Mobile & Electronics

Laptop Power Cost Calculator

What your laptop costs to run a month - using its own power draw, not an assumed one.

6 inputs Free, no sign-up

Your figures

The charger's rating is printed on the brick and is a fair upper bound. Actual draw while you work is usually well below it.

Use fewer for something you only run at weekends.

Rupees per unit (kWh), from your own bill. Tariffs differ by state, by connection and by how much you use, so this is the figure the result is most sensitive to.

Try an example

Result

Your result

Enter your figures and the result appears here.

Estimates only. Rates, fees and specifications change. Confirm against the official source before you rely on a figure — see our disclaimer.

About this calculator

Laptops are cheap to run, and the figure surprises people in the useful direction. A 65 W laptop worked eight hours a day costs somewhere around a hundred and thirty rupees a month at a typical Indian tariff — less than most people assume, and far less than the desktop it probably replaced.

No wattage is assumed here. A 13-inch ultrabook and a gaming laptop differ by a factor of five, so the number has to be yours.

How to use this calculator

  1. Find your charger's wattage — it is printed on the power brick, often as an output voltage and current to multiply, or directly in watts.
  2. Use that as an upper bound, or a lower figure if you know your actual draw. A laptop idling or browsing typically uses a third to a half of its charger's rating.
  3. Enter the hours a day you use it and your rate per unit.

The formula

Units a day  = Watts x Hours / 1000
Cost a month = Units a day x Days x Rate

The charger rating is the ceiling: it has to cover the machine at full load while also charging a flat battery. Most of the time a laptop draws well under it, so a cost worked out from the charger rating is a comfortable overestimate rather than a surprise.

SymbolMeaningUnit
P Laptop power draw W
Hours Hours a day in use h
Rate Your tariff per unit Rs/kWh

Worked example

A 65 W laptop, 8 hours a day, at ₹8.50 a unit:

Units a day  = 65 x 8 / 1000 = 0.52
Cost a month = 0.52 x 30 x 8.50 = Rs 132.60
Cost a year                      = Rs 1,591.20

At half that draw — realistic for office work — it is about ₹66 a month.

Notes and limits

  • The charger rating covers full load plus battery charging. Typical use is well below it, so the calculated figure is an upper bound.
  • Gaming, video editing and compiling push a laptop toward its rating. Browsing and documents do not.
  • A laptop left plugged in with a full battery draws only what the machine itself needs; it does not keep pouring energy into a charged battery.
  • The charger uses a small amount even with nothing connected. It is a fraction of a watt to a watt or two, and is not counted here.
  • No laptop's specification is shipped with this calculator. The figure comes from your brick.

What this calculation assumes

  • The wattage entered is drawn for the whole of the usage time.
  • Using the charger rating gives an upper bound; typical draw is lower.
  • Charger standby consumption is not included.

Frequently asked questions

How much electricity does a laptop use per month?

For a 65 W laptop used eight hours a day, roughly 15 units a month, which at Rs 8.50 is about Rs 133. Actual use is typically lower, because a laptop rarely draws its charger's full rating.

What wattage should I use?

Start with the charger's rating from the power brick - that is the ceiling. If you mostly browse and write, half of it is a closer estimate. This page does not assume a figure, because laptops vary enormously.

Is a laptop cheaper to run than a desktop?

Almost always, and usually by a wide margin. A desktop with a monitor commonly draws two to five times what a laptop does for similar work.

Does leaving it plugged in cost more?

Barely. Once the battery is full, the machine draws what it needs to run and the charger stops pushing energy into the battery. The idle charger itself uses a fraction of a watt.

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