Power Plan Comparison Calculator NZ

This calculator helps you work out which of two New Zealand power plans is actually cheaper for your household, based on how much electricity you really use rather than which plan has the flashiest headline rate. Power companies price plans using two parts: a daily fixed charge, billed whether you use power or not, and a per-unit rate charged for every kilowatt-hour you consume. A plan that looks cheap on the unit rate can still cost more overall if its daily charge is high, and that trap catches out a lot of switchers. You enter your typical daily usage in kilowatt-hours, then the daily charge and per-unit rate for Plan A and Plan B, both in cents to match how your power bill is presented. The calculator works out the full annual cost of each plan by multiplying the daily charge by 365 and adding the unit rate multiplied by your annual usage, then tells you which plan wins for your usage, the annual cost of each, and the dollar saving between them. Use it whenever you are comparing offers from different retailers or deciding between a low-user and standard-user plan, since the daily charge differs between those categories. It ignores prompt-payment discounts and GST timing differences, which vary by retailer, so treat the result as a solid estimate rather than an exact bill forecast.

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Plan A

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Plan B

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Plan A is cheaper for you
cheaper plan for your usage (annual cost)
Plan A per year$2,091
Plan B per year$2,307
Saving$215

Charges are entered in cents to match power bills. Low-user and standard-user plans differ in their daily charge, so check which category fits your usage. This ignores prompt-payment discounts and GST nuances, which vary by retailer. Estimate only, not financial advice.

How it works

Each plan cost is the daily fixed charge times 365, plus the per-unit rate times your annual usage. Your annual usage is your daily kWh times 365. The calculator adds the fixed and usage parts for each plan and compares the totals. A plan with a low unit rate but a high daily charge can lose to one with a higher unit rate but a low daily charge, especially for lighter users, which is exactly the trap this tool reveals.

Worked example

Using 18 kWh a day, Plan A at a 69 cent daily charge and 28 cents a unit costs about $2,090 a year. Plan B at a 200 cent daily charge but 24 cents a unit costs about $2,307. Despite Plan B lower unit rate, Plan A wins here because of its much lower daily charge.

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Frequently asked questions

How do I compare power plans in New Zealand?

Compare the daily fixed charge and the per-unit rate together against your actual usage. A plan with a low unit rate but a high daily charge can cost more overall, especially if you use less power.

What is a daily fixed charge?

It is a set amount you pay each day regardless of how much power you use, on top of the per-unit rate. Low-user plans have a lower daily charge, which can suit smaller households.

Why does my usage matter when comparing plans?

The cheapest plan depends on how much power you use. Heavy users benefit most from a low unit rate, while light users benefit more from a low daily charge. The calculator compares plans for your actual usage.