How to Read Gas and Electricity Prices in the UK — Understand Unit Rates, Standing Charges & Calculate Your Bill

Confused by your energy bill? You’re not alone. UK gas and electricity prices are typically shown as a unit rate (pence per kWh) plus a daily standing charge, with 5% VAT added at the end. Once you know what each line means, you can check bills for accuracy, compare tariffs confidently, and spot real savings.

The basics: tariff components explained

Your energy cost is driven by a few core elements. Understanding these is the key to reading any bill:

• Unit rate (p/kWh): What you pay for each unit of energy you use. Electricity and gas are both billed per kilowatt-hour (kWh).
• Standing charge (p/day): A fixed daily fee to cover network and policy costs, paid whether you use energy or not.
• VAT (5%): Added to the subtotal of unit charges and standing charges.
• Tariff type: Single-rate, two-rate (Economy 7/Economy 10), prepayment, fixed or variable. Two-rate tariffs have separate day and night prices for electricity.
• Other line items: Any exit fees (for leaving a fixed tariff early), credits or refunds, and any balance adjustments.

Where to find your rates on a bill

Look on page one or two of your bill under “Your tariff” or “How we calculated your charges.” You should see:

• Electricity unit rate shown as, for example, 28.000p/kWh, and standing charge as 52.000p/day.
• Gas unit rate shown as, for example, 7.000p/kWh, and standing charge as 30.000p/day.
• Billing period (e.g., 01–30 April), and whether readings are Actual or Estimated.
• For two-rate meters, separate day and night kWh with distinct prices.

Unit rate vs standing charge: what matters most?

Both do. If you use low energy (e.g., a well-insulated flat), a lower standing charge can save more than a tiny unit rate cut. If you use high energy, the unit rate dominates. Always compare the total annual cost for your usage, not just one number.

• Regional differences: Prices vary by region and payment method (e.g., direct debit vs prepayment).
• Economy 7/Economy 10: Night rates are cheaper, day rates higher. Best if you can shift usage (e.g., storage heaters, EV charging).
• Price cap: Ofgem’s cap limits the rates on standard variable tariffs, not your total bill. Your cost still depends on how much you use.

How to check a bill: step-by-step

1. Find your usage (kWh): On the bill line for each fuel and rate.
2. Multiply usage by unit rate: kWh × p/kWh = pence; divide by 100 for pounds.
3. Add the standing charge: Daily standing charge × number of days in billing period.
4. Add VAT (5%): Multiply the subtotal by 1.05 to get the total.

Worked electricity example (illustrative only): 270 kWh in 30 days at 28p/kWh with a 52p/day standing charge.

• Unit cost: 270 × £0.28 = £75.60
• Standing charge: 30 × £0.52 = £15.60
• Subtotal: £75.60 + £15.60 = £91.20
• VAT (5%): £4.56
• Total: £95.76

Converting gas meter readings to kWh

Electricity is already in kWh. Gas meters measure volume (m³ or ft³), so suppliers convert to kWh using a standard method. Most modern meters are metric (m³). The standard formula is:

1. Work out volume used: current reading − previous reading = m³ used.
2. Apply volume correction (approx. 1.02264) and a typical calorific value (about 40.0 MJ/m³, varies slightly).
3. Convert to kWh: m³ × 1.02264 × calorific value ÷ 3.6.

Worked gas example (illustrative): 120 m³ used, CV 40.0 MJ/m³.

• kWh = 120 × 1.02264 × 40.0 ÷ 3.6 ≈ 1,363.5 kWh
• At 7.0p/kWh: 1,363.5 × £0.07 ≈ £95.45
• Standing charge: 30 days × £0.30 = £9.00
• Subtotal: ≈ £104.45; VAT 5% ≈ £5.22
• Total: ≈ £109.67

Your bill should show the conversion steps. If numbers look far off, check that the meter units (m³ vs ft³) and readings are correct, and contact your supplier if needed.

Fixed vs variable tariffs

• Fixed: Unit rates and standing charges are locked for a period (e.g., 12 months). Good for budgeting; may have exit fees.
• Variable: Rates can go up or down with the market and the Ofgem price cap if you’re on a standard variable tariff. Usually no exit fees.

Smart meters and accurate billing

• Smart meters send automatic readings, reducing estimates and billing errors.
• Use your In-Home Display to track live usage and costs by day/time, especially useful on Economy 7/Economy 10.
• Submit manual readings if your smart meter temporarily stops communicating to avoid estimated bills.

Practical ways to reduce your bill today

• Target high-usage appliances: heating, hot water, tumble dryers, ovens. Small tweaks here have the biggest payoff.
• Set thermostats wisely: 18–20°C for living areas; turn down hot water cylinder to a safe yet efficient level.
• Shift off-peak on two-rate tariffs: run washing machines, dishwashers and EV charging at night where safe and practical.
• Seal heat leaks: draught-proof doors, windows and letterboxes; insulate lofts and hot water pipes.
• Use smart schedules: programme heating and hot water to match your routine.
• Explore practical guides from Cheapest Utility Provider:
  • Sure! Here Are 10 Evergreen Blog Headlines Related To Saving Money At Home, Cutting The Cost Of Energy, And Finding Cheap Energy Options –
  • 10 Proven Tips To Slash Your Home Energy Bills And Save Money
  • The Ultimate Guide To Energy Efficiency – How To Reduce Costs At Home
  • Simple Ways To Save Money At Home – Cutting Energy Costs Made Easy
  • How To Make Your Home More Energy-Efficient – Top Strategies For Savings

When and how to switch supplier

If your usage is known, switching to a cheaper tariff can cut costs fast. Don’t fixate on the lowest unit rate alone—consider the standing charge and any exit fees from your current deal. Prepayment and two-rate tariffs can be compared too; just ensure you input the correct meter type and usage split (day vs night kWh).

1. Gather data: Last 12 months’ kWh for gas and electricity (from bills or your online account). If not available, use at least the last three months and seasonalise cautiously.
2. Compare deals: Use an accredited comparison tool to see total estimated annual costs for your usage, including VAT and standing charges.
3. Check terms: Look for exit fees, payment method, tariff end date, and any special conditions (e.g., paperless billing).
4. Start the switch: The new supplier handles the process. Provide final readings on the switchover date.
5. Cooling-off: You usually have 14 days to change your mind on a new contract.

Suppliers must refund any credit on your old account after your final bill. If you’re in debt on a prepayment meter, you may still be able to switch under certain conditions—check eligibility with your current supplier.

Common pitfalls to avoid

• Ignoring the standing charge: A rock-bottom unit rate can be offset by a very high daily fee.
• Comparing monthly direct debit amounts: These are estimates. Always compare per-kWh rates and total yearly cost for your usage.
• Estimated readings: Can cause bill spikes. Submit regular readings if not on a communicating smart meter.
• Wrong two-rate split: If you’re on Economy 7/Economy 10 but use most power in the day, you could pay more overall.
• Forgetting VAT: Some quotes show prices including VAT, others exclude—always check.
• Overlooking exit fees: These can wipe out savings if you switch too early from a fixed deal.

Quick checklist before you choose a new tariff

• Do you know your annual kWh for both fuels?
• Are you on the right meter/tariff type (single vs two-rate, prepay vs credit)?
• Are the quoted prices inclusive of VAT and standing charges?
• Have you read the tariff’s exit fees and end date?
• Will the supplier’s payment method suit you (e.g., monthly direct debit)?

Ready to compare energy deals?

Now that you can read your unit rates and standing charges—and calculate a bill—you’re equipped to find a better deal. Compare tariffs for your exact usage and postcode to see your true annual cost, then switch in minutes. Compare energy deals with Cheapest Utility Provider now and start saving.