Electricity Cost Calculator
Estimate your monthly electricity cost based on kWh usage and tariff type.
Last reviewed: Tax year: 2026/2027Source: Eskom — Tariffs and Charges
What changed in 2025 — IBT is gone
Until April 2025, 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.
From 1 April 2025, NERSA approved Eskom’s tariff restructure that removed the IBT entirely for direct Eskom customers. 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.
Eskom Homepower & Homelight rates (April 2026)
| Tariff & supply size | Bundled energy (c/kWh) | Fixed daily charge | Notes |
|---|---|---|---|
| Homepower 1 — Dual-phase 32 kVA / 3-phase 25 kVA | 355.56 | R23.02/day | Small dual-phase or 3-phase residential |
| Homepower 2 — Dual-phase 64 kVA / 3-phase 50 kVA | 355.56 | R42.68/day | Most common residential (larger homes, electric geysers) |
| Homepower 3 — Dual-phase 100 kVA / 3-phase 100 kVA | 355.56 | R84.33/day | High-demand homes (heat pump, pool, large electrical loads) |
| Homepower 4 — Single-phase 16 kVA / 80A | 355.56 | R17.86/day | Small single-phase residential |
| Homelight 20A — Prepaid, low usage (20A supply) | 270.30 | Embedded in energy | Low-income prepaid; Free Basic Electricity (50 kWh) may apply |
| Homelight 60A — Prepaid, larger supply (60A / 80A smart meter) | 343.61 | Embedded in energy | Higher-capacity prepaid; Free Basic Electricity (50 kWh) may apply |
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.
What an average household actually consumes
| Household profile | Without geyser | Electric geyser | Pool + AC |
|---|---|---|---|
| 1 person, small flat | 180 – 300 | 350 – 500 | n/a |
| Couple, 2-bed flat | 300 – 450 | 500 – 700 | 700 – 900 |
| Family of 4, 3-bed house | 500 – 700 | 750 – 1,100 | 1,000 – 1,500 |
| Family of 4-6, 4-bed house | 700 – 1,000 | 1,000 – 1,500 | 1,300 – 2,200 |
Cost per appliance — what’s really driving your bill
| Appliance | Power | Daily use | Monthly cost |
|---|---|---|---|
| Geyser (200L, 3kW) | 3,000W | 4 hours | R1,870 |
| Heat pump (replacement) | 900W | 4 hours | R560 |
| Pool pump | 750W | 8 hours | R935 |
| Aircon (mid-room, ~12,000 BTU) | 1,200W | 4 hours | R750 |
| Tumble dryer | 2,500W | 30 min × 4/wk | R225 |
| Kettle (boil 4× daily) | 2,000W | 12 min | R62 |
| Fridge/freezer (combo) | ~150W avg | 24 hours | R560 |
| LED lighting (whole house) | ~80W avg | 5 hours | R62 |
| Standby (TVs, decoders, chargers) | ~50W avg | 24 hours | R190 |
Worked example — typical Joburg family of 4
3-bedroom house, electric geyser, no pool, Homepower 2 prepaid
850 kWh/month consumption on the NERSA-approved Homepower 2 tariff effective 1 April 2026.
- Monthly consumption
- 850 kWh
- Bundled energy rate (energy + ancillary + network demand)
- 355.56 c/kWh
- Energy cost (850 × 355.56 c/kWh)
- R3,022
- Fixed daily charges (R42.68/day × 30 days)
- R1,280
- Monthly bill
- R4,302
- All-in effective rate (incl. amortised fixed charges)
- R5.06/kWh
- Annual bill
- R51,627
- Geyser share (~50% of consumption)
- R2,150/month
- Switching to heat pump (saves ~70% of geyser cost)
- R1,500/month saving
- Heat pump payback (R30k installed)
- ~20 months
Prepaid vs postpaid — same total, different bill
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.
Free Basic Electricity (FBE) — for low-income households
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.
Cutting your bill — high-leverage interventions
- 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.
How this calculator works
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%.
Sources
Frequently Asked Questions
Eskom uses Inclining Block Tariff (IBT) for homeowners: a low rate for the first block (e.g., 50 kWh/month), a higher rate for the second block, and the highest rate for usage above that.
Homepower is billed monthly. Prepaid requires you to purchase electricity in advance (via a vending machine or online). Prepaid tariff rates differ from monthly billing.
Rates vary by municipality and tariff type. As of 2025, Eskom tariffs are approximately R2.50–R5.00 per kWh depending on your block. Check your municipality's published tariffs.
Use energy-efficient appliances, install solar panels, geyser blankets, LED bulbs, and avoid peak usage if on a time-of-use tariff. Solar is increasingly cost-effective in SA.