# Checking Bulb calculations on Bill

Gas Sept sept-18 Bulb....

Read start 9418 end 9294 Units used 124

Energy 1381 kWh @ 2.73 =£37.67

**I calculate that as £37.70 using Bulbs figures and not £37.67, I also calculate the kWH as 1380.79 not 1381.**

Standing charge £7.25

Standing charge £7.25

Fuel discount -£1.21

Cost of gas £43.71

VAT £2.19

Total £45.90

**I had this working accurately before the Aug price rise but had to spend some time working out what was rounded up and what down and how many decimal points Bulb used when calculating. To save me doing this again would Bulb please advise on what is rounded up / down and what figures are used to how many decimal points in order to calculate the Bill.**

## Comments

I haven't carried out a search of the forum but there was a very similar discussion possibly about two months ago, which received a response from Bulb (can't remember the details).

Yes that is the same issue I have with the decimal points, I did query this when I joined but eventually fudged the figures like Zac to get a match.

If Bulb are going to use 4 decimal points then I would prefer this listed on all calculations, then of course we need to know if any are rounded up or down or not at all. It is only a few pence but is frustrating when you cant get the figures to match.

https://energylinx.co.uk/

@DanP at Bulb Can you please provide the

unit prices for West Midlands, to however many decimal places as are used in calculating the bill?ex-VATAnd the gas?

November 5, 2018 9:53AM Flag

@scudo I am afraid this is an issue with the amount of significant figures we are quoting. You can see your full rates through this link by putting in your postcode: https://bulb.co.uk/tariff/

November 5, 2018 9:53AM Flag

I am afraid this is an issue with the amount of significant figures we are quoting.

I dont quite understand the issue.

Its frustrating as the prices are vat and then non vat and then 3 decimal points and then just 2 decimal points depending on where the figures are sourced, they are all over the place. Its only a few pence but when you think you have got the formulas correct on the spreadsheet they dont balance up with Bulbs calculations.

The one that surprises me is that the actual figures they issue on the monthly statement are actually incorrect and don't add up.

Bulb has on statement....

Energy 1381 kWh @ 2.73 =£37.67that actually equates to £37.70.I would guess that the unit cost in your example to three decimal places is 2.728p, which means energy 1381 @2.728 = £37.673 to three decimal places or 37.67 to two decimal places.

As you know I also keep a spreadsheet of my energy usage and costs, and use the unit costs shown on my statement to arrive at my own bill calculations. This sometimes leads to my final costs not being the same as on the statement, nominally out by a couple of pence. Where this happens I have to overwrite the equation calculated costs by the figures shown on my statement.

If Bulb showed the actual unit costs to the correct number of places then this problem as you have already mentioned would alleviate any difference between Bulb total costs and customer calculated costs.

@DanP at Bulb has kindly provided the info I wanted for electric - just waiting for the info for gas.

Let me know if you need anything else

Electric looks fine, but the Midlands ex-VAT gas rate of 3·752 equates to a VAT inclusive price of 3·9396.

3·751 ex-VAT is closer, giving a VAT inclusive price of 3·93855.

3·750 ex-VAT gives a VAT inclusive price of 3·9375, which to three decimal places matches your published rate of 3·938.

Today's annual statement reveals that the VAT inclusive price

IS, after all, 3·9396.If I follow the "Our Tariff" link at the bottom of this page and enter my postcode it says 3·938.

If I look at my dashboard's "My account and tariff info" it says 3·94.

Please Bulb, can we have some clarity and consistency?

Those of us who use a calculator and/or spreadsheet would appreciate accurate figures, to as many decimal places as you actually use.

Those who don't would not be disadvantaged.

"Our bulb bills round the number to 2 decimal places to make the bills look simpler"

I replied niclely that making the bill look simpler might sound good, except for when they don’t plan for the mathematically adept among us.

I wish I'd added that it also makes the bill look WRONG, not to mention having a detrimental effect on trust!

It's the ONE thing that drives me nuts about Bulb.

The reason it drives me nuts is because it's so unnecessary and pointless.

When buying most goods or services, the only thing that matters to the consumer is the VAT inclusive price - to two decimal places of a pound (pence). I'm quoted a price - I pay it - all fine.

Energy is a little different, in that I'm NOT quoted an accurate rate, because, say Bulb, it keeps things "simple".

Really?

On the monthly statement the recorded kWh are multiplied by a VAT-exclusive rate to two decimal places. There's a daily standing charge of x days at, again, a VAT-exclusive rate to two decimal places. VAT is then added. Inevitably I have to apply a fudge factor to make my calculation equal to Bulb's figure for the total bill.

Having done that, I've merely proved that we're both right, or maybe, we're both wrong! It's hardly open, transparent and honest, like everything else is with Bulb.

Apart from asking on the forum, the only time I've seen accurate rates is in the annual statement, which of course in a volatile market isn't valid for very long.

Please, Bulb, show the actual, accurate rates that you're using to calculate my bill - or come up with a valid reason why you can't or won't.Yes I agree, your fudge factor is analogous to me having to do a manual calculation on my spreadsheet.

123 kWh @ 11.67 = £14.39 (I make that £14.35)

You explained you use 4 decimal points, so:

123 kWh @ 11.6736 equals £14.3585 or rounded up is £14.36

So I am still seeing a discrepancy. Can you please explain.

If they are going to stick as it is then please Bulb give us an explanation so we can at least put it to bed.

I couldn't be bothered to query it for such a small amount. But it does bother me that they seem to follow different mathematical rules.