7-1. How to Calculate BCR & FAR for Logistics Facilities
Building Coverage Ratio (BCR) and Floor Area Ratio (FAR) dictate maximum building footprint areas and total allowable gross floor areas relative to site size[cite: 21].
1. How to Calculate Building Coverage Ratio (BCR)
BCR represents the ratio of building footprint area (horizontal projection) relative to total land site area[cite: 21]:
BCR (%) = ( Building Footprint Area ÷ Site Area ) × 100[cite: 21]
-
Overhanging Canopy Rules:[cite: 21]
- If overhanging truck berth canopies project more than 1 meter beyond exterior walls, the portion extending past the 1-meter threshold is included in building footprint calculations[cite: 21].
-
BCR Bonus Exemptions:[cite: 21]
- In 80% designated BCR zones, constructing a fireproof building within a Fire Prevention District grants a 10% BCR bonus (up to 100% no-limit on corner lots)[cite: 21].
2. How to Calculate Floor Area Ratio (FAR)
FAR represents the ratio of cumulative gross floor area across all stories relative to total land site area[cite: 21]:
FAR (%) = ( Gross Floor Area ÷ Site Area ) × 100[cite: 21]
-
Frontage Road Width Restrictions:[cite: 21]
- Maximum FAR is strictly capped by the lesser value between statutory zoning FAR and the frontage road calculation (Frontage Road Width × Industrial Multiplier 0.6)[cite: 21].
3. Statutory FAR Deductions & Exclusions for Logistics Facilities
Under Japanese Building Standard Act exemptions, specific auxiliary spaces qualify for FAR exclusions, maximizing usable warehouse floor area[cite: 21]:
| Exempted Space Category |
Exclusion Rule & Cap |
Logistics Facility Strategic Advantage |
| Truck Berths & Internal Driveways[cite: 21] |
Excluded up to 1/5th of total gross floor area[cite: 21]. |
Excludes truck docks, driveway lanes, and spiral ramps from FAR limits[cite: 21]. |
| Elevator Shaft Voids |
100% excluded across all floor levels[cite: 21]. |
Multiple freight elevator shafts do not consume allowable FAR[cite: 21]. |
| Disaster Relief Storage Rooms |
Excluded up to 1/50th of total gross floor area[cite: 21]. |
Allows BCP emergency storage rooms outside FAR caps[cite: 21]. |
4. Sample Calculation Model
[Model Parameters][cite: 21]
- Site Area: 10,000 m²[cite: 21]
- Designated BCR: 60% / Designated FAR: 200%[cite: 21]
- Truck Berth & Driveway Area: 2,500 m²[cite: 21]
- Building Footprint Area: 6,000 m²[cite: 21]
BCR Verification
6,000 m² ÷ 10,000 m² × 100 = 60% (Within 60% Limit: COMPLIANT)[cite: 21]
FAR Calculation (Applying Berth Exclusion)
With planned gross floor area of 22,000 m² (including 2,500 m² berths)[cite: 21]:
- Max Berth Exclusion Cap = 22,000 m² × 1/5 = 4,400 m²[cite: 21]
- Since 2,500 m² berth area is below the 4,400 m² cap, the full 2,500 m² is excluded. Adjusted FAR Floor Area = 22,000 m² - 2,500 m² = 19,500 m²[cite: 21]
Calculated FAR = 19,500 m² ÷ 10,000 m² × 100 = 195% (Within 200% Limit: COMPLIANT)[cite: 21]