Finish (Eco / Standard / Premium)
Coefficients 0.88 / 1 / 1.25. Applied mainly to wall m² items and fixed packages; electrics follow a distinct logic (base package + m², without this quality coefficient).
How Kodarch calculates your renovation budget range
The calculator sums the selected work items (paint, flooring, packs…), applies coefficients for finish level, region and property condition, then shows an indicative VAT-inclusive range around a median budget. It is not a contractual quote.
Free to try · optional account to save your projects
The four steps
Step 1
Project type
Kitchen, bathroom, living spaces or whole home: this filters the catalogue of available work items (for example wall tiles and sanitary fittings mainly for bathroom / kitchen).
Step 2
Dimensions and context
Floor area (or length × width), ceiling height, surface condition, region (Greater Paris / Île-de-France or rest of France), occupancy during works, and old floor removal if needed.
Step 3
Finish level
Eco, standard or premium: a coefficient multiplies most work items (eco about −12%, premium about +25% versus standard).
Step 4
Work items to price
Select only what is in scope. Each item has a base (wall m² rate, floor m² rate, fixed package, or electrics package + m²) before coefficients are applied.
From median to range
Once work items are calculated:
- Median budget = sum of amounts for each selected item that applies to the room type
- Low bound = median × 0.9 (about −10%)
- High bound = median × 1.18 (about +18%)
- The UI shows the low–high range with a VAT-inclusive label, plus the median budget
The “VAT-inclusive” label is a product display on euro unit rates: the calculator does not compute VAT separately (10% / 20% rates, etc.).
What really changes the amount
Beyond floor area and selected items, these coefficients apply (depending on item type):
Region
Greater Paris (Île-de-France): +12% (coefficient 1.12). Rest of France: coefficient 1. No finer département-level granularity.
Surface condition
Light (1), medium (+15%), heavy (+35%). Affects walls and fixed packages; floor m² does not use this condition coefficient, but can add €15/m² when removal is selected.
Home occupied during works
If yes: +8% on most items (excluding the specific electrics logic).
Old floor removal
Surcharge of €15 per m² of floor, only if the flooring item is selected and removal is enabled.
Floor area and walls: assumptions
Area-only mode: wall m² are estimated assuming a square room (formula 4 × √area × height).
Length × width mode: walls = 2 × (L + W) × height — walls only, not the ceiling.
“Whole home” mode: combined floor area of zones where selected items apply — not an automatic room-by-room quote for the entire flat.
Openings (doors, windows) are not deducted from wall m² in the budget calculator (unlike the trades materials calculator).
What is not included
For an honest citation of the calculator:
- A firm, signed or customised contractor quote (margins, site conditions)
- A fiscal VAT calculation by rate
- Editor catalogue furniture, designer fees, moving costs
- Out-of-catalogue items (MVHR, complex waterproofing, exterior joinery, separate ceiling paint, etc.)
- Contingencies and site unknowns
Frequently asked questions
Everything you need to know before creating your plan or estimating your renovation budget.
How are the low / high bounds calculated?
The median budget is the sum of selected items after coefficients. The low bound is 90% of that median; the high bound is 118%. Amounts are shown with a VAT-inclusive label, without a separate VAT calculation.
Which parameters really change the amount?
Floor area (and wall estimate), selected work items, finish level (eco / standard / premium), Greater Paris region, surface condition, occupancy during works, and old floor removal (+€15/m² on the flooring item).
Why can wall area differ from my survey?
In area-only mode, Kodarch assumes a square room to estimate walls. In length × width mode, only walls are counted (not the ceiling). Openings are not deducted in this calculator.
Does “whole home” mode price the entire flat?
No. You enter a combined floor area and select the relevant work items. It is not an automatic detailed room-by-room quote.
Why do some work items not appear for every room type?
The catalogue is filtered by project type: for example wall tiles and sanitary fittings mainly for bathroom or kitchen; electrics mainly for living spaces or whole-home mode. Packs may exclude equivalent unit items.
Does the calculator replace a contractor quote?
No. It is an indicative range to frame the project before requesting firm quotes. Amounts remain indicative until validated by a professional.
Go further
Ready to frame your renovation budget?