Laptop, Monitor and Mini PC Running Cost Calculator

No. Apple's environmental report puts the 13-inch MacBook Air (M5) at 3.69 W idle with the screen on, and Lenovo's ENERGY STAR filing puts a mainstream 15.6-inch V15 at 4.8 W on and ready. Even at the 65 W ceiling of a typical adapter, eight hours a day for a working year is under 140 kWh, and most of those hours sit far closer to the idle figure than the ceiling.

Usually, and by a wide margin at the desk. Lenovo declares 230 W peak for the Legion S7 16IAH7 but only 12.96 W on and ready; Dell's datasheet for the Alienware Aurora R13 tower shows 47.5 W on and ready and 149.6 W with the processor stressed, before a discrete graphics card under gaming load is added. The tower's idle alone is more than three times the laptop's, and idle is where most hours go.

A little, and less than most people expect. Apple measures the MacBook Air (M5) at 0.24 W asleep and 0.11 W shut down at 230 V, with the adapter drawing 0.03 W on its own once unplugged from the laptop; Lenovo's Legion S7 sleeps at 1.24 W. Left asleep for the 6,000 or so hours a year it is not in use, a 1 W draw comes to about 6 kWh, so the habit is cheap, but switching off at the wall removes it entirely.

Dell lists 0.3 W to 0.5 W in standby for the monitors in the presets, against 14.5 W to 32 W in use, so a monitor that sleeps with the PC costs almost nothing when idle. What matters is the brightness while it is on: the same 24-inch panel is 14.5 W at its default settings and 42 W at maximum brightness and contrast.

Yes, at every point on the curve. Lenovo's declaration for a ThinkCentre M70q Tiny shows 9.9 W on and ready and 135 W at full load, Apple measures the Mac mini (M6) at 4 W idle and 70 W with the processor maxed, and ASUS's ENERGY STAR filing for an Intel N200 box shows 6.7 W on and ready. Dell's Alienware Aurora R13 tower starts at 47.5 W on and ready, so its idle hours alone cost between five and twelve times a mini PC's.

It depends on what is on the screen. Dell's UK specification for the 27-inch Alienware AW2725DF QD-OLED lists 27.6 W in On mode and 130 W maximum, while its 27-inch S2721DGF IPS lists 32 W typical and 90 W maximum. An OLED lights each pixel individually, so a dark game or a dark desktop theme draws less than the IPS, and a full-screen white document at high brightness draws more, which is why its range is so much wider.

Use your bill if you have it. Ofgem's cap is an average unit rate for Direct Debit customers, and the actual rate varies by region, payment method and whether you are on a fixed deal, so the cap is a sensible default rather than your number. The standing charge is not part of the sum, because you pay it whether the laptop is on or not.

Of the presets, yes, but the gap to a mini PC is smaller than its size suggests. Raspberry Pi's documentation lists a typical active draw of 800 mA at 5 V, which is 4 W, the same as Apple's idle figure for the Mac mini and below the 6.7 W ASUS files for an Intel N200 mini PC. Running around the clock, each of those is in the region of 35 to 60 kWh a year.