Why R500 sometimes buys fewer prepaid units?

You buy R500 of electricity, punch in the token and stare at the kWh because the number looks wrong. Same money, fewer units than last time. Before blaming the meter, look at the tariff attached to your supply because R500 does not represent a fixed amount of electricity.

R500 buys electricity at your current rate

Prepaid electricity is sold in kilowatt-hours, or kWh, at a rate per unit. If electricity costs R3 per kWh, R500 buys about 166.7 kWh before any applicable charges. At R3.50 per kWh, the same R500 buys about 142.9 kWh.

Your supplier and tariff category affect the calculation. NERSA publishes separate 2026/27 municipal tariff decisions for electricity distributors around South Africa, while Eskom direct customers fall under Eskom tariffs.

R500 is a rand amount, not a fixed bundle of electricity. Once the rate attached to each kWh changes, the same purchase gives you fewer units even though the amount leaving your bank account has not changed.

Your monthly purchases could affect the rate

Some municipal prepaid tariffs use blocks, which charge a higher rate after a household passes a set number of kWh during the month. Splitting one purchase into several smaller ones does not necessarily dodge the next block because the meter account records the monthly purchase total.

Check the rate and kWh printed on each token or receipt. Comparing those figures with an earlier purchase is far more informative than comparing the R500 amount alone.

Check what was deducted before the units

Certain prepaid tariff structures include fixed service charges, which means part of a purchase could go towards charges before the rest converts into electricity. Your supplier, tariff category and local pricing structure determine whether this applies.

Households that qualify for free basic electricity receive an allocation under municipal rules, separate from electricity bought with household money. Knowing which tariff and benefits apply to your meter makes monthly comparisons far less confusing.

Does your household qualifies for free electricity?

A monthly electricity allocation is available to qualifying South African households, but eligibility is handled at municipal level. Knowing where to check can save you from relying on assumptions about income or meter type.

Flip the MarketLiz Thorne

Two R500 purchases do not automatically equal the same kWh. Check the tariff, monthly purchase total and any deductions when the units look lower than expected. Your token gives you the numbers needed to work out what changed.