Free tool
Lighting Calculator
Choose a room and its size to get the recommended light level, total lumens, how many downlights or panels to install and the right colour temperature.
How to use
How to use the lighting calculator
- Pick the room type. The target light level (lux) fills in — raise it for detailed work or older eyes.
- Enter length, width and ceiling height in feet.
- Choose wall and ceiling colour. Dark surfaces absorb light, so you need more fittings.
- Select a fixture or enter the lumens from the box — lumens, not watts, tell you how bright a lamp is.
- Read the count, wattage and a grid layout, then the colour temperature advice for that room.
The maths
How it’s calculated
Area (m²) = L × W (ft) ÷ 10.764
Lumens needed = target lux × area ÷ (UF × MF)
Fixtures = ⌈ lumens needed ÷ lumens per fixture ⌉
UF = utilisation factor (0.6 light / 0.5 medium / 0.4 dark rooms,
reduced for ceilings above 10 ft)
MF = maintenance factor 0.8 (dust and LED ageing)
Target light levels are the typical values Jainify designs to, in line with IS 3646 (Part 1) and NBC Part 8; the tool starts at the middle of each room’s range. This is the lumen method lighting designers use for general (ambient) light. Decorative pendants, cove lighting and table lamps add atmosphere on top of it; task lights such as under-cabinet strips add light exactly where you work.
Worked example
A 12 × 12 ft living room
- Area: 144 sq ft ÷ 10.764 = 13.38 m². Target: 225 lux (living rooms 150–300 lux).
- Light walls (UF 0.6), MF 0.8: 225 × 13.38 ÷ 0.48 = 6,271 lumens.
- 12 W downlights at about 1,080 lm: 6,271 ÷ 1,080 = 5.81 → 6 downlights, 72 W in all — a 2 × 3 grid about 4–6 ft apart.
- Fittings at ₹350–1,200 each: ₹2,100–₹7,200, plus ₹1,200–₹2,500 per new point if wiring is needed.
- Use 2700–3000 K, ideally dimmable, and add a lamp or cove for evenings (reading corner 300 lux).
Recommended light levels and colour temperature
| Room | Light level (lux) | Lumens per sq ft* | Colour temperature | Task light |
|---|---|---|---|---|
| Living room | 150–300 | 29–58 | 2700–3000 K | Reading corner 300 lux |
| Dining | 150–200 | 29–39 | 2700–3000 K | Pendant over the table |
| Kitchen | 300–500 | 58–97 | 3000–4000 K | Worktop task light 500 lux |
| Bedroom | 100–150 | 19–29 | 2700 K | Bedside reading 300 lux |
| Children's room | 200–300 | 39–58 | 3000–4000 K | Study desk 500 lux |
| Study / home office | 300–500 | 58–97 | 4000 K | Desk 500 lux |
| Bathroom | 150–300 | 29–58 | 3000–4000 K | Mirror 300–500 lux |
| Pooja room | 150–200 | 29–39 | 2700 K | Accent on the idol / mandir |
| Corridor / stairs | 100–150 | 19–29 | 3000 K | Step lights at night |
| Office work area | 300–500 | 58–97 | 4000 K | Workstations 500 lux |
| Retail floor | 300–750 | 58–145 | 3000–4000 K | Display accent 2–3× ambient |
*Fitted lumens per sq ft in a light-coloured room (UF 0.6, MF 0.8). Maintained illuminance values in line with IS 3646 (Part 1) — Code of practice for interior illumination and NBC Part 8.
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Open tool →FAQ
Lighting Calculator: common questions
How many downlights do I need for a 10 × 10 ft room?
What is the difference between lux and lumens?
Warm white or cool white — which is better for Indian homes?
What is CRI and does it matter?
Should I rely only on downlights?
Want lighting that changes how a room feels?
We design ceilings and lighting together — cove, accent and task layers, planned before the electrician arrives.
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