Hourly to seasonal AC costs
See what one operating hour, one cooling day, a 30-day month and your full season add to energy charges.
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AC electricity cost calculator.
Know your cooling budget.
AC running cost equals input watts ÷ 1,000 × average load × operating hours × electricity price per kWh. For example, a 1,200-watt unit at 75% load, used 8 hours daily at $0.27/kWh, costs $58.32 per 30-day month. Enter your own figures below to estimate hourly, daily and seasonal costs.
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For window, portable, mini-split and central AC. Default values are an illustrative starting point; edit them before budgeting.
Current 30-day estimate$58.32
Calculate air conditioner running costs
Watts, hours and rate.
Watts, hours and rate.
Your monthly AC cost.
Results update as you edit. Monthly cost assumes 30 identical cooling days; seasonal cost uses your chosen number of days.
Instant estimate
Your cooling budget
Based on your entered assumptions. AC energy charges only.
Estimated cost per 30-day month
$58.32
216.00 kWh per month
Per operating hour$0.24
Per cooling day$1.94
Full cooling season$233.28
Season energy use864.00 kWh
Running the AC 1 hour less per day would save about $29.16 over this cooling season.
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What you get
Make your AC electricity use easier to budget.
Separate energy use in kWh from the price you pay, then compare changes using the same assumptions.
Runtime and load comparisons
Compare one hour less per day with a 10% relative reduction in average load. These are arithmetic scenarios, not guaranteed savings.
A spreadsheet-ready record
Keep input watts, tariff, energy use and scenario costs in one CSV. Download a separate file for each AC you compare.
How to use the calculator
From AC rating label to a usable cost estimate.
Find input power in watts
Check the label or manual for electrical input. Set average load to reflect cycling during your entered runtime, or use measured average watts with 100% load.
Enter hours and price per kWh
Use your expected daily cooling hours and your own electricity tariff. Enter cents as currency units: 27 cents is 0.27 dollars.
Compare, then download
Review monthly cost and seasonal scenarios. Export the CSV, change the wattage or runtime, and save another estimate for comparison.
Practical savings guide
Compare AC runtime before changing your routine.
These figures follow your current inputs. Weather, humidity, insulation, thermostat settings and equipment behavior can change actual consumption.
Three seasonal scenarios in your CSV
The lower-load scenario uses 90% of your entered average load: 75% becomes 67.5%, rather than 65%. The runtime scenario removes up to one hour daily, without going below zero.
Compare feasible changes while keeping your comfort needs in mind. A 10% load reduction is an assumption, not a prediction for a particular thermostat adjustment.
| Scenario | Season estimate |
|---|---|
| Current settings | $233.28 |
| 1 hour less each day | $204.12 −$29.16 |
| 10% lower average load | $209.95 −$23.33 |
AC electricity cost formula: watts to kWh to cost
Energy (kWh) = input watts ÷ 1,000 × (average load % ÷ 100) × hours
Cost = energy (kWh) × electricity price per kWh
For a monthly estimate, multiply daily energy and cost by 30. For a seasonal estimate, multiply by your cooling days. The hourly result means one operating hour at the selected average load; it is not a full-day average.
If you already know energy use from a suitable meter, multiply measured kWh by the applicable rate directly. Avoid applying a load factor again to measured energy. This tool assumes the same daily runtime and average load throughout the selected period.
How much does a 1,200-watt air conditioner cost to run?
Using 75% average load and $0.27/kWh: 1,200 ÷ 1,000 × 0.75 = 0.9 kW average input. Eight hours uses 7.2 kWh; multiplying by $0.27 gives $1.944 daily and $58.32 for 30 days.
| Runtime / day | Average load | kWh / day | Daily cost | 30-day cost |
|---|---|---|---|---|
| 4 hours | 75% | 3.60 | $0.97 | $29.16 |
| 8 hours | 75% | 7.20 | $1.94 | $58.32 |
| 12 hours | 75% | 10.80 | $2.92 | $87.48 |
| 24 hours | 75% | 21.60 | $5.83 | $174.96 |
| 8 hours | 100% | 9.60 | $2.59 | $77.76 |
Illustrative calculations, not measured equipment performance or an average electricity tariff. Costs are rounded for display; monthly figures use unrounded daily values. This table stays fixed so you can check the formula; the calculator above uses your own inputs.
Calculate with my wattage and tariffFind AC input watts, average load and electricity price
Input watts: use “input power,” “power consumption” or a matching electrical specification from your unit’s label or manual. Cooling capacity in BTU/h, kW of cooling or tons is a different quantity. Include the indoor fan or blower if its consumption is separate from the figure you enter.
Average load: this accounts for power varying within your entered runtime. If eight hours means eight hours switched on, include cycling in the load assumption. If you enter only compressor-on hours, avoid applying the same cycling reduction again. The 75% default is not a recommendation for every AC.
Electricity price: enter your marginal energy price per kWh, including applicable per-kWh charges you want to model. Dividing the entire bill by kWh may include fixed fees and distort the incremental cost of using AC.
Window AC, portable AC, mini-split or central AC: what changes?
The calculation is the same for each type; input power, cycling and runtime differ. Compare units using the same currency, tariff and planning period. Equal watts do not imply equal cooling output, and a lower running cost does not by itself show that a unit can cool the same space.
Why your AC estimate may differ from your bill
Outdoor temperature, room heat gain, humidity, thermostat settings, maintenance and variable-speed operation affect average power. This calculator models AC energy charges with one rate; it does not predict total household bills, startup peaks, demand charges or fixed utility fees. For time-of-use pricing, calculate each rate period separately and add the costs.
Method and worked examples updated . All examples are calculated from the displayed assumptions; no measured performance dataset is claimed.
Frequently asked questions
AC running costs, explained clearly.
Quick answers about watts, overnight cooling, tariffs and the downloadable estimate.
How much does a 1,200-watt AC cost to run for 8 hours?
At 75% average load and $0.27 per kWh, it uses 7.2 kWh and costs $1.944 per day, or $58.32 over 30 identical days. At 100% load, it costs $2.592 per day or $77.76 per 30-day month. These are illustrative inputs; use your unit’s power and your own tariff.
How much does it cost to run an AC all day?
Set daily runtime to 24 hours. A 1,200-watt AC at 75% average load and $0.27 per kWh costs $5.832 per day, or $174.96 over 30 identical days. Being switched on for 24 hours does not necessarily mean drawing rated power continuously.
What AC load factor should I use?
The default 75% is an illustrative assumption, not a measured or universal value. Use measured average power when available. At 100%, the calculation assumes rated input power throughout the entered runtime; this is not a guaranteed equipment maximum. If you enter measured average watts, set load to 100%.
Can I calculate AC electricity cost from BTU or tonnage?
BTU per hour and tons describe cooling capacity, not electrical input power. Prefer the manufacturer’s input watts. If a matching EER is available, input watts can be estimated as cooling capacity in BTU per hour divided by EER. Do not substitute SEER or SEER2 directly into that formula. Without an appropriate input-power estimate, capacity alone is insufficient.
Can this calculator compare window, portable, mini-split and central AC?
Yes, when you enter the electrical input and usage for each system. For central AC, include indoor blower power if it is not already included. Presets are illustrative examples, not typical ratings or efficiency rankings. Export each estimate and compare units suited to the same cooling requirement.
How do I enter cents per kWh or another currency?
Enter the price in the selected currency per kWh: 27 cents becomes 0.27 USD, while 30 yen becomes 30 JPY. Changing currency changes the label and formatting; it does not convert rates. Check the price each time you change currency.
Does the estimate include time-of-use rates and fixed charges?
No. It applies one electricity price to the calculated energy use. For time-of-use tariffs, calculate each time block separately and add the costs. Fixed charges, demand charges, taxes and other appliances are not automatically included. You can include applicable per-kWh charges in the rate you enter.
What is included in the downloaded CSV?
The CSV contains the inputs, energy use, hourly through seasonal costs, lower-runtime and lower-load scenarios, and calculation assumptions. It is generated in your browser without an account or email address. The prefilled example can be exported immediately; edit the inputs first for a personal estimate.
Are calculator inputs uploaded or saved between visits?
Calculator inputs and CSV generation stay in your browser. This page does not save your inputs between visits; download the CSV to keep them. No account or email address is requested.
Keep the assumptions.
Take the cooling budget with you.
Download your current AC inputs, energy use and cost comparisons in one CSV. Then change the wattage or runtime to plan another room.
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