How to calculate the cost of a tariff


| Reading time 2 minutes

The most frequent question we get is “What is the easiest way to calculate the cost of a tariff?”

EDIT: As of October 2017 this continues to be a popular blog post. However, in the 6 years since we first published this, we have moved on quite a bit. We recommend reviewing out developer website, and in particular looking at some of our various calculators (here, here and here)! 

Great question.  There are three ways, in descending order of effort (it would be ascending but we’re not fully quite ready with the third option.):

1) Option 1: using the Tariff data You can get a tariff and all of its rates via the Tariff method. The rate structure includes time of use and holidays and seasons so you can effectively account for all the times of when the electricity was used.  To get an accurate calculation you would need to separate out your usage numbers into the right buckets, such ‘On Peak’ usage, ‘Off Peak’ usage, etc.

Each of the time of use periods have their own rates so once the buckets are filled with accurate usage numbers the calculation will return accurate numbers.

2) Option 2: using the Price method The Price method gives the real time price of a Tariff, and also gives the changes in price over a period of time.  When you call the Price method on a tariff for a given date range it will show you the price of this tariff throughout the date range.  For example, if you’re calculating June 1 - June 30, the first price could be $.06/kWh at 12 a.m. on 6/1.  Then the price would change to $.10/kWh at 2 p.m. on 6/1, then back to $.06 at 8 p.m.   And so on, till the end of the month.  You can sum up your usage data into these buckets to get a total cost.

3) Option 3: using the Genability Calculator This is by far the easiest option.  The calculator takes in actual usage data such as what you would get from a meter reading and calculates the cost of a tariff.  It can also take aggregated usage data, e.g. 1000 kWh for a month, but this will result in a less accurate result. Using the calculator you can essentially reconstruct an entire bill using the Genability Calculator.

The calculator is currently in private alpha and we’re opening it up to people to start trying out.  If would like to try it out or would like to learn more please send us a mail at  We’d love to have you onboard.

As always, you can find documentation for all of our APIs here.

Cash Register

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