ganak.appCan Light Calculator
Plan can light spacing, placement, rows, columns, wall offset, fixture count, and estimated installation cost for any room.
Target: 15 fc (161 lux), General ambient lighting, cozy atmosphere
Typical LED 6-inch downlight: 700-1,000 lm
Spacing = 0.8 × ceiling height, General downlighting, most common
Fixtures Needed
4
2 rows × 2 columns · Living Room / Bedroom · 15 fc target
Layout & Spacing
How your fixtures are arranged across the ceiling
Costs & Energy
Estimated installation cost and annual energy usage
Layout Preview
Each dot represents one can light fixture
What Is a Can Light Calculator?
Plan your lighting layout before you buy or install
A can light calculator helps homeowners, contractors, and designers determine exactly how many can lights a room needs, and where to place them. Can lights, also called recessed lights or pot lights, are ceiling-mounted fixtures that sit flush with the ceiling. Instead of guessing, you enter your room dimensions, ceiling height, and fixture specs to get a precise fixture count, spacing grid, layout plan, and installation cost estimate.
Whether you're planning lighting for a kitchen, living room, basement, or office, the can light calculator gives you exact rows × columns placement, wall offset, and estimated installed cost per fixture, so you can buy the right number of lights before you start cutting holes in your ceiling.
How Is Can Lighting Calculated?
Step-by-step formulas with a worked example
Core Formulas
1.Enter Room Dimensions
Measure your room length and width. Select your unit system (imperial ft/in or metric m/cm) and enter the ceiling height, this is critical for spacing calculations. The calculator uses ceiling height to determine fixture spacing via the 0.8× rule.
2.Choose Room Type & Fixture Specs
Pick your room type from the dropdown. The calculator applies standard foot-candle planning targets: 15 fc for living rooms, 40 fc for kitchens, 80 fc for task areas. Then enter your fixture lumens (typically 700 to 1,000 for a standard 6-inch LED downlight).
3.Review the Layout
The calculator shows fixtures needed, spacing, rows × columns grid, and wall offset. Check the visual dot-grid preview to see how fixtures are arranged. Adjust spacing rules or room dimensions to compare different layouts.
4.Check Costs & Energy
Expand Advanced Options to enter watts per fixture and your electricity rate. Get annual energy cost and estimated total installed cost including labor. Add a waste factor for spares.
Worked Example: 12 × 12 ft Living Room, 8 ft Ceiling
Area
144
sq ft
Target
15
fc
Lumens
2,160
lm
Grid
2×2
4 lights
Result
4
fixtures
Room Type Brightness Guide
Common foot-candle planning targets by space
Different rooms need different brightness levels. The calculator uses common foot-candle planning targets to determine how many lumens your room needs.
| Room Type | Foot-Candles | Lux |
|---|---|---|
| Living Room / Bedroom | 15 | 160 |
| Kitchen (Ambient) | 40 | 430 |
| Kitchen (Task / Island) | 80 | 860 |
| Bathroom | 35 | 375 |
| Hallway / Corridor | 8 | 85 |
| Office / Study | 40 | 430 |
1 foot-candle (fc) = 1 lumen per square foot. 1 fc ≈ 10.76 lux. Values are common foot-candle planning targets used by lighting professionals for residential and commercial spaces.
Key Considerations
What to keep in mind when planning can lighting
Ceiling Height Drives Spacing
Higher ceilings need wider fixture spacing because light spreads more before reaching the floor. The calculator uses 0.8× ceiling height by default. For vaulted or sloped ceilings, average the highest and lowest points.
Beam Angle Affects Coverage
Narrow beam angles (30°) concentrate light in a smaller area, use closer spacing. Wide flood beams (90°+) spread light broadly and can use wider spacing. The calculator adjusts for this in Advanced Options.
Task vs Ambient Lighting
Kitchens and offices need higher brightness (40 to 80 fc) for work surfaces. Living rooms and bedrooms can use lower levels (15 fc) for ambient comfort. Select the right room type for accurate results.
Wall Offset Is Flexible
Place the first row of lights at half the fixture spacing from the wall. Smaller offsets light walls and artwork better; larger offsets reduce wall washing. Adjust the offset slider to match your preference.
Plan for Dimmers and Zones
The calculator gives total fixture count for general lighting. In practice, split lights across multiple dimmer switches or circuits, especially in kitchens and large open-plan spaces.
Common Can Light Placement Mistakes
Avoid these pitfalls when planning your layout
Ignoring ceiling height
A common mistake when placing can lights is using the same spacing regardless of ceiling height. An 8-foot ceiling typically needs 6 to 7 ft between can lights; a 12-foot ceiling needs 9 to 10 ft. Failing to adjust for ceiling height leads to dark spots or overly bright areas.
Choosing the wrong can light size
Four-inch can lights work well for accent and task lighting in 8 to 10 ft ceilings, while 6-inch cans are the most common all-purpose choice. Using a size that's too small can leave the room feeling dim; too large and it can overpower the space.
Skipping dimmers and zones
Installing all can lights on a single switch forces all-or-nothing lighting. Split fixtures across 2 to 3 dimmer switches to create flexible lighting scenes, brighter for cleaning and cooking, dimmer for relaxing and entertaining.
Placing can lights too close to walls
Can lights placed too close to walls create harsh shadows and uneven lighting. The standard rule is to place the first row at half the fixture spacing from the wall. The calculator's wall offset feature helps you get this right.
Frequently Asked Questions
Common questions about can light placement, spacing, and calculations
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Last updated Jun 25, 2026