Lighting Calculator
Determine the recommended lumens (light output) needed for proper room lighting. Different room types require different lighting levels for optimal comfort and functionality.
Lighting Recommendations
How the Lighting Calculator Works
Light is measured in lumens (how much a source emits) and lux (how much lands on a surface — one lux is one lumen per square meter). Every room type has a recommended lux level from illumination engineering practice, and the calculator multiplies that by your floor area.
Total lumens = room area (m²) × recommended lux for the room type
A relaxed living room wants around 200 lux, a kitchen where you handle knives around 400, a home office 500, and a workshop 750 or more. The calculator returns the total lumens the room needs, plus the equivalent wattage in LED (about 90 lumens per watt) and incandescent terms — useful for translating to what's printed on bulb boxes. As a rule of thumb, a standard LED bulb produces about 800 lumens, so the result also tells you roughly how many bulbs you're distributing around the room.
How to Plan Room Lighting in Layers
The total lumens figure is a budget, not a shopping list for one giant ceiling light. Good rooms split it across three layers: ambient light (the general fill — ceiling fixtures, large pendants), task light (reading lamps, under-cabinet strips, desk lamps aimed where work happens), and accent light (picture lights, shelf strips — the layer that makes a room feel designed). A common split is roughly 60% ambient, 25% task, 15% accent.
Distribute rather than concentrate: four 800-lumen sources beat one 3,200-lumen source in every way that matters — fewer shadows, dimmable zones, and light where you actually sit. Dark walls absorb light, so a room painted in deep colors can need 25–50% more lumens than the same room in white; factor that in after using our paint calculator for a dark scheme.
Also match color temperature to the room: 2700–3000 K (warm white) for living spaces and bedrooms, 3500–4000 K (neutral) for kitchens and bathrooms, 4000 K+ for workshops. If a ceiling fan is part of the plan, fan-light combos count toward ambient light — size the fan first with the ceiling fan calculator, and check cooling needs with the BTU calculator.
Recommended Light Levels by Room
| Room | Target lux | Example: 15 m² room |
|---|---|---|
| Hallway | 100–150 | 1,500–2,250 lm (2–3 bulbs) |
| Bedroom | 150–200 | 2,250–3,000 lm (3–4 bulbs) |
| Living room | 200–300 | 3,000–4,500 lm (4–6 bulbs) |
| Kitchen | 400–500 | 6,000–7,500 lm (8–9 bulbs) |
| Home office | 500–750 | 7,500–11,250 lm (9–14 bulbs) |
Common Mistakes to Avoid
- Relying on one central ceiling light — the classic recipe for a flat, shadowy room.
- Buying bulbs by watts instead of lumens; watts measure consumption, not brightness.
- Using cool white (4000 K+) in living rooms and bedrooms, where it reads clinical.
- Ignoring wall color — deep-toned rooms need substantially more light than white ones.
Frequently Asked Questions
How many lumens do I need for a living room?
Plan around 200–300 lux, which for a typical 20 m² living room means 4,000–6,000 total lumens — five to seven standard 800-lumen LED bulbs spread across ceiling fixtures, floor lamps, and table lamps. Dimmers effectively give you several rooms in one.
What is the difference between lumens and watts?
Lumens measure light output; watts measure energy consumption. They correlated in the incandescent era (60 W ≈ 700 lm), which is why we still think in watts. A modern LED delivers the same 700–800 lumens from 8–10 W, so always shop by the lumen figure on the box.
What color temperature should my bulbs be?
Warm white (2700–3000 K) for living rooms and bedrooms — it flatters skin and feels relaxing. Neutral (3500–4000 K) for kitchens and bathrooms where you want clarity. Cool daylight (5000 K+) belongs in workshops and garages. Mixing temperatures in one room usually looks accidental.
How many light sources should a room have?
At least three in any room you spend time in, spread between ambient, task, and accent layers. Divide the calculator's total lumens by 800 (a standard LED bulb) for a bulb count, then group them: a 4,800-lumen living room might be one ceiling fixture, two lamps, and an LED shelf strip.