Electricity Cost Calculator South Africa

Until April 2025, Eskom’s direct residential customers were billed under an Inclining Block Tariff (IBT): the first 350 kWh per month was cheap, the next 250 kWh was more expensive, and consumption above 600 kWh was at a punitive top rate. The structure penalised heavy users and rewarded conservation.

NERSA’s decision of 11 March 2025 approved Eskom’s tariff restructure, which removed the IBT for Homepower and Homelight (Homelight now has a single c/kWh rate), and Eskom implemented it from 1 April 2025. Homepower residential tariffs are now unbundled into six line items: three variable charges (energy, ancillary service, network demand — all in c/kWh) and three fixed daily charges (network capacity, service & administration, generation capacity — all in R/day). Together these make up your bill, and the per-kWh portion is now flat regardless of consumption volume.

This is a structural change. Previously, “the first 350 kWh is cheap” was a real saving for low-volume users. That subsidy is gone; everyone now pays the same per-kWh rate. NERSA’s 2026/27 approval (effective 1 April 2026) pushed slightly more of the bill into fixed charges and slightly less into the per-kWh portion — which raises bills for low-volume users and softens them for heavy consumers.

This applies to customers who buy directly from Eskom. Most urban households buy from their municipality, and municipalities set their own retail tariffs. Some municipalities still use block tariffs: City of Cape Town, for example, publishes a 2026/27 residential schedule with Block 1 up to 600 kWh a month and Block 2 above it (City of Cape Town tariffs). Check your own municipality’s published schedule before assuming a flat rate.

Two different 2026/27 increases. For customers who buy directly from Eskom, NERSA approved an average increase of 8.76% from 1 April 2026. Municipalities buy from Eskom at a separate bulk tariff, which rises 9.01% from 1 July 2026. That 9.01% is what the municipality pays Eskom, not the increase on your municipal bill: each municipality sets its own retail tariff, so the increase you see varies (NERSA media statement).

Most South Africans don’t buy directly from Eskom — they buy from their municipality, which buys bulk from Eskom and resells. Municipal markup adds 5-15% on top of these rates. The City of Cape Town, eThekwini, and Joburg City Power all publish their tariff schedules annually.

One unit of electricity is one kilowatt-hour (kWh). At Eskom’s tariffs effective 1 April 2026, one unit costs R2.70 on Homelight 20A, R3.44 on Homelight 60A and R3.56 on Homepower 2, all including VAT.

How many units does R500 buy? Before fixed charges and vendor fees, R500 buys about 184 units on Homelight 20A, 145 units on Homelight 60A, 140 units on Homepower 2.

Prepaid customers buy electricity in advance via a vendor (FNB, Standard Bank, Capitec, Pick n Pay, EasyPay). The total cost is identical to postpaid — but how the bill is presented differs:

• Prepaid — pay-as-you-use. The three variable c/kWh charges (energy + ancillary + network demand) are bundled into a single rate shown on the meter and vending app. The three fixed daily charges (NCC, S&A, GCC) are still owed — Eskom deducts the monthly fixed total upfront from your first voucher purchase of the month before issuing kWh tokens. You see usage in real time, which makes behavioural change much easier. The downside is no buffer for cashflow shocks.
• Postpaid — billed monthly in arrears. The invoice itemises all six line items separately, which makes audit easier but consumption visibility comes 4-6 weeks after the fact (when behaviour change is harder). Better for cashflow planning, worse for real-time visibility.

Same household, same total cost. The calculator’s “Bill type” toggle is presentation-only; the monthly figure doesn’t change. The bigger lever for your bill is household behaviour and the geyser, not the metering choice.

Households registered as indigent with their municipality receive 50 kWh per month free under the Free Basic Electricity programme. The qualifying threshold is typically a household income under R3,500-R5,500/month (varies by municipality), and registration must be renewed annually.

50 kWh is enough for basic lighting, a small fridge, and a kettle for cooking — not enough for an electric geyser or heater. The intention is a safety net, not a substitute for full-service electricity.

• Geyser timer or heat pump. The single biggest line item in most homes. A R150 timer saves ~R300/month; a R30k heat pump saves ~R1,300-R1,600/month at 2026/27 rates.
• Geyser blanket and pipe insulation. R400 once, saves ~R120/month for a decade. Best return-on-rand of any household efficiency intervention.
• Switch to LED bulbs. Already largely done in most homes; if you still have halogens or incandescents anywhere, replacement pays back in 2-3 months.
• Pool pump scheduling. Run during solar hours if you have panels, or off-peak if you’re on time-of-use tariffs (most prepaid customers aren’t — but worth checking your municipality).
• Standby load audit. A R200 plug-in power meter (Kill-A-Watt equivalent) finds the worst offenders quickly. Old gaming PCs, set-top boxes, and home-office equipment are usual suspects.

Enter your monthly consumption (or appliance usage) and your effective per-kWh rate. The calculator returns daily, monthly, and annual costs, and lets you model before-and-after scenarios for efficiency upgrades.

Your effective rate is on your most recent bill or in your prepaid receipt. If you’re unsure, divide your bill total by units bought (kWh) — that gives the all-in rate including service and network charges. Don’t use the headline c/kWh number alone; it understates the real cost by 10-20%.

• Eskom — Schedule of Standard Prices (effective 1 April 2026)
• Eskom — 2026/27 Tariff Increase landing page
• NERSA — Decision and Reasons for Decision on Eskom Retail Tariff application (11 March 2025)
• Eskom — IBT removal and simplified tariffs from 1 April 2025
• NERSA — ERTSA approval for 2026/27 (media statement, 10 March 2026)
• Eskom — implementation of the NERSA decision for 2026/27
• City of Cape Town — residential electricity tariffs 2026/27
• Free Basic Electricity policy (Notice 1693 of 2003), gov.za