Room Lighting (Lux) Calculator
Room size and target lux → total lumens and number of fittings, with sourced reference lux values.
Open the toolLED lighting · Light fittings · Car lighting
Lighting calculators you can check
EyourLife is about LED lighting, light fittings and car lighting. The calculators below work out lux, lumens, LED strip power, beam spread and battery runtime from the numbers you enter, and every page shows its formula, units, sources and limits.
Free calculators that run in your browser
All calculatorsWatts to Lumens Converter
Watts ↔ lumens for LED, halogen and incandescent bulbs, with the efficacy values and sources shown.
Open the toolLED Strip Power Supply Calculator
W per metre × length → total watts, amps and a power-supply rating with headroom.
Open the toolBeam Angle and Spot Size Calculator
Mounting height and beam angle → spot diameter, or the beam angle for a wanted spot size.
Open the toolBattery Runtime Calculator for LED Lights
Battery capacity and power draw → estimated runtime, with usable capacity and converter losses.
Open the toolWhich calculator do I need?
Planning a room
The lux calculator turns room size and a target illuminance into the total lumens needed.
Replacing a bulb
The watts to lumens converter compares LED, halogen and incandescent bulbs by light output.
Installing LED strip
The power supply calculator adds up watts and amps and adds headroom.
Spotlights and batteries
Check spot size from beam angle and battery runtime for portable and 12 V lights.
Frequently asked questions
What is the difference between lumens and lux?
Lumens (lm) measure the total light a lamp gives out. Lux (lx) measure how much of that light lands on a surface: one lux is one lumen per square metre. The room lux calculator links the two for a room.
Can these calculators measure my lights?
No. They only calculate from the numbers you enter, such as the values on a bulb’s packaging or a datasheet. Measuring real light needs a calibrated meter.
Does EyourLife say which car bulbs or lights may be used on the road?
No. Rules for vehicle lighting depend on the country and the vehicle. Check your vehicle manual and the official vehicle lighting rules where you drive.
Can I wire lights to mains electricity using these pages?
The calculators only cover figures such as power, current and runtime. Mains electrical work should be done by a qualified electrician following the wiring rules where you live.
How does EyourLife make money?
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