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-ihl-series) |
| 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.
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