Floor Area Ratio Calculator, South Africa
Work out your erf's maximum footprint, maximum floor area and the minimum storeys needed to use your full FAR, from your zoning certificate's coverage and FAR figures.
Quick answer: Your zoning certificate or land use scheme sets two separate limits: a coverage percentage capping your ground-floor footprint, and a Floor Area Ratio (FAR, sometimes called bulk) capping total floor area across all storeys. Enter both figures below to see your maximum footprint, maximum floor area, and the minimum storeys needed to use your full FAR allowance.
⚠️ For planning purposes only, not a rezoning or building-plan approval. Confirm your exact coverage and FAR against your own zoning certificate before finalising any design.
How to Use This Calculator
- 1Enter erf sizeEnter your total erf size in square metres. This is the full stand size shown on your title deed or SG diagram.
- 2Enter site coverage allowedEnter the site coverage percentage from your zoning certificate or land use scheme. This field is required.
- 3Enter FAR allowedEnter the Floor Area Ratio, sometimes called bulk, from your zoning certificate or land use scheme. This field is required.
- 4Enter storeys planned (optional)Optionally enter how many storeys you're planning. Leave blank to see the minimum storeys needed to use your full FAR allowance instead.
- 5Click CalculateResults show your maximum footprint, maximum floor area, minimum storeys for full FAR, and which limit governs your build.
Floor Area Ratio and Site Coverage in South Africa: 2026 Guide
Before you can plan how much house, flatlet or extension fits on your erf, you need two figures from your municipality's zoning: your site coverage percentage and your Floor Area Ratio (FAR). Together they set the legal ceiling on what you can build, and mixing them up, or ignoring one in favour of the other, is one of the most common planning mistakes South African homeowners and small developers make before speaking to an architect or town planner. For the full costing and cash-flow picture once your floor area is confirmed, see the Developer's Build Cost Planning Guide.
What Is Floor Area Ratio (FAR)?
Floor Area Ratio (FAR), sometimes called bulk in South African planning practice, is the maximum total floor area you may build across every storey combined, expressed as a multiple of your erf size. A FAR of 0.6 on a 500m² erf allows 300m² of total floor area, spread across as many storeys as your coverage and height limits allow. Build a single-storey 300m² home and you've used your full FAR in one go. Build two storeys of 150m² each and you've used the same 300m², just stacked. FAR is set out in your municipality's land use scheme, the current term for what older documents call a town planning scheme, and confirmed on your zoning certificate for your specific erf.
What Is Site Coverage, and How Is It Different?
Site coverage is the maximum percentage of your erf that a building's footprint may occupy at ground level, on any single floor, while FAR caps total floor area across every storey combined instead. A 500m² erf with 50% coverage allows a 250m² footprint on that floor. Coverage and FAR aren't alternatives to each other. Both apply at the same time, and whichever produces the smaller number for a given design is the one that actually limits you.
How This Calculator Works
Enter your erf size, your coverage percentage and your FAR. The calculator applies both formulas and tells you where they land relative to each other, plus the minimum number of storeys you'd need to use your full FAR allowance without exceeding your coverage footprint on any one floor.
Max Footprint = Erf Size (m²) × Coverage Allowed (%)
Max Floor Area = Erf Size (m²) × FAR Allowed
Min. Storeys for Full FAR = ROUND UP(Max Floor Area ÷ Max Footprint)
Floor Area at N Storeys = MIN(Max Footprint × N, Max Floor Area)
When Coverage Governs, and When FAR Governs
On a single storey, whichever of Max Footprint or Max Floor Area is smaller is the one that actually limits your build. If your coverage footprint is smaller than your FAR floor area, coverage governs on one storey, and you'd need to add storeys to use the rest of your FAR. If your FAR floor area is smaller than your coverage footprint, FAR governs even on one storey, and building out to your full permitted footprint isn't possible without exceeding your FAR. If you enter a number of storeys you're actually planning, the calculator checks that scenario specifically: whether your planned footprint across that many floors stays inside your FAR, or exceeds it.
A Worked Example
Take a hypothetical 450m² erf, coverage allowed at 45% and FAR allowed at 0.5, the kind of figures a typical single-residential zoning certificate might show. Max Footprint works out to 450 × 0.45 = 202.5m² on any one floor. Max Floor Area works out to 450 × 0.5 = 225m² in total across every storey. Since 202.5m² is smaller than 225m², coverage governs a single-storey build, capping you at 202.5m², short of your full 225m² FAR allowance. Dividing 225 by 202.5 and rounding up gives a minimum of 2 storeys to use the full FAR, for example 112.5m² on each of two floors. This example uses round, hypothetical figures for illustration only, not any real erf or municipality's actual zoning. Always confirm your own erf's exact coverage and FAR on your own zoning certificate.
| Figure | Value |
|---|---|
| Erf size | 450m² |
| Coverage allowed | 45% |
| FAR allowed | 0.5 |
| Max footprint (coverage) | 202.5m² |
| Max floor area (FAR) | 225m² |
| Minimum storeys for full FAR | 2 |
Hypothetical figures for illustration only, not any real erf or municipality's actual zoning. The calculator above rounds results to the nearest whole square metre for display, so it would show 203m² rather than the exact 202.5m² worked out here.
Where to Find Your Erf's Coverage and FAR
Your municipality's land use scheme sets coverage and FAR by zone, and your zoning certificate (sometimes called a zoning extract) confirms the exact figures for your specific erf. In Cape Town, the free Zoning Viewer map is a useful first check but is unofficial. The certificate itself is requested through the City's e-Services portal (search "Request Zoning Extract") and is a paid service. In Johannesburg, the Corporate GIS eServices zoning maps are free to view online, though viewing the map isn't the same as holding a formal certificate. Other metros, including Tshwane, Ekurhuleni and eThekwini, run their own equivalent town planning departments. Contact your local municipality's town planning or development management division directly if an online portal isn't available for your area.
What This Calculator Doesn't Tell You
Coverage and FAR are two of the limits on what you can build, not the only ones. Building lines (the minimum distance your structure must sit back from your boundary) and height restrictions apply independently, and can reduce your buildable footprint below what coverage alone would allow, even when your FAR maths works out. Title deed conditions can also restrict development beyond what your zoning permits. Always check your full zoning certificate and title deed before finalising a design. This calculator covers the coverage and FAR maths only. For the full annotated walkthrough of your zoning certificate and SG diagram, see the Zoning Certificate & SG Diagram Guide. Once you know your maximum floor area, estimate what it costs to build with the Building Cost Calculator.