TOOLS
İç Mekan Aydınlatma Hesaplayıcısı
Find how much light you need. Adjust the inputs. See the difference.
01 Your room
Enter the space to illuminate
Uzunluk
Width
20 m²
02 Lighting goal
What will you do here?
Target light level (lx / fc)
Choose a purpose for a reference, or enter your own target.
03 Your lights
Lumens per fixture
Use the complete fixture’s lumens from its specification, after any lens or diffuser.
Calculation assumptions
Utilization (slider)
0.60
Bakım (slider)
0.80
Drag a slider or type an exact value. Results update immediately.
Understanding the estimate
Light on a surface is measured as illuminance in lux: the number of lumens that actually reach each square metre. A fixture’s total output (lumens) is not what lands on the work plane – part is lost to the room and part decays over time. That is why the calculator divides by utilization and maintenance factors.
Required total output (lm) = target illuminance (lx) × area (m²) ÷ (utilization × maintenance)
Lumen (lm)
Total light emitted by the fixture – the specification value after the lens or diffuser.
Lux (lx) = lm / m²
How bright a surface actually looks. 1 lux = 1 lumen spread over 1 square metre.
Utilization factor
How efficiently the room delivers the light to the work plane – ceiling, wall reflectance and fixture optics. 0.60 is a typical assumption.
Maintenance factor
Output decays as lamps age and dust builds up. 0.80 means 20% is lost over the maintenance cycle.
Fixtures needed = ⌈ required total output ÷ lumens per fixture ⌉ · Maintained average (lx) = installed lm × util × maint ÷ area
Your estimate · Updates as you type
ESTIMATED QUANTITY
13
fixtures · 1,000 lm each
Maintained average 312 lx · 4% above target
Fixtures
13
Oda
5 m × 4 m
Required total output
12,500 lm
Installed total output
13,000 lm
Symbols show quantity, not installation positions. No photometric layout is calculated. Utilization 0.60 · Maintenance 0.80 · Assumed.
Good to know
Why can the suggested quantity seem high?
Because you are paying for the light that actually reaches the work plane, not the raw fixture output. Utilization (room losses) and maintenance (aging and dust) mean you install more lumens than the simple target × area number. That headroom is why the maintained average stays at target over the service life.
What if I have not selected a light?
Enter an assumed lumens-per-fixture value based on the type you plan to use – for example around 800–1,600 lm for a typical indoor LED fixture. The result tells you how many you need; swap in the real fixture’s lumens once selected to re-run the count.
Can I use LED strips or linear lights?
Yes – treat a linear run as a series of fixture equivalents. Divide the required total output by the lumens per metre of your strip to get the total length needed, then compare it against the required fixture count for a sense of scale.
Do the symbols show where to install the lights?
No. The estimate gives a quantity and a maintained average illuminance, not a photometric layout. Spacing, uniformity, glare and exact placement need a photometric design for your room geometry.
Method and assumptions
This is a lumen-method planning estimate: required output = target lx × area ÷ (utilization × maintenance). It assumes a typical room and evenly distributed light; it excludes natural light and does not model glare or uniformity.
Keep your calculation and share your room dimensions, mounting details and application with our team.
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