Readings tell us what you used.
For each electricity register, subtract the previous reading from the current one. Gas readings need converting into kWh using the factors on your bill.
Business energy bill calculator
Your readings.
Your rates.
Your bill, explained.
Work out the cost of the energy you’ve used. Enter the figures from your bill or meter and see how the charges add up, one line at a time.
No contact details required
Electricity or gas
Itemised result
What this tool checks
See how your bill adds up.
Use your readings and tariff rates to estimate the cost of energy used over a period. We show usage, rates, standing charge, CCL and additional charges separately, so you can see how the total is built.
- Your readings
- Your rates
- Your estimated bill
Let’s work through your bill.
Have your readings and tariff details to hand.
No sign-up. Your own rates.
How would you like to start?
Start with your bill.
We’ll extract the readings, dates, rates and charges for you to check before calculating.
Choose one bill for one supply. PDF, JPEG, PNG or WebP, up to 10 MB.
- Upload your bill
- Check the extracted figures against the bill
- Add missing details or a current meter reading
- Calculate your bill
Your file is securely uploaded to Smart Energy for extraction. Check every prepared figure against your bill. Tax rates, gas conversion factors and any missing charges must be entered or confirmed by you. Uploading does not request a quote. Privacy policy.
- 01 · Supply
- 02 · Period
- 03 · Figures
- 04 · Review
Which fuel are you checking?
Calculate one supply at a time. You can check your other fuel afterwards.
Check the unit printed beside the meter display.
Manual entries stay in this browser until you send a quote request.
Which period are we checking?
Use two reading dates. If you’re checking an invoice, use its stated number of standing-charge days.
Initially the elapsed days between readings. Change this if your bill states a different chargeable period.
Readings first. Then the rates.
Copy each register separately and enter rates in pence, excluding VAT. For example, £0.25 per kWh is 25p.
CCL starts at 0.801p/kWh, the main rate from 1 April 2026. Change it to match your bill, including 0 if exempt. Choose 5% VAT only where it applies to your supply.
These values convert meter units into kWh. Imperial readings are converted using 2.83 m³ per 100 ft³. The calculation is shown in your result.
Add other charges from your bill
Only add charges billed separately from your unit rate. Choose the basis shown on your invoice; rates below exclude VAT.
Energy used × rate in p/kWh ÷ 100.
Ready to add it all up?
Check the readings, rates and period below. You can go back and change anything before calculating.
This estimates the charges entered. It excludes balances brought forward, payments, credits and any charges you haven’t added.
Your calculation
Smart Energy Estimated business energy bill
Total consumption
Estimated charges including VAT
How the total is calculated
This is an estimate, not a supplier invoice or confirmation that the tariff is correct. Only the charges you entered are included. Download a copy if you’d like to share it with our team.
Want to compare these rates?
You’ve checked the cost. Use these figures to request suitable supplier offers for your next contract. Just add your business and contact details.
Check my current rates →
No obligation to accept a quote.
Your next contract
Let’s find suitable quotes.
A little help with the figures
Keep your bill handy.
We’ll do the maths.
You don’t need to know every term on the invoice. Start with the readings, dates and rates. Here’s where each part fits.
Your tariff puts a price on it.
The unit rate prices the energy. The standing charge is a daily cost, even when you use no energy. Keep pence and pounds separate when copying the figures.
The other lines matter too.
Add separately billed charges once, then enter the CCL and VAT values that apply to your invoice. Missing charges will make the estimate lower than the bill.
Before you compare
A few useful
checks.
How do I convert metric gas readings to kWh?
Subtract the previous reading from the current reading to find the volume used in m³.
m³ used × correction factor × calorific value ÷ 3.6 = kWh.
Example: 100 m³ × 1.02264 × 39.2 ÷ 3.6 = 1,113.54 kWh.
How do I convert imperial gas readings to kWh?
For a meter recording hundreds of cubic feet, first multiply the reading difference by 2.83 to convert it to m³.
Units used × 2.83 × correction factor × calorific value ÷ 3.6 = kWh.
Example: 100 units × 2.83 × 1.02264 × 39.2 ÷ 3.6 = 3,151.32 kWh. If your volume is already stated in individual ft³, use 0.0283 instead of 2.83.
Which gas conversion figures can change between bills?
Calorific value measures the gas’s energy content in MJ/m³ and can vary between billing periods. The examples use 39.2; use the value on the bill you are checking.
1.02264 is the usual temperature and pressure correction factor. 3.6 converts megajoules to kWh. Check your bill’s factors, especially where the supply uses volume correction equipment.
Why is my supplier’s total different?
Check the reading dates, number of chargeable days, rates and separately billed charges. Your invoice may also include an earlier balance, payments or credits. This tool calculates the period’s entered charges, rather than the account balance.
What if a reading is lower than the previous one?
Check you’ve copied the correct register and meter serial number. A meter replacement or rollover needs a separate calculation. Don’t alter the reading simply to make the calculator accept it; our team can help check the evidence.
Can this tell me if I’m on a good rate?
It shows the cost of the rates you enter. It doesn’t compare supplier offers. If you want to review your contract, send our team a recent bill and your renewal information.
Can I upload a bill instead?
Choose Upload my bill at the start of the calculator. Upload a PDF or clear photo of one supply’s bill. We prepare the figures for you to check against the original, then ask you to complete anything missing. You can edit every figure before calculating.
Do you need my contact details?
No. You can calculate and download the result without providing contact details. Manual calculations run in your browser. Choosing the upload route sends your bill to Smart Energy to prepare the figures. Your contact details are only needed if you request a quote.
Take the next step, if you need it
Understand the bill.
Choose what’s next.
Looking for a new contract, an explanation for a charge or help planning a renewal? Speak to our team.
