Your electricity budget is not always the same as the amount available to buy kWh. South African prepaid tariffs may include service charges, tax, lifeline allowances and increasing block prices.
First check the tariff
Look at your latest token receipt to identify the actual units received and your effective rate. A simple average is the rand amount actually applied to energy divided by the units received. If R500 goes towards energy and buys 160 kWh, your observed rate is about R3.13 per kWh.
Why the same R500 can buy fewer units
If tariff blocks are based on monthly purchases or consumption, later purchases can fall into higher-priced tiers. Fixed deductions can also reduce the amount allocated to energy. Do not assume each recharge starts a new tariff block.
Try a budget first
Use the prepaid electricity calculator to change rates and fixed deductions. It is an estimate. Use your supplier’s rates and check the result against your receipt.
Read the receipt before trusting the price per unit
The number on a prepaid token may represent the energy credit added to the meter, not every charge associated with the transaction. Depending on your municipality and tariff category, fixed amounts, arrears recovery, levies or taxes may affect what portion of a cash payment becomes units. Where a stepped tariff applies, two purchases of the same rand amount at different points in a billing period can also yield different units.
Keep a record of the amount paid, the kWh received and any deductions shown on each receipt. For a rough effective rate, divide the energy spend by units credited. Repeat over several purchases, since a single receipt may be affected by a block boundary or administrative charge.
Four questions worth asking the supplier
Which tariff category is the meter on? Are there service charges or fixed deductions? When do block quantities reset? Does the quoted price include VAT? The answers let you replace this site's illustrative inputs with your actual local rules.
Municipal tariffs and purchase rules change. The rates in this guide are examples. The separate Cape Town guide and calculator preset identify the source and period for their published rates. Check your own supplier’s tariff schedule and account before using any rate.
Check what happened before and after a block threshold
Imagine an illustrative two-block purchase with the first 100 kWh costing R2.50/kWh and additional units costing R3.50/kWh, with no fixed deduction. R250 buys the entire first 100 kWh. A R500 purchase in the same simplified calculation buys 100 kWh from the first block plus about 71.4 kWh from the second, for roughly 171.4 kWh in total. It would be incorrect to divide the whole R500 by R2.50 and promise 200 kWh.
Real stepped tariffs may depend on cumulative purchases or consumption during a billing period rather than starting at the lowest block each time. Our prepaid calculator lets you enter units already bought this month, along with daily and other charges. It uses those entries to work out how much of the first block remains, but cannot retrieve your purchase history. Use your statement or token receipts to check the inputs.