How do I calculate the power consumption per day from the watt?

How do I calculate the electricity costs via excel? My first attempt seems to me wrong ^^ in the network, unfortunately, there are only finished computers that do not help me.

Example:

I have 25 notebooks of the same type in one room. Each notebook consumes about 40W in full operation.

My approach: 25 * 40 * 0,23 = 230 euro. If it seems wrong, then a notebook would consume 9 euro of electricity per hour.

The 0.23 are the kw / h costs.

You have two mistakes in your calculation. 1. Compute watts with kilowatts without having to convert this which may cause the result to be incorrect by a factor of 1000. 2. If you calculate the whole thing for only one hour, if you want to have it for one day, you have to count 24 for the whole thing.

Correct would be 25 * (40W / 1000) * 0,23kwh * 24h = 5,52 euro / day

25 * 40 * 0,23 = 230 euro.

That can't be right from the units. Three factors multiplied can't yield €. Where should they come from?

It's best to always count with units.

For one thing, then you have the control that the calculation was correct when the appropriate unit comes out.

On the other hand, you would then have recognized that Kw are not equal to W.

Ah, thank you very much x)

Well, that goes…

0.23 Euro / kwh that is the electricity price of the provider

then one of them is Watt or Kilowatt and the other one time unit (probably in hours)

If I now just multiply the 25 and 40, I have kilowatt hours as a unit. Kilowatt hours times 1 / kilowatt hours and it cuts out.

Supplement the 25 is a lot, but your statement is not correct

If I now just multiply the 25 and 40, I have kilowatt hours as a unit

No. Since 25 and 40 have no unit, as a result, no unit can come out.

40 watts * 1h = 40 Wh = 0.04 Kwh

Only that is the consumption of an hour

x25 to count from one to 25 devices - logical.

Missing only x24 for a whole day

and 0,23 Euro / Kwh for the energy costs COST PER ENERGY

So yes

With units calculated it fits. My speech:-)

The mistake was in principle only by calculating without units to set the decimal places wrong and just that he had calculated it only for one hour

Exactly. Hence my suggestion to always count on units. Then you notice something like that.

Before you try Excel here, you should be aware of how the "electricity price" comes about:

You pay (in your example) 23c per consumed kilowatt hour (kWh).

So if you have a consumer with a power of 1000W (= 1kW) hanging on the grid for ONE hour, the 23c will cost you.

So, now try it again:

1 notebook → 40W

25 notebooks accordingly? W (? KW)

Turned on for 24 hours yield "total line" x 24 =? KWh

Price = Daily consumption x 0,23 euro (23c)