Work out your laptop electricity consumption in seconds: enter the wattage on your laptop's label, its hours of use per day and your electricity rate, then click Calculate. You get your daily, monthly and yearly cost and total kWh consumption straight away. Those same results also cover laptop power consumption. Also see printer power consumption.
Wondering how much your laptop electricity consumption adds to the bill? The short answer is that most laptops draw between 15 and 65 watts, which works out to roughly 20 to 35 dollars a year. This guide explains the electricity usage of a laptop in plain terms: how many watts it uses, what pushes the wattage up or down, and how to convert your own laptop's power draw into kWh and cost.
A laptop does not pull one fixed number of watts. Its power use swings with what you are doing, how bright the screen is and whether the battery is charging. Think in three bands: idle, typical workload and peak. A thin notebook such as a MacBook Air, a Dell XPS or a ThinkPad may idle at 4 to 9 watts, settle near 15 to 45 watts for a normal day of documents, browser tabs and a video call, and briefly touch 60 watts or more when it boosts.
Ultraportables use efficient processors and integrated graphics, so their wattage stays low. For an 8-hour workday of email, spreadsheets and streaming, an average draw of 20 to 40 watts is common, which is about what a bright LED bulb uses.
A gaming laptop adds a discrete graphics card and a high-refresh panel, so it commonly runs at 90 to 150 watts while a game is loaded and can spike higher for a few seconds. Video editing and 3D rendering push a workstation the same way. These machines ship with 180 to 240 watt power adapters for that reason.
Idle draw matters because many people leave a laptop on all day. A screen-on idle of 6 to 10 watts is cheap, but a laptop that never sleeps still runs up hours. Peak draw is short, so it barely moves your yearly total unless you game or render for hours.
You only need three numbers to estimate laptop energy consumption: the average watts, the hours of use per day and your electricity rate. The calculation is a straight multiplication, then a division by 1,000 to convert watts into kilowatts.
Formula:
$$\text{Daily kWh} = \frac{\text{Watts} \times \text{Hours per day}}{1{,}000}$$ $$\text{Yearly cost} = \text{Daily kWh} \times 365 \times \text{Electricity rate (per kWh)}$$Take a laptop that averages 41 watts across 7.25 hours per day. Multiply 41 by 7.25 to get 297.25 watt-hours, then divide by 1,000: that is 0.297 kWh per day. Over a 30-day month the laptop uses about 9.0 kWh, and across a full year it uses about 108.5 kilowatt-hours.
Now apply an electricity rate. At 18.73 cents per kWh, 108.5 kWh costs $20.32 per year, or about $1.69 per month. If your average electricity rate were 31.2 cents instead, the same laptop would cost about $33.85 a year, because the cost scales directly with the rate.
The table keeps the 7.25 hours a day and 18.73 cent rate fixed and changes only the average wattage, so you can see how the wattage alone moves the electricity bill.
| Average draw | Typical situation | kWh per year | Cost per year |
|---|---|---|---|
| 14 W | Idle, dim screen, light reading | 37.0 kWh | $6.94 |
| 26 W | Browsing and documents on battery saver | 68.8 kWh | $12.89 |
| 41 W | Typical workload with a video call | 108.5 kWh | $20.32 |
| 63 W | Multitasking while the charger tops up the battery | 166.7 kWh | $31.23 |
| 118 W | Gaming laptop under load | 312.3 kWh | $58.49 |
A 118 watt gaming session for the whole 7.25 hours is an extreme case, so treat the last row as a ceiling, not an average.
Two laptops with the same battery can show very different power draw because several parts of the machine each take a share of the watts. These are the largest ones.
The CPU and GPU are the biggest swing factor. A low-power processor sips a few watts at rest, while a performance chip with a discrete graphics card can draw ten times that under load.
The display is often the single largest steady draw. A 17-inch panel at full brightness uses noticeably more than a 13-inch one at half, and a 4K or OLED screen can add several more watts.
While the battery is below full, the laptop spends extra watts on charging, usually 5 to 15 watts on top of the work it is doing. Once it is plugged in at 100 percent, that extra draw falls away. Running on the battery alone also costs a little more in conversion losses when you recharge.
Every peripherals add-on draws power: an external drive, a USB-C hub, a phone charging from the port and especially an external monitor, which also raises graphics activity.
Programs running in the background, dozens of open browser tabs and sync clients keep the processor out of its deepest rest state. Heavy loads also spin up the cooling fans, which add a small but real draw of their own, and a warm room makes the cooling work harder.
An adapter left in the wall outlet with no laptop attached still draws a trickle. A modern GaN or USB-C unit uses well under a watt, but an old barrel-style brick can sit at 2 to 3 watts. At 2.3 watts around the clock, that is 20.2 kWh and about $3.77 a year for nothing.
Once you know the watts, the cost to run a laptop is a single multiplication, and the same arithmetic works for any computer you want to compare. For a typical laptop the answer is a few dollars a year up to roughly twenty or thirty, in line with the 15 to 65 watt range above, which keeps computer energy usage a small slice of your household total.
Dividing the yearly figure by 12 gives your cost per month: $1.69 for the 41 watt example. If that laptop runs for a full 24 hours, it uses 0.984 kWh and costs about 18 cents at the same rate, which is why an always-on machine adds up faster than a laptop you close at night. This laptop-level view of power usage also tells you whether a high bill comes from the laptop or from something else in the house.
Screen size shows up directly in the wattage rows of the table above: a 16-inch panel needs more backlight power than a 13-inch one, so it lands nearer the 63 watt row at the same brightness. A newer low-power chip lowers every row, and that efficiency gain is the reason to compare typical-load wattage, not just battery life, when you buy.
The biggest energy savings for a laptop are habits: close the lid, sleep early and avoid heavy tasks at full brightness. Moving from a desktop to a laptop saves more than any setting, because desktop computers start from a higher baseline. Lower use also trims carbon emissions, and the savings appear on the next bill; the reduction tips further down cover the details.
Laptops are built around a battery, so they are designed to be frugal. A desktop typically draws 200 to 500 watts under load, while a laptop averages a fraction of that. Using the same 7.25 hours per day and the same rate, a 300 watt desktop would use 794 kWh and cost about $148.73 a year, roughly seven times the $20.32 of the 41 watt laptop. For a household's overall energy usage, swapping a desktop for a laptop is one of the easier wins.
Field metering supports this: a study of computers in homes measured laptops at about 75 kWh per year on average, with a median near 31 kWh, which is much lower than desktops. The gap between mean and median shows that a few heavy users pull the average up, so your own annual energy consumption may be well below the average.
Because the totals are small, no single change transforms the bill, but the habits below stack up across many hours and a whole household of devices. Browse more appliances with our appliance electricity usage calculator.
Switch the power settings to a balanced or power-saving mode. It limits how hard the processor boosts and dims the panel sooner, which lowers the wattage with no change you will notice during light work. A low-power profile helps most on a gaming rig that you only use for documents.
Set the laptop to sleep after a few minutes away and hibernate overnight. A sleeping laptop sits in standby at a watt or two, versus a screen-on idle ten times higher.
Turn down screen brightness or enable adaptive brightness so it follows the room. It is the quickest saving because the backlight runs the whole time you work.
Remove accessories you are not using and unplug the charger when you are away. A smart plug with energy monitoring shows your true wattage in real time, so you can replace estimates with measured numbers.
If your utility offers a time-of-use plan, run renders, backups and big downloads during off-peak hours. The energy is the same, but the price per kWh is lower.
A laptop is among the cheapest appliance on the circuit, far below an air conditioner or a dryer, and its 108.5 kWh a year is a small environmental impact. A single 350 watt solar panel produces more than enough in a sunny day to cover a laptop's daily use, so a solar setup is easy to size for a laptop or any other computer, including a desktop computer and a home-office computer or two. A portable power station or a small UPS can each carry that load easily, and an Energy Star monitor or dock trims the rest.
Check each computer you own the same way: a laptop, a second family computer and an old tower each get their own wattage, and the computer with the highest draw usually deserves the first look. Solar sizing, a battery backup or a plan to cut your bill all start from that one wattage figure.
A few practical limits apply. Your own wattage will not match a published average, so read the rating on the adapter for the maximum draw and use a plug-in meter for the real figure. The volts times amps on the label give the maximum in watts, not what the laptop uses day to day. Because the wattage figure is only an average, treat the yearly estimate as a range rather than an exact result.