Convert volts to lumens from voltage, current and lamp type, using typical lumens per watt for LED, CFL or halogen bulbs, or solve for the amps or volts needed.

Default 120 V, standard US household mains. Change it for 230 V mains or low-voltage lighting.

Typical lumens per watt for each lamp type; check the package for your bulb’s lumens and watts.

Optional settings

Volts To Lumens Formula

The following formula can be used to estimate lumens from voltage when the electrical current and the light sourceโ€™s luminous efficacy are known.

L = V ร— I ร— eta

Variables:

  • L is the light output (lumens)
  • V is the voltage (volts)
  • I is the electrical current (amps)
  • ฮท is the luminous efficacy (lumens per watt, lm/W)

This relationship comes from two standard definitions: DC or unity-power-factor electrical power is P = V ร— I (watts); for single-phase AC use P = Vrms ร— Irms ร— PF, and light output can be estimated as L = P ร— ฮท (lumens), where ฮท is luminous efficacy in lm/W. In real lighting systems, current and efficacy depend on the driver, LED/lamp type, temperature, optics, and operating pointโ€”so voltage alone cannot be converted to lumens without additional information.

Volts to Lumens Example Table (DC/unity PF; Current = 1 A, Efficacy = 100 lm/W)
Volts (V) Lumens (lm)
0.550
1100
1.5150
3300
3.3330
5500
6600
9900
121200
181800
242400
363600
484800
606000
727200
969600
11011000
12012000
22022000
24024000
Example only. Uses L = V ร— I ร— ฮท with I = 1 A and ฮท = 100 lm/W. Do not assume a fixed current from supply voltage; actual current and lumen output depend on the lamp/driver and operating conditions.

What is Volts To Lumens?

โ€œVolts to lumensโ€ usually refers to estimating a lightโ€™s output (lumens) from electrical information. There is no universal direct conversion from volts to lumens because volts measure electrical potential (voltage), not power. To estimate lumens you generally need power (watts) and luminous efficacy (lm/W), or voltage plus current and, for AC, power factor (single-phase real power is P = Vrms ร— Irms ร— PF).

How to Calculate Volts To Lumens?

Select estimated light output, current for target lumens, voltage for target lumens, or required luminous efficacy. Enter the known values with units, and pick a lamp type or enter a custom lm/W. Choose DC/unity power factor or single-phase AC; for AC use RMS voltage/current and true power factor. Select Calculate; input edits mark the previous result as outdated. Values are saved in this browser; Reset clears this calculatorโ€™s saved data. Use complete luminaire efficacy (lumens per real input watt) at the same operating point, as defined by DOE lighting guidance. Driver and optical losses are already reflected in complete-luminaire lm/W and should not be deducted again.

  1. Determine the voltage (V) across the light/load in volts.
  2. Determine the electrical current (I) through the light/load in amps.
  3. Determine the luminous efficacy (ฮท) in lumens per watt (lm/W) for the light source at its operating conditions.
  4. Calculate light output: L = V ร— I ร— ฮท (lumens).
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

voltage (V) = 12 volts

current (I) = 0.50 amps

luminous efficacy (ฮท) = 100 lumens per watt