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kW to kWh Calculator

Multiply power by time: enter the kilowatts and how long the device runs, and see the energy in kWh, what it costs and what it adds up to each month and year.

Last updated:

kW
kWh
hours · minutes
Run time:
 

Step-by-step calculation

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    How to use the kW to kWh Calculator

    1. Enter the power in kilowatts (watts ÷ 1,000).
    2. Set the run time in hours and minutes, or click a preset such as 30 min or 8 hours.
    3. Add your electricity price per kWh to see the cost (optional).
    4. Set the days used per month to get monthly and yearly totals for a daily routine.
    5. Need kW from kWh? Type in the kWh box or press ⇄.

    kW to kWh formula

    kWh = kW × hours
    1. Find the power of the device in kilowatts (watts ÷ 1,000).
    2. Convert the run time to hours (minutes ÷ 60).
    3. Multiply power by time to get energy in kilowatt-hours.

    Worked example: a 1.5 kW space heater running 4 hours a night uses 1.5 × 4 = 6 kWh per night. At $0.17 per kWh that costs 6 × 0.17 = $1.02 a night, or about $30.60 over a 30-day month.

    Short runs work the same way: a 1.2 kW microwave used for 45 minutes → 1.2 × 0.75 h = 0.9 kWh.

    Reverse formula: kW = kWh ÷ hours. Example: 9 kWh used over 6 hours is an average of 1.5 kW.

    kW is a rate (how fast energy is used); kWh is an amount (how much was used). Your utility bills you for kWh.

    kW to kWh table

    Values below are for the run time set in the calculator (4 hours by default). Click any row to load it.

    kW to kWh over 4 h

    KilowattsKilowatt-hours
    1 kW4 kWh
    2 kW8 kWh
    3 kW12 kWh
    4 kW16 kWh
    5 kW20 kWh
    6 kW24 kWh
    7 kW28 kWh
    8 kW32 kWh
    9 kW36 kWh
    10 kW40 kWh
    11 kW44 kWh
    12 kW48 kWh
    13 kW52 kWh
    14 kW56 kWh
    15 kW60 kWh
    16 kW64 kWh
    17 kW68 kWh
    18 kW72 kWh
    19 kW76 kWh
    20 kW80 kWh
    21 kW84 kWh
    22 kW88 kWh
    23 kW92 kWh
    24 kW96 kWh
    25 kW100 kWh
    26 kW104 kWh
    27 kW108 kWh
    28 kW112 kWh
    29 kW116 kWh
    30 kW120 kWh
    31 kW124 kWh
    32 kW128 kWh
    33 kW132 kWh
    34 kW136 kWh
    35 kW140 kWh
    36 kW144 kWh
    37 kW148 kWh
    38 kW152 kWh
    39 kW156 kWh
    40 kW160 kWh
    41 kW164 kWh
    42 kW168 kWh
    43 kW172 kWh
    44 kW176 kWh
    45 kW180 kWh
    46 kW184 kWh
    47 kW188 kWh
    48 kW192 kWh
    49 kW196 kWh
    50 kW200 kWh
    51 kW204 kWh
    52 kW208 kWh
    53 kW212 kWh
    54 kW216 kWh
    55 kW220 kWh
    56 kW224 kWh
    57 kW228 kWh
    58 kW232 kWh
    59 kW236 kWh
    60 kW240 kWh
    61 kW244 kWh
    62 kW248 kWh
    63 kW252 kWh
    64 kW256 kWh
    65 kW260 kWh
    66 kW264 kWh
    67 kW268 kWh
    68 kW272 kWh
    69 kW276 kWh
    70 kW280 kWh
    71 kW284 kWh
    72 kW288 kWh
    73 kW292 kWh
    74 kW296 kWh
    75 kW300 kWh
    76 kW304 kWh
    77 kW308 kWh
    78 kW312 kWh
    79 kW316 kWh
    80 kW320 kWh
    81 kW324 kWh
    82 kW328 kWh
    83 kW332 kWh
    84 kW336 kWh
    85 kW340 kWh
    86 kW344 kWh
    87 kW348 kWh
    88 kW352 kWh
    89 kW356 kWh
    90 kW360 kWh
    91 kW364 kWh
    92 kW368 kWh
    93 kW372 kWh
    94 kW376 kWh
    95 kW380 kWh
    96 kW384 kWh
    97 kW388 kWh
    98 kW392 kWh
    99 kW396 kWh
    100 kW400 kWh

    kWh to kW over 4 h

    Kilowatt-hoursKilowatts
    1 kWh0.25 kW
    2 kWh0.5 kW
    3 kWh0.75 kW
    4 kWh1 kW
    5 kWh1.25 kW
    6 kWh1.5 kW
    7 kWh1.75 kW
    8 kWh2 kW
    9 kWh2.25 kW
    10 kWh2.5 kW
    11 kWh2.75 kW
    12 kWh3 kW
    13 kWh3.25 kW
    14 kWh3.5 kW
    15 kWh3.75 kW
    16 kWh4 kW
    17 kWh4.25 kW
    18 kWh4.5 kW
    19 kWh4.75 kW
    20 kWh5 kW
    21 kWh5.25 kW
    22 kWh5.5 kW
    23 kWh5.75 kW
    24 kWh6 kW
    25 kWh6.25 kW
    26 kWh6.5 kW
    27 kWh6.75 kW
    28 kWh7 kW
    29 kWh7.25 kW
    30 kWh7.5 kW
    31 kWh7.75 kW
    32 kWh8 kW
    33 kWh8.25 kW
    34 kWh8.5 kW
    35 kWh8.75 kW
    36 kWh9 kW
    37 kWh9.25 kW
    38 kWh9.5 kW
    39 kWh9.75 kW
    40 kWh10 kW
    41 kWh10.25 kW
    42 kWh10.5 kW
    43 kWh10.75 kW
    44 kWh11 kW
    45 kWh11.25 kW
    46 kWh11.5 kW
    47 kWh11.75 kW
    48 kWh12 kW
    49 kWh12.25 kW
    50 kWh12.5 kW
    51 kWh12.75 kW
    52 kWh13 kW
    53 kWh13.25 kW
    54 kWh13.5 kW
    55 kWh13.75 kW
    56 kWh14 kW
    57 kWh14.25 kW
    58 kWh14.5 kW
    59 kWh14.75 kW
    60 kWh15 kW
    61 kWh15.25 kW
    62 kWh15.5 kW
    63 kWh15.75 kW
    64 kWh16 kW
    65 kWh16.25 kW
    66 kWh16.5 kW
    67 kWh16.75 kW
    68 kWh17 kW
    69 kWh17.25 kW
    70 kWh17.5 kW
    71 kWh17.75 kW
    72 kWh18 kW
    73 kWh18.25 kW
    74 kWh18.5 kW
    75 kWh18.75 kW
    76 kWh19 kW
    77 kWh19.25 kW
    78 kWh19.5 kW
    79 kWh19.75 kW
    80 kWh20 kW
    81 kWh20.25 kW
    82 kWh20.5 kW
    83 kWh20.75 kW
    84 kWh21 kW
    85 kWh21.25 kW
    86 kWh21.5 kW
    87 kWh21.75 kW
    88 kWh22 kW
    89 kWh22.25 kW
    90 kWh22.5 kW
    91 kWh22.75 kW
    92 kWh23 kW
    93 kWh23.25 kW
    94 kWh23.5 kW
    95 kWh23.75 kW
    96 kWh24 kW
    97 kWh24.25 kW
    98 kWh24.5 kW
    99 kWh24.75 kW
    100 kWh25 kW

    Common values over 4 h

    KilowattsKilowatt-hoursExample
    0.01 kW0.04 kWhLED bulb (10 W)
    0.1 kW0.4 kWhTV or laptop setup (100 W)
    0.15 kW0.6 kWhRefrigerator (running)
    0.5 kW2 kWhGaming PC under load
    1 kW4 kWhMicrowave oven
    1.5 kW6 kWhSpace heater
    2.4 kW9.6 kWhElectric oven element
    3.5 kW14 kWh3-ton central AC
    4.5 kW18 kWhElectric water heater element
    7.2 kW28.8 kWhLevel 2 EV charger
    11 kW44 kWh11 kW EV charger

    Tips for estimating electricity use

    • Find the rating on the nameplate or charger label. If it lists watts, divide by 1,000; if it lists only volts and amps, multiply them and divide by 1,000 for an approximate kW.
    • Cycling appliances such as refrigerators, AC units and thermostatic heaters do not draw full power all the time. Multiply the run time by the share of time they are actually on, or use a plug-in energy meter for a real reading.
    • Use your own price. The default of $0.17 per kWh is only an example close to recent US residential averages; your bill shows your actual rate, which may include delivery charges or time-of-use pricing.
    • EV charging: energy taken from the wall is slightly more than what reaches the battery, because of charging losses of roughly 10%.

    Frequently asked questions

    How do you convert kW to kWh?

    Multiply the power in kilowatts by the time in hours: kWh = kW × hours. A 2 kW device running for 3 hours uses 6 kWh.

    Is 1 kW the same as 1 kWh?

    No. kW measures power (the rate of energy use) and kWh measures energy. A 1 kW appliance uses 1 kWh only if it runs for exactly one hour.

    How many kWh does a 1.5 kW heater use in a day?

    Running continuously for 24 hours it uses 1.5 × 24 = 36 kWh. Most heaters cycle on and off with a thermostat, so real use is usually lower.

    How do I convert minutes to hours for the formula?

    Divide the minutes by 60. 45 minutes is 0.75 hours, so a 1.2 kW microwave used for 45 minutes uses 1.2 × 0.75 = 0.9 kWh.

    How much does it cost to run a 1 kW appliance for an hour?

    It uses 1 kWh, so the cost equals your price per kWh. At $0.17 per kWh that is 17 cents per hour.

    How many kWh does a 7.2 kW EV charger deliver in 8 hours?

    7.2 kW × 8 h = 57.6 kWh drawn from the grid. A little of that is lost as heat during charging, so slightly less reaches the battery.

    Are all the tools on FreeToolCabin tested for quality and accuracy?

    Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.

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