Tools · Warehouse planning

High bay lighting calculator

How many high bay lights do you need? Start with floor area, a target light level and published fixture lumens. Check the estimate with a photometric layout before bidding.

Estimate your fixture count

Default assumptions: 20 foot-candles (fc), coefficient of utilization 0.60 and light-loss factor 0.80. Change these to match your project criteria.

Interactive calculation needs JavaScript. Use the formula and worked examples below to calculate by hand, then request a photometric layout.

Dimension unitsFloor length (ft)Floor width (ft)Fixture height above floor (ft)Space typeTarget foot-candles (fc)Coefficient of utilization (CU)Light-loss factor (LLF)

Fixture model, wattage and published output

UHB26 and FLS21 use published maximum output at maximum wattage only. Lower-setting lumens are not published. MLH06 pairs each wattage with 4000 K or 5000 K output.

Typical planning range: 10–30 fc for warehouse aisle storage. These are general planning references, not code requirements. Changing space type resets the target; you can edit it.

Height goes into your layout request. It does not change this average lumen calculation. Optics, task height and obstructions need a photometric model.

CU estimates the fraction of light reaching the calculation plane. LLF allows for reduced output and dirt. Both defaults are teaching assumptions, not measured room values.

Planning estimate

For a 100 × 100 ft warehouse aisle storage space at 20 fc, estimate 27 fixtures and 2,700 W total.

Estimate for the displayed inputs
Fixtures needed (rounded up)	27
Approximate spacing	19.2 ft
Total fixture watts	2,700 W
Published lumens per fixture	16,000 lm
Floor area	10,000 ft²

UHB26-060/080/100CDM-3050L13J · 100 W · published maximum · CU 0.60 · LLF 0.80 · mounting height 20 ft.

Check the selected fixture’s published data.

Approximate spacing = √(floor area ÷ fixture count). This is an equivalent square spacing, not a row layout or a permitted spacing limit. Room shape, racks and optics can require different placement or more fixtures.

Planning estimate only. A photometric layout from IES files is needed for a bid — request one.

Send rack positions, task heights, surface conditions, voltage and required uniformity with your plan. The form carries your current estimate into RFQ after calculation.

The lumen method

Fixtures = round up [(target fc × floor area in ft²) ÷ (fixture lumens × CU × LLF)].

Total watts = rounded fixture count × selected fixture watts. For metric dimensions, area in ft² = area in m² ÷ 0.09290304. Targets remain in foot-candles.

This estimates average maintained illumination. It does not calculate minimum values, rack-face light, glare or uniformity. Height affects the real distribution and utilization; the calculator cannot infer those effects.

Worked example from the warehouse guide

The first two rows use a hypothetical 20,000-lumen fixture. It is a teaching input, not an Allmax model or a selectable product.

10,000 ft² at 20 fc, with LLF 0.80 in every row
Example	Lumens	CU	Calculation	Fixtures
Guide teaching example	20,000	0.60	200,000 ÷ 9,600 = 20.83	21
Guide sensitivity example	20,000	0.50	200,000 ÷ 8,000 = 25	25
UHB26-060/080/100CDM-3050L13J, 100 W maximum	16,000	0.60	200,000 ÷ 7,680 = 26.04	27

The published-fixture example totals 2,700 W with approximate square spacing of 19.2 ft. Read the warehouse lumen-method guide and high-bay mounting-height guide before using the result for planning.

Typical planning ranges

These IES-style general references help start a discussion. They are not code requirements or universal targets. Confirm the actual task and calculation plane with the designer.

Starting references in foot-candles; editable targets, not project specifications
Space type	Typical planning range	Scope
Warehouse aisle storage	10–30 fc	Check rack faces and label size separately.
Open warehouse	10–30 fc	Separate picking and packing tasks from bulk storage.
Manufacturing	30–50 fc	General work only; detailed inspection needs its own criteria.
Gym	50–100 fc	School/college gym reference; sport, competition and viewing conditions govern.
Retail	20–50 fc	High-activity circulation to merchandise areas; display accents are separate.

Sources: Teamsters warehouse guidance gives older IES-based 10 and 30 fc task examples. The RTX energy guide, page 44 gives a 30–50 fc manufacturing reference attributed to IES.

The Commercial Energy Library’s gym guidance discusses 50–100 fc for high-school and college gyms. LADWP retail guidance distinguishes 20 fc circulation and 50 fc merchandise areas in high-activity spaces.

These sources describe different tasks and contexts. They do not establish suitability of any fixture. The IES Illuminance Selector FAQ explains why the actual task surface matters.

Published fixture data: UHB26, FLS21, MLH06 130–210 W, and MLH06 300 W. No lumen values are interpolated.

Next step

Price a job, or ask for the documents.

IES files and listing file numbers travel with the quotation.

Request a quote