Lighting Calculator (2024)

In the first step of your calculations, you need to choose the type of area and activity that you want to illuminate.

Simply select one of the options from the list, and our lighting calculator will automatically determine the optimal level of illumination in lux or foot-candles (that is, how much light should be incident on the surface). Intuitively, ambient light in the bedroom shouldn't affect our preparations for sleep time and won't be as intensive as the light required for sewing.

The next thing you need to determine is the illuminated area. In the case of a bedroom or a bathroom, it will simply be the room's total area. If you're trying to figure out LED lighting for your kitchen counter, the illuminated area will be calculated as the length of the counter multiplied by its width.

Once you know all these values, the foot-candle calculator will determine how many lumens you need. We use the following equation:

You can use illumination units of lux or foot candles. If you want to recalculate between these units, remember that one foot-candle equals $10.764\ \text{lux}$10.764lux.

Also, check out our lumens to watts calculator if you're curious about how many lumens various light bulbs produce under a given wattage.

1. Choose the area of the house that you want to illuminate. Let's say you're planning the lighting for your kitchen, including the kitchen counter.

   See Also

   How to Calculate Lighting: An Authoritative Guide

2. Check the optimal lighting level. For the whole kitchen, it is 108 lux, and for the counter (detailed tasks) – $538\ \text{lux}$538lux.

3. Determine the dimensions of your illuminated space. The whole kitchen is a rectangle of length 4 m and width 2.5 m, so that you can calculate the area as:

   $A_1 = 4 \cdot 2.5 = 10\ \text{m}^2$A1​=4⋅2.5=10m2

   The counter is 4 meters long and 60 cm wide:

   $A_2 = 4 \cdot 0.6 = 2.4\ \text{m}^2$A2​=4⋅0.6=2.4m2

4. Multiply the required illumination level by the area to figure out how many lumens you need:

   $L_1 = 108 \cdot 10 = 1080\ \text{lumens}$L1​=108⋅10=1080lumens

   $L_2 = 538 \cdot 2.4 = 1291\ \text{lumens}$L2​=538⋅2.4=1291lumens

5. Then, choose the type of light bulb you want to use. Let's assume you're using a standard bulb that emits 800 lumens for the kitchen and small LED lights that emit 200 lumens each above the counter.

6. Divide the total number of lumens by the efficiency of the bulb and round up to figure out the number of bulbs you need:

   $n_1 = \frac{1080 }{800} \rightarrow 2\ \text{bulbs}$n1​=8001080​→2bulbs

   $n_2 = \frac{1291}{200} \rightarrow 7\ \text{bulbs}$n2​=2001291​→7bulbs

   You will need two light bulbs (800 lumens each) to illuminate the whole kitchen and additional 7 LED lights (200 lumens each) above the counter.

If you're wondering how much you'll pay for electricity when using all of this lighting, take a look at the electricity cost calculator!

To calculate the lighting of an area:

1. Measure the dimensions of the surface of interest.
2. Compute the area of the surface.
3. Calculate the lumens required using the formula
   lumens = lux × area

The lux is a measurement of the received light per area unit. The lumens is a unit that measures the amount of light emitted by a light source.

About 6,500 lumens. To calculate this result:

1. Compute the area of the room:
   area = 4 m × 5 m = 20 m²
2. Choose the right amount of lux you need. For a studio, the recommended value is 323 lx.
3. Find the result using the formula:
   lumens = lux × area = 323 lx × 20 m² = 6,460 lm

If you plan to use lightbulbs with an intensity of 1600 lm, you'll need five of them.

A bedroom must have different lighting for different uses:

• For bedtime use, you will need a lower amount of lumens. A good approximation is 54 lx.
• For reading or other activities, the lighting must be higher. You can use up to 430 lx.
• For specific tasks (sewing, other hobbies), the lighting must rise to almost 540 lx.

This amount of light can be spread over multiple lightbulbs.

The lumen is a unit of luminous flux; lumens correspond to the amount of light emitted by a source, such as a lightbulb or a candle, regardless of direction.

Lux is used to measure the amount of light shining on a surface. A high amount of lux corresponds to a brightly lit surface.

Lux and lumens are related by the formula lumens = lux × area.