Lighting Design Calculator
How many lights do I need in a room?
Use this free room lighting calculator to estimate how many light fittings you need based on room size, target lux levels, luminaire output, spacing and annual energy use.
1. Room and target brightness
2. Room size
3. Luminaire choice
4. Energy settings
Estimated lighting layout
This quick calculator gives an early-stage estimate for fitting quantity, spacing and annual energy use. For compliance-led projects, use full photometric design software and verified IES/LDT files.
What this room lighting calculator does
This calculator helps you estimate how many light fittings you may need in a room using room area, target lux, maintenance factor and luminaire output. It is useful for early-stage lighting design, budgeting and comparing fixture types before moving into a full lighting design package.
If you are trying to work out how many LED panels, downlights or linear lights you need for an office, classroom, warehouse or meeting room, this gives you a practical starting point. It also estimates annual energy use and running cost so you can compare efficient LED luminaires more easily.
FAQs
How many lights do I need in a room?
That depends on room size, target lux level, fitting output, mounting height, reflectance and spacing. This calculator combines those inputs to estimate the number of fittings needed.
What is lux in lighting?
Lux is the amount of light falling on a surface. Different applications need different lux levels. Offices often need around 500 lux, while corridors may only need around 100 to 200 lux.
Can this replace a full lighting design?
No. This is a quick planning tool. A full lighting design should use real photometric files, detailed mounting conditions, glare checks, emergency requirements and project-specific standards.
How to Work Out How Many Lights You Need
The number of lights you need depends on three simple things:
1. Room size
Bigger rooms need more light. The calculator uses your room length and width to work out the total area.
2. How bright you want the room
Different rooms need different brightness levels:
| Room Type | Recommended Brightness |
|---|---|
| Living room | 100–300 lux |
| Bedroom | 100–200 lux |
| Kitchen | 300–500 lux |
| Bathroom | 200–400 lux |
| Hallways | 100–150 lux |
If you’re unsure, the presets will guide you.
3. Type of light fitting
Not all lights are the same. A high-output LED will cover more space than a low-output one.
For example:
- LED downlights (spotlights) are common in kitchens and bathrooms
- ceiling lights or pendants are often used in living rooms and bedrooms
- LED panels or linear lights are sometimes used in home offices
You can explore different options on our lighting products page depending on the look you’re going for.
How This Lighting Calculator Works
Instead of guessing, this tool does the maths for you.
It:
- calculates your room area
- applies your chosen brightness level (lux)
- factors in light output per fitting
- estimates how many lights you need
It then shows you:
- total number of lights
- suggested layout (rows and spacing)
- predicted brightness
- estimated energy use and running cost
So instead of asking “how many spotlights do I need?”, you get a clear answer in seconds.
How Many Downlights Do I Need in a Kitchen?
This is one of the most common questions.
For a typical kitchen:
- you’ll usually need 1 downlight per 1.5–2 m²
- spacing is typically 1–1.5 metres apart
But this depends on:
- ceiling height
- light output
- layout (island, units, open-plan etc.)
This calculator gives you a more accurate answer based on your exact room size instead of relying on rough rules.
If you’re planning a full kitchen scheme, it’s worth thinking about:
- task lighting (worktops)
- ambient lighting (general brightness)
- feature lighting (islands or dining areas)
How Many Spotlights Per m²?
A common rule of thumb is:
- 1 spotlight per 1.5–2 m² for general lighting
But this can vary depending on:
- beam angle
- ceiling height
- brightness (lumens)
This calculator improves on that by factoring in real light output rather than just spacing rules.
Lighting Layout: Where Should Lights Go?
Getting the number right is only half the job — layout matters just as much.
This tool helps you:
- evenly space lights across the room
- avoid dark spots
- avoid overcrowding the ceiling
Typical spacing guidelines:
- keep lights around 0.5–1m from walls
- space fittings evenly across the room
- avoid placing lights directly above seating or beds unless intentional
The visual layout in the calculator gives you a simple starting point you can adjust to suit your room.
LED Lighting and Energy Savings
If you’re switching to LED lighting, this calculator also shows how efficient your setup will be.
LED lights:
- use significantly less energy than halogen
- last much longer
- reduce running costs over time
You can also explore our approach to longer-lasting, modular lighting in lighting designed for circularity, which focuses on reducing waste and improving lifespan.
Choosing the Right Lights for Your Home
Once you know how many lights you need, the next step is choosing the right type.
For example:
- recessed options like Vero 11 work well for clean, modern ceilings
- higher-output options like Vero 10 can reduce the number of fittings needed
- linear options like Luma 12 are useful for home offices or kitchen runs
The right choice depends on:
- ceiling type
- style
- brightness required
- control (dimming, zoning etc.)
FAQs
How many lights do I need in a room?
It depends on room size, brightness and the type of light. This calculator gives you a tailored estimate in seconds.
How many downlights do I need per room?
Most rooms need around 1 light per 1.5–2 m², but this varies. Use the calculator for a more accurate result.
How many LED lights do I need?
LED lights vary in brightness, so the number depends on lumens rather than just wattage. This tool accounts for that.
How far apart should spotlights be?
Typically 1–1.5 metres apart, depending on ceiling height and beam angle.
Is this calculator accurate?
It’s designed for quick planning and gives a strong estimate. For complex layouts or high-end projects, a full lighting design is recommended.