Electricity Tariff Comparison Calculator
Compare unit rates, standing charges and fixed tariff offers.
How the tariff comparison works
The calculator multiplies your electricity use by the unit rate, adds the daily standing charge for the comparison period, then compares the current tariff with the new tariff. If you enter an exit fee, it is included in the new tariff side as a switching cost.
This makes the comparison clearer than looking at unit rates alone. A tariff with a lower unit rate can still be more expensive if the standing charge is much higher or if the saving is smaller than the exit fee.
What to check before switching
Check whether prices include VAT, whether the offer needs a smart meter, whether direct debit is required, how long the fix lasts, and whether there are exit fees on either tariff. Also check gas separately if you are comparing a dual-fuel deal.
Estimate only. Energy prices, regional standing charges, payment methods, discounts, meter types and tariff terms can change. Use the calculator to compare the numbers shown to you, then check the supplier's final quote before switching.
When this helps most
This is useful when you are comparing a fixed electricity tariff with your current variable rate, checking whether a cheaper unit rate offsets an exit fee, or working out whether a small monthly saving is worth the risk of leaving a flexible tariff.
If your annual usage is unknown, use last year's bill or your supplier app. A rough average can be useful for a first look, but your own kWh figure is much better because electricity use varies widely between homes.
Reading the result
A saving over the comparison period means the new tariff is estimated to cost less for the usage and charges entered. An extra cost means the current tariff is cheaper on those assumptions. The monthly figure is just the period saving divided into average months, not a direct debit prediction.
Standing charges matter more for low-use homes, while unit rates matter more for high-use homes. If your electricity use changes a lot between summer and winter, compare a full year where you can.
Electricity tariff FAQs
Why do I need the standing charge?
The standing charge is paid per day, even when usage is low. A tariff with a cheaper unit rate can still cost more if the standing charge is much higher.
Should I use annual kWh or monthly kWh?
Annual kWh is usually easier for tariff comparisons because it smooths out seasonal changes. Use your own bill or supplier app figure where possible.
Does the calculator include gas?
No. This calculator compares electricity only. Check gas separately if you are comparing a dual-fuel deal.