LED High Bay Spacing Calculator: How Many Fixtures for Your Warehouse?
Calculate LED high bay spacing and quantity for your warehouse. Rules of thumb by ceiling height, foot-candle requirements, and IES recommendations.
How to Calculate LED High Bay Spacing
The right number of high bay fixtures depends on three things: ceiling height, desired light level (foot-candles), and fixture lumen output.
Quick Rule of Thumb
Spacing-to-mounting-height ratio: High bays should be spaced at 1.0-1.5× the mounting height apart.| Ceiling Height | Recommended Wattage | Spacing | Coverage per Fixture |
|---|---|---|---|
| 15-20 ft | 100W (15,000 lm) | 15-20 ft | 225-400 sq ft |
| 20-25 ft | 150W (22,500 lm) | 18-22 ft | 324-484 sq ft |
| 25-30 ft | 200W (30,000 lm) | 20-25 ft | 400-625 sq ft |
| 30-40 ft | 240W (36,000 lm) | 22-28 ft | 484-784 sq ft |
Foot-Candle Requirements by Application
| Space Type | IES Recommended | Auvolar Fixture |
|---|---|---|
| General warehouse | 20-30 fc | [UFO High Bay 150W](/p/ufo-high-bay-light-hba-series) |
| Warehouse aisles | 30-50 fc | [Linear High Bay 220W](/p/linear-high-bay-light-a-lhb-nv-hv-xk-02) |
| Manufacturing | 50-75 fc | [UFO High Bay 200W](/p/ufo-high-bay-light-hba-series) |
| Detailed assembly | 75-100 fc | UFO High Bay 240W |
| Loading dock | 30-50 fc | UFO High Bay 150W |
Formula: Number of Fixtures
Fixtures = (Area × Target FC) ÷ (Lumens per Fixture × CU × LLF)Where:
- Area = floor area in sq ft
- Target FC = desired foot-candles
- CU = Coefficient of Utilization (0.6-0.8 for typical warehouse)
- LLF = Light Loss Factor (0.85-0.90 for LED)
Example: 50,000 sq ft Warehouse, 25ft Ceiling
- Target: 30 foot-candles (general warehousing)
- Fixture: [UFO High Bay 150W](/p/ufo-high-bay-light-hba-series) — 22,500 lumens
- CU: 0.70 | LLF: 0.88
Fixtures = (50,000 × 30) ÷ (22,500 × 0.70 × 0.88) = 108 fixtures
Grid: ~10 rows × 11 columns, spaced ~21ft × ~22ft
Cost estimate: 108 × $85 = $9,180 + installation Annual savings vs 400W HID: ~$9,200/yearPro Tips
Free Professional Layout
Skip the math — we do it for free. Send us your warehouse dimensions, ceiling height, and racking layout, and our engineers will create a professional photometric layout showing:
- Exact fixture placement
- Foot-candle levels at floor level
- Uniformity ratios
- Fixture quantities and spacing
FAQ
Q: UFO or Linear high bay?A: UFO for open areas, linear for narrow aisles between racking. See our [comparison guide](/blog/ufo-vs-linear-high-bay-comparison).
Q: Should I add motion sensors?A: If any area sees less than 50% occupancy, absolutely. ROI on sensors is typically 3-6 months.
Need Help With Your Lighting Project?
Auvolar provides free lighting design, photometric layouts, and rebate assistance for commercial projects.
Auvolar Engineering Team
City of Industry, California
Our engineering team has 15+ years of combined experience in commercial LED lighting design, photometric analysis, and energy-efficient building systems. We hold DLC QPL listing expertise and work directly with California utilities on rebate qualification. All technical content is reviewed by licensed electrical engineers.