Ever since I needed to pay my own electricity bill because I no longer stay with my parents, it is important that I know how to calculate the electricity usage and charges for every electronic devices and electrical appliances. This knowledge will allow me to conserve energy and save money at the same time by not simply wasting the energy in the first place. Most of the time when we purchase electrical appliances such as a television, you will find the power consumption being mentioned in the technical specifications. One example is the Panasonic 50″ Smart VIERA Plasma TV that stated 142W for “On mode Average Power Consumption”.
(W) stands of Watt and this piece of information is very important to calculate the usage charges. This is the information that you need to calculate the usage of the electrical appliances that you use in hours. Some doesn’t display Watt, but only Volt (V) and Ampere (A). To get Watt, simply multiple volt with ampere. For example V x A = W. Once you know the Watt, next thing you need to know is the current tariff rates offered by your electric utility company.
The current tariff and pricing rates in Malaysia by Tenaga Nasional Berhad (TNB) for residential consumer are as shown at the image below. You can also access the official TNB tariff webpage here.
The rates clearly shows that the more electricity your home uses, the more expensive it gets. Since the tariff are given in kWh (kilowatt hour), here is the formula to convert the Watt and Hour into kWh.
W x Hours / 1000 = kWh
Once we have the kWh, all we need to do now is to multiple with the rates given by Tenaga Nasional Berhad. Let us try calculating a few electrical appliances and see how much it cost to use them.
If you use a Philips 9W LED light bulb for 10 hours daily. How much would it cost per month?
First we need to get the kWh:
9W x 10Hours / 1000 = 0.09 kWh
Once we have the kWh, we are able to calculate how much it cost to use per day.
0.09kWh x 21.8(rate) = 1.962sen per day
For a whole month, just multiply 1.962 with 30 because a month consists of 30 days.
1.962sen x 30days = 58.86sen
We can clearly see that the Philips 9W LED light bulb is truly an energy saver because it only cost 58.86 cents per month if we use it 10 hours a day. The calculation formula is the same throughout the whole world, except for the rates offered by your country’s electric provider.
Let’s try another calculation that consumes more power. You boil water everyday for one hour using Burco’s 4 liter fast boiling with high power heater (2.4kW) kettle. How much is the charges for the whole month?
2.4kW x 1hour = 2.4kWh
2.4kWh x 21.8sen = 52.32sen
For the whole month, 52.32sen x 30 = 1569.6sen which equivalents to RM15.696
Since this is a fast boiling kettle with high power heater, it probably takes only 10 minutes to boil the water instead of an hour. Simply divide 53.32sen with 6, and it cost nearly 9 cents (8.72sen to be exact) to boil a water with this kettle.
If you need to know the electricity usage accurately, you will need to use an energy use monitor device such as the Belkin Conserve Insight. Just plugin the device to a power socket and then plug in the appliance that you want to monitor in the Belkin Conserve Insight outlet.
There is an online electricity bill calculator available in Tenaga Nasional Berhad’s website where you only need to select the category type and enter the total consumption in kWh to get your estimated bill. By comparing the electric usage from your previous electric bill and the current usage displayed on the meter to get the total kWh usage, you are able to get an instant estimation of your new electricity bill.
Saya mau tanya cara hitung biaya pemakaian listrik misal Daya saya 33.000 VA tanpa Kwh Meter, hanya berdasarkan Total besar Ampere yang ada pada NCB, Bagaimanakah carannya
Dear Sir,
Can I know how to calculate machine electricity usage per hour if I have below information:-
Voltage :3 Phase (415V)
Ampere : 38 Amp
What about usin de current/voltage given, to multiple by the days or hours,nd at the same time divide 1000, ist wrong formula?
I am urgently needing the charges for electricity usage per kWh for Ekurhuleni Gauteng region. I am being charged R1.94 per kWh, and my bill for 5 people is around R7400.00 per month. Is this Normal!!!!!
what does the unit ‘LS’ means?
please give me a reply…
On the adapter I use for my equipment, it has both input,output voltage/current. Which one I should use for my power calculation?
How to calculat tnb bills and what is the formula to do that?
If I have a transmission wheeling rate of $1.08/KW-Month, how do I covert that to $s/KWh?
how to apliance power factro in the calcuation. due to it will give some impact on ur actual kwh at tnb meter.
Thanks very useful information. :)
My question , How to select the MCB for control panel for example :- My control panel carry 1 Amp MCB . we have install 20 control module in one panel and each control module carry 10Va how to size up the MCB on this situation and what is the cal formula .
on how to save electrical bill.Did any gadget in market now can be use
example;
Hi! Ju to say…thanks a lot…it was very useful…
Keep up a good work…
Cheers!
Hi Raymond,
I intend to change my fixed subscription Sintel phone to a Star Hub free phone which plug into a internet broadband Modem, but this modem require electric, the information I got on the modem:
+12VDC 0.75A, if this modem power on for 24 hrs/30 days, how to calculate the consumption in kWh?
Hi Mr Raymond,
I have some dificulities on calculations.
i need to know how much my electricity charges for
9units of 4 hp a/c , running 24 hrs for 30 days.
Dear Raymond,
I was wondering on how do you calculate the,
‘For the first 200 units per month: 0.218 cents
For the next 800 units per month: 0.258 cents
For each additional units per month: 0.278 cents’ ?
Is it given by the government or do we have to calculate it by ourselves?
Something wrong with the first 200 unit in my bill. Last month nobody was there, the only appliance consume electric was 1 wireless router which I doubt consumed 200 unit but still we got the first 200 charges and some more extra unit. WTF?
Should it be the exact unit calculated (I got the N bill) or although we use less that 200 unit per month, TNB’s minimum charges is still 200 unit? I thought it’s rm3.00 minimum charge? WTF TNB, WTF..?
answer for lumpis
5hpx.746x.28senxhours usedx30days
Hi Mr.Raymond,
can you tell me what is suitable formula to calculate this item below.
Item: Air-condition
Brand: York
Horsepower: 5hp
Phase: 3 phase
can anyone give me an idea how much electricity would a 2.oo kw electric fire use if it was on for 4 hours a day and the appx cost in real terms
1. Tariff A – Domestic Tariff
For Monthly Consumption Between 0-400 kWh/month
For the first 200 kWh (1 – 200 kWh) per month sen/kWh 21.80
For the next 200 kWh (201 -400 kWh) per month sen/kWh 34.50
The minimum monthly charge is RM3.00
For Monthly Consumption More Than 400 kWh/month
For the first 500kWh (1-500kWh) per month sen/kWh 30.00
For the next 100 kWh (501-600kWh) per month sen/kWh 39.00
For the next 100 kWh (601-700kWh) per month sen/kWh 40.00
For the next 100 kWh (701-800kWh) per month sen/kWh 41.00
For the next 100 kWh (801-900kWh) per month sen/kWh 43.00
For the next kWh (901 kWh onwards) per month sen/kWh 46.00
The minimum monthly charge is RM3.00
Dear Raymond,
Can you tell me will it be more efficient if i use LED to replace Energy saving light.
LED spec 12V, 20watt, 1.66amp
Energy saving 240V, 14watt, 0.058amp
I do not how to calculate when the volt is diffrent 12V vs 240V . Please advise
Thank You
hi..
i think u forgo something in ur calculation regarding kwh usage.
u need to know ur apliance power factro, due to it will give some impact on ur actual kwh at tnb meter.
so dont forget that.
Thanks Raymond – very informative.
Raymond, what is the average consumption of 3-split type aircon if use for 8 hours here in singapore? How much for each aircon? We’re using a Daikin (inverter type). Thanks.
I am also interested in 3 phase calculation as I changed from single phase to 3 phase & my bill went from RM150/month to RM521/month!
Above poster is correct too – tariff has gone up for the higher amounts though I have 253 units @ 0.218 and 1013 units @ 0.289 before the last 694 units @ 0.312.
you need to update the electricity tariff. first 200 units still costs the same. the next 800 units costs 28.9 cents/unit and more usage costs 31.2 cents/unit.
How about for three phase calculation ?
azman, definately your electric charges will go up if your fridge didn’t cool propertly.
Imagine your fridge have to work harder in order for your fridge to reach the cooler temperature that you set.
cool, my fridge didnt cool properly and suddenly the electricity bills went up by RM60 for the month, better check this out
this is good :)