How many prepaid units can I get after fees and block tariffs?

How it works

Understand the estimate

First subtract the other charges you entered and any daily charge multiplied by the number of days. The remaining money buys units at the first-block rate until the unused part of that monthly block runs out, then at the later-block rate. For example, a R500 recharge with no fee at R2.80/kWh for the first 350 kWh buys about 178.6 kWh if no units have already been bought that month.

Make it more accurate

Enter the units you have already bought in the month. That reduces how many first-block units remain. If your supplier recovers a daily service charge when you top up, enter its rate and the days since your last purchase. Otherwise leave both at zero.

The standard inputs are illustrative, not current market rates. The optional Cape Town Domestic 2026/27 example uses published City prices for customers on that tariff. Other suppliers and tariffs are different.

Why R500 buys different amounts of electricity

Prepaid electricity can use increasing monthly tariff blocks. A fee can also reduce the amount that buys energy. Our calculator includes previous monthly purchases, but it cannot check your meter, outstanding debt, free basic units or actual transaction history.

Example: Imagine R500 is available for electricity, R40 is deducted in charges, the first 100 kWh costs R2.50 each, and subsequent units cost R3.50. The first block uses R250; the remaining R210 buys another 60 kWh. The total is 160 kWh, not 200 kWh.

Before relying on the estimate

Check which fees were deducted and whether the energy rate includes VAT. Keep a few token receipts to compare the estimate with your purchases.

Read our Cape Town R500 electricity guide for the official 2026/27 example or see the City of Cape Town tariff schedule. For another provider, use its published rates and check your token receipt.

For how our examples work, see our methodology.