove the two pumps do equal hydraulic work. If runtimes differ, calculate each pump separately and compare the resulting season costs.
Get the input from a running pump, not a guess
Electrical draw can differ from a motor's rated horsepower. The electricity number here is power drawn while the pump operates at its usual lift, pressure and flow. If a separate meter records 12 kWh during a four-hour run, the average electrical input for this purpose is 12 ÷ 4 = 3 kW. Use a representative run; the pump's power can vary as its operating conditions change.
For a fuel pump, measure consumption under the same working conditions. Five liters used in four hours means 1.25 L/h. A tank-level guess after a very short run is less useful than a careful measurement across enough time to see the difference. Fuel use also changes with engine condition and load.
Use the energy portion of your electricity tariff or the actual fuel price paid. Some electric services also charge for demand or standby capacity. Those charges sit outside this multiplication, as do fuel delivery, oil, repairs, labor and pump replacement. Carry them into a broader farm budget rather than hiding them inside an invented unit price.
If the season refuses to follow the plan
The 24-event example gives 36.00 in electricity charges. If the crop needs 36 events at the same 2.5 hours each, the event cost stays 1.50 but the season becomes 54.00. If the run itself also changes, update its hours rather than assuming the old event cost still applies.
Rain, crop stage, pressure changes and different zones can make a season less tidy than one repeated event. Group runs that share a realistic duration and consumption, calculate each group, then add their season costs. This preserves the simple form while allowing a more honest field budget.
Make the number useful in a field budget
- Check the schedule. If runtime changes with crop stage or weather, calculate a few representative groups of events and add them.
- Check the block. The per-area result assumes the season total serves the area you entered.
- Check the bill. Add fixed utility charges and other operating costs separately.
- Check the water. A low-cost pump still must deliver enough water at the required pressure.
Use the Irrigation Runtime Calculator if you first need hours for a zone. The Farm Pump Flow and Tank Filling Calculator checks water supply against daily demand. Once the pumping expense is known, the Farm Profit Calculator can include it in a larger crop budget.