Short answer
Two coefficients, two questions: how much ground the building may cover, how much floor area it may total
A zone regulation limits construction through two ratios to the plot’s area: one caps the ground footprint, the share of the parcel the building may cover; the other caps the total floor area, all levels added. Together with the maximum height and the setbacks, they draw the buildable volume. The abbreviations used for them, COS and CUS, are not applied in the same sense by every regulation or every source; the only reliable reading is the definition written in the zone regulation, which the planning information note attaches as an extract.
“My plot is 400 m², how much can I build?” The answer is never a single number: it depends on a footprint coefficient, a floor-area coefficient, a height, setbacks, and sometimes subdivision specifications that tighten things further. This guide explains what each coefficient measures, why their names cause confusion, how they combine with height and setbacks, and how to do the calculation on an example. It draws on the general building regulation and on definitions published by the specialist press, and refers to the guide on planning documents.
What do the two coefficients measure?
In brief
One relates the built area on the ground to the plot’s area; the other relates the total floor area to the same area. The first draws the imprint, the second the density.
Article 8 of the general building regulation requires the planning information note to state “the maximum site coverage and land-use possibilities”. The phrase covers two distinct limits. The first is a footprint limit: the building’s projection on the ground, external walls included, may not exceed a fraction of the parcel. The second is a volume limit: the sum of the floor areas of all levels may not exceed a multiple of the parcel. A plot may have a low permitted footprint and a high permitted density, which forces a narrow, tall building; or the reverse, which forces a low, spread-out one.
Médias24 states the distinction in plain terms: one coefficient “defines the number of m² you may build on your plot” and “takes the height of buildings into account”, the other “defines the building’s footprint on your plot, a bit like an imprint”. Remember the two questions rather than the two abbreviations: how much ground, how much floor.
Why do COS and CUS cause confusion?
In brief
Because Moroccan regulations, professional sources and French usage do not always give the same abbreviation to the same notion. Read the definition, not the acronym.
In the Médias24 article cited above, “COS” (coefficient d’occupation du sol) is the coefficient giving the buildable floor area and “CUS” (coefficient d’utilisation du sol) the one giving the ground footprint. Other Moroccan professional sources call the footprint a “CES” (coefficient d’emprise au sol) and reserve “COS” for floor area, and some development-plan regulations define their own abbreviations differently. In France, “COS” meant floor-area density and “CES” footprint, which feeds the confusion among French-speaking readers. English-speaking readers add a third layer: “floor area ratio” and “site coverage” are the familiar concepts, but neither appears on a Moroccan planning note. In the texts we were able to read, there is no single mandatory national definition of the abbreviations.
Watch out
Never calculate a buildable potential from an abbreviation read on a listing or a website. Request the planning information note, open the extract of the zone regulation attached to it, and read the definition that regulation gives each coefficient. That definition, and it alone, is what the review committee will apply.
How do height and setbacks enter the calculation?
In brief
Height caps the number of levels; setbacks reduce the ground area available; the floor-area coefficient caps the total. The most restrictive of the three wins.
The planning note states, besides the coefficients, “the conditions of implantation of buildings relative to separating or party boundaries” and “the maximum height of buildings” (article 8). These rules combine. Setbacks from the road and the boundaries define a buildable rectangle inside the parcel; the permitted footprint may be smaller than that rectangle, in which case the footprint governs, or larger, in which case the setbacks do. The maximum height, expressed in metres or in levels (R+2 for ground plus two, R+3 for ground plus three), gives the possible number of storeys; multiplied by the footprint it gives a theoretical floor area, which the floor-area coefficient then caps. The general building regulation itself uses height as a procedural criterion: individual dwellings up to 11.50 m (R+2) in an accepted subdivision fall under the small-projects procedure.
A new alignment, shown on the note as “a new alignment is to be respected along road … of … m width”, removes a strip of the parcel before any calculation: the coefficients apply to what remains, and setbacks are measured from the new line.
How do you do the calculation on an example?
In brief
A fictitious example, for method only: a 400 m² parcel, maximum footprint 0.5, maximum floor area 1.2, height R+2, setbacks of 4 m on the street and 3 m on the other boundaries. Result: at most 480 m² of floor area, and the setbacks bite first.
The values below are invented for the demonstration; real coefficients are read in your zone’s regulation.
| Step | Rule | Calculation | Result |
|---|---|---|---|
| 1. Rectangle after setbacks | 4 m on the street, 3 m on the three other boundaries | (20 − 4 − 3) × (20 − 3 − 3) | 13 × 14 = 182 m² |
| 2. Permitted footprint | Footprint coefficient 0.5 | 400 × 0.5 | 200 m² |
| 3. Actual footprint | The smaller of the two | min(182; 200) | 182 m² |
| 4. Floor area by height | R+2, i.e. three levels | 182 × 3 | 546 m² |
| 5. Permitted floor area | Floor-area coefficient 1.2 | 400 × 1.2 | 480 m² |
| 6. Actual floor area | The smaller of the two | min(546; 480) | 480 m² |
Three lessons. On a small parcel, setbacks are often more restrictive than the footprint coefficient: here they cut the footprint from 200 to 182 m². The floor-area coefficient then caps what the height would allow: 480 m² instead of 546. So the top level will be partial, or the building less spread out than permitted. An architect will do this calculation with the regulation’s exact definitions, which specify what counts in floor area: basements, terraces, plant rooms and balconies are treated differently from one regulation to another.
What do subdivision specifications change?
In brief
They may be stricter than the plan d’aménagement: footprint, height, setbacks, appearance. In a subdivision, they apply on top of the plan.
Médias24 recalls that a lot buyer is “bound to respect the subdivision’s specifications, which will detail all the planning elements required”. The specifications (cahier des charges), annexed to the subdivision permit issued under Law 25-90, often set setbacks, a height or a footprint lower than the zone’s, and sometimes appearance rules. They cannot be more permissive than the plan d’aménagement; they can be more restrictive. Ask the seller or the developer for them before you draw.
Why do small plots lose more than others?
In brief
Because setbacks are fixed in metres while coefficients are proportional: the smaller the plot, the larger the share the setbacks eat before any coefficient applies.
In the example above, the setbacks cost 218 m² out of 400, more than half, before the footprint coefficient came into play. On a 1,000 m² plot with the same setbacks they would have cost about a third. That is why narrow-fronted plots, or plots hemmed in by three side boundaries, lose most, and why they are the ones most often overpriced on the strength of “400 m² buildable” when the real volume is far smaller. Before negotiating the price, run this rough calculation yourself with the coefficients and setbacks on the planning note: the figure you get is what you are actually buying, not the area on the title.
Which errors recur most?
In brief
Confusing footprint and floor area, forgetting setbacks and alignment, counting the basement or terraces without reading the regulation, and reasoning on an outdated note.
- Multiplying the area by a coefficient read on a listing, without knowing whether it is footprint or floor area.
- Forgetting that a new alignment removes a strip of land before any calculation.
- Applying the coefficients to the fenced area rather than to the title’s or the survey’s.
- Counting basements, terraces, garages or plant rooms as if they were always excluded, or always included, when each regulation decides.
- Reasoning on an old planning note: Médias24 recommends a note less than six months old, plans being updated periodically.
- Counting on a derogation to exceed a coefficient. An excess found afterwards exposes you to regularisation, where possible, or partial demolition.
When to consult a professional
The final calculation belongs to the architect
This guide gives the method; the binding calculation is done with the zone regulation’s definitions, which an architect registered with the Order reads fluently. Consult him with the planning note, the regulation extract and, where relevant, the subdivision specifications, before buying the plot and not after. A surveyor registered with the Order supplies the actual area and boundaries to which the coefficients apply.
Does COS mean ground footprint or floor area?
Depending on the source and the regulation, either. Médias24, for instance, reserves “COS” for floor area and “CUS” for footprint; other sources do the reverse or use “CES” for footprint. Read the definition written in your zone’s regulation.
Where do I find my parcel’s coefficients?
In the planning information note issued by the urban agency, which states the maximum site coverage and land-use possibilities and attaches an extract of the zone regulation (article 8 of the general building regulation and the annexed template).
Do basements and terraces count in the floor area?
It depends on how the applicable regulation defines floor area. There is no single rule; it is a point to check with the architect.
Can a coefficient be exceeded by derogation?
A planning derogation is an exceptional procedure before a committee; its outcome is never guaranteed. A project should not be designed in reliance on it.
What happens if the building exceeds the permitted coefficient?
The excess is an offence under Law 66-12; depending on the case, regularisation may be requested, otherwise compliance works or partial demolition follow.
Sources
- Kingdom of Morocco (2013). Decree 2-13-424 of 24 May 2013 approving the general building regulation, article 8, annexes 1 and 3. Bulletin officiel 6174 of 1 August 2013, reproduced by FAOLEX. https://faolex.fao.org/docs/pdf/mor134797.pdf
- Aboulfaraj, Z. (2025). De la carte au terrain : que cache un plan d’aménagement urbain ? Médias24, 9 October 2025. https://medias24.com/2025/10/09/de-la-carte-au-terrain-que-cache-un-plan-damenagement-urbain/
- Aboulfaraj, Z. (2025). Comment obtenir un permis de construire au Maroc ? Médias24, 24 May 2025. https://medias24.com/2025/05/24/comment-obtenir-permis-construire-maroc/