Free engineering tool
High bay lighting calculator
How many LED high bays does your warehouse, factory or sports hall need? Enter the hall size, mounting height and target light level to get the number of fixtures, a layout grid, the spacing check and the power density.
Method
The calculator uses the lumen method from lighting design practice: N = E × A ÷ (Φ × UF × MF). The utilisation factor (UF) depends on the room index K = L × W ÷ (Hm × (L + W)), where Hm is the height of the luminaire above the working plane, on the beam angle and on how much light the ceiling, walls and floor reflect.
The number is then arranged in a grid, and the grid is checked against the maximum spacing for the beam angle, so the light is even and not just high on average. When spacing forces more fixtures than the light level needs, the calculator suggests a lower wattage per fixture.
Worked example
A 60 × 30 m warehouse, 10 m mounting height, 200 lx, 150 W high bays at 130 lm/W with 90° beams: Hm = 9.2 m, K ≈ 2.2, UF ≈ 0.67. N = 200 × 1,800 ÷ (19,500 × 0.67 × 0.8) ≈ 35. Arranged to the hall’s proportions this becomes an 8 × 5 grid of 40 fixtures at 7.5 × 6 m, well inside the 11 m spacing limit (1.2 × 9.2 m), for about 230 lx average.
Questions about this calculation
How many lux does a warehouse need?
EN 12464-1 recommends about 100 lx for storage areas, 150 lx where people pick goods, 200 lx for loading bays and rough work, 300 lx for workshops and assembly, and 500 lx for fine assembly and inspection. Local codes and client standards may require more.
How far apart should high bay lights be?
Spacing should not exceed about 1.5 × the mounting height for wide 120° beams, 1.2 × for 90° and 0.9 × for 60° narrow beams. Wider spacing leaves dark patches between fixtures even when the average lux is high.
Which beam angle should I choose?
Use 90°–120° in open halls with mounting heights up to about 10 m, 60°–90° for 10–15 m, and narrow beams (30°–60°) for very high ceilings and racking aisles, where the light must reach the floor between tall racks.
What is the maintenance factor?
It accounts for light lost over time from LED depreciation and dirt on the luminaire. 0.8 is typical for LED high bays in clean halls; use 0.7 in dusty plants such as foundries and cement works.
More free tools
- Solar street light calculatorBattery Wh / Ah and solar panel watts from LED power, schedule, sun hours and autonomy.
- Street light pole height & spacing calculatorRecommended pole arrangement and maximum spacing from road width, pole height and LED lumens.
- Solar battery autonomy & rainy-day calculatorHow many rainy days your solar street light battery lasts, and whether it survives your rainy season.
- Solar vs grid street lighting cost calculatorTotal cost of ownership over 5–25 years: trenching, cabling and electricity vs. solar street lights.
- LED retrofit energy savings & payback calculatorEnergy, money and CO2 saved by replacing sodium, metal halide or fluorescent lights with LED.
Next step
Ask our engineers to check your design
Calculators give planning figures. Send us the site location, drawings and quantity, and we return a photometric or solar sizing check and a quotation for the complete set.
Email us
[email protected]Tell us the product, quantity, site location and any drawings or specifications. An engineer reads every email and we reply within one working day (China time, GMT+8).