Prepaid Electricity Calculator: How Many Units for Your Rands
Work out how many prepaid electricity units your rands buy on Eskom, Johannesburg, Cape Town, Tshwane, eThekwini and Ekurhuleni tariffs, see how much 100 units costs, and find out why your prepaid runs out so fast. Includes 2026/27 block prices, fixed charges and free basic electricity.
Prepaid Electricity Calculator
See how many units (kWh) your rands really buy, and why the same R500 sometimes buys fewer units. Covers Eskom prepaid and the five big metros, with 2026/27 tariffs, block limits, fixed charges and free basic electricity built in.
It is printed on your token receipt, or divide the rand amount of a recent purchase by the units you received.
Blocks reset on the 1st of every month. Add up the units from this month’s tokens (they are on your receipts). If this is your first purchase of the month, leave it on 0.
We convert it to units at your tariff, allowing for any fixed charges taken from the first purchase.
Cape Town collects the Domestic service charge through the vending system at R2.46 per day since your previous purchase, before any units are issued.
A small flat or cottage is often 250 to 450 kWh, a family home 450 to 900 kWh, and more with geysers, pools or heaters running hard.
How many units does R500 of electricity buy in South Africa?
On the most common tariffs, R500 of prepaid electricity buys roughly 120 to 150 units (kWh) in 2026/27. On Eskom’s direct Homelight 60A tariff it is about 145 units, in Tshwane about 129 on a first purchase, and in Johannesburg only about 77 units on your first purchase of the month, because City Power takes R241.50 in fixed charges out first. The exact number depends on your supplier, your tariff and how much you have already used this month, so put your own amount into the calculator above for a precise answer.
These are ranges because every municipality charges a different rate, and inclining blocks mean a big purchase or a busy month pushes some units into a pricier block. The calculator handles all of that for your own supplier.
How much is 100 units of electricity?
In 2026/27, 100 units (100 kWh) of prepaid electricity costs roughly R340 to R580 on most standard tariffs, VAT included. It is about R344 on Eskom Homelight 60A, R373 in Tshwane, R411 in eThekwini and R576 in Johannesburg once the City Power fixed charges are counted. To turn a number of units into rands for your own tariff, switch the calculator above to My monthly cost and enter the units.
Why does my prepaid electricity run out so fast?
If your units seem to vanish, there are usually three honest reasons before you suspect a faulty meter. First, inclining blocks: your meter’s month-to-date total sets the price of the next unit, so the first units each month are the cheapest and every unit after a block limit costs more. On the 1st of the next month the count resets and you start cheap again. That is why a R500 token on the 2nd buys far more than the same R500 on the 25th. Second, fixed charges: in Johannesburg City Power recovers R241.50 (VAT included) a month through the vending system, so your first purchase delivers fewer units, and in Cape Town the Domestic tariff takes R2.46 for every day since your last purchase off the top of each token. Neither is a vending error, but neither is printed clearly on most receipts. Third, the appliances themselves: geysers, heaters and pool pumps quietly eat units, which is why the tool shows what your units actually run.
When is the cheapest time to buy prepaid electricity?
The price of a unit does not change with the time of day or the day of the week, so there is no daily bargain window. What matters is the calendar month and the yearly increase. Because blocks reset on the 1st, the units you buy early in the month are the cheapest ones you will get that month, so buying a larger amount early keeps more of your spend in the low block. The bigger saving is timing the annual increase: municipal prices rise on 1 July and Eskom on 1 April, and prepaid tokens never expire, so if you are still in a low block in late June it is worth stocking up at the old price.
Three things worth knowing
- Buying in small amounts does not dodge the blocks. Blocks follow your monthly total, not the size of each purchase. Ten R100 tokens cost exactly the same as one R1,000 token in the same month.
- Prices change every July (April for Eskom). If it is late June and you are still in the cheap blocks, stocking up before the increase buys units at the old price. Prepaid tokens do not expire.
- Free basic electricity goes unclaimed by millions of households. If your household is registered as indigent with your municipality, you can claim 50 to 65 free units every month. The token must be collected monthly and does not roll over.
Frequently asked questions
How many units of electricity do I get for R500?
It depends on your supplier, your tariff and how much you have already bought this month, but on a standard tariff R500 buys roughly 120 to 150 units. On Eskom’s Homelight 60A tariff R500 buys about 145 units. In Tshwane a first purchase of the month buys about 129 units, while in Johannesburg a first purchase buys only about 77 units because R241.50 in fixed charges comes off first. Use the calculator above with your own numbers.
How many units does R1,000 of electricity buy?
On a standard 2026/27 tariff, R1,000 buys roughly 240 to 300 units (kWh). It is about 290 units on Eskom Homelight 60A. Because prepaid uses inclining blocks, a single R1,000 purchase can tip some units into a higher-priced block, so a large buy early in the month keeps more of it in the cheap block. The calculator shows the exact split for your supplier.
How much is 100 units of electricity?
About R340 to R580 on most standard tariffs in 2026/27, VAT included: roughly R344 on Eskom Homelight 60A, R373 in Tshwane, R411 in eThekwini and R576 in Johannesburg once City Power’s monthly fixed charges are counted. Switch the calculator to the monthly cost mode and enter 100 units to see the figure for your own tariff.
Why does my prepaid electricity run out so fast?
Usually one of three things, not a broken meter. Inclining blocks make every unit after a monthly limit more expensive, so later purchases buy fewer units. Fixed charges are taken out of your token in some metros (R241.50 a month in Johannesburg, a daily charge in Cape Town). And heavy appliances like geysers, heaters and pool pumps use far more than people expect. The calculator shows all three, including what your units actually run.
When is the cheapest time to buy prepaid electricity?
The unit price does not change by time of day, so there is no daily window. Blocks reset on the 1st, so units bought early in the month are the cheapest that month. The real saving is the yearly increase: prices rise on 1 July for municipalities and 1 April for Eskom, and tokens never expire, so stocking up in late June at the old price can pay off.
Why did my first purchase of the month give me fewer units?
Some municipalities recover fixed monthly charges through the prepaid vending system. City Power in Johannesburg takes its service and network capacity charges out of your purchases each month, and Cape Town’s Domestic tariff deducts a daily service charge for the days since your last purchase. The rest of your money then buys units as normal.
Do I get more units if I buy electricity in small amounts?
No. Block tariffs work on your total units for the calendar month, not per purchase. Splitting purchases changes nothing about the price. The only timing that matters is the annual price increase: units bought in late June are charged at the old year’s rate.
What is free basic electricity and how do I claim it?
Free basic electricity (FBE) is a government subsidy of roughly 50 free units per month (60 in some Cape Town cases and 65 in eThekwini) for households registered as indigent with their municipality. Register at your municipal office, then collect the free token every month from your usual vendor by buying for R0 or using the FBE option. It cannot be accumulated: skip a month and those units are gone.
When do prepaid electricity prices change?
Municipal tariffs change on 1 July each year after NERSA approval. Eskom direct tariffs change on 1 April. This calculator uses 2026/27 rates, VAT included, from each supplier’s official tariff schedule.
Rates used and sources
Estimates only, based on official published tariffs including VAT. Vendor rounding, arrears collections on the meter and municipal surcharges can change what a specific token delivers. Figures marked provisional await the supplier’s final 2026/27 publication. Try our Solar Savings Calculator to see what part of this bill solar could remove, or browse all our free tools and calculators.