Convert candlepower or candela to lumens, convert lumens back to candlepower, or solve for beam angle using the beam’s solid angle, with candela and steradian results.
| Candlepower to Lumens | Lumens to Candlepower |
|---|---|
| 50 cp = 628.32 lm | 100 lm = 7.96 cp |
| 100 cp = 1,256.64 lm | 200 lm = 15.92 cp |
| 200 cp = 2,513.27 lm | 300 lm = 23.87 cp |
| 300 cp = 3,769.91 lm | 500 lm = 39.79 cp |
| 500 cp = 6,283.19 lm | 800 lm = 63.66 cp |
| 750 cp = 9,424.78 lm | 1,000 lm = 79.58 cp |
| 1,000 cp = 12,566.37 lm | 1,200 lm = 95.49 cp |
| 1,500 cp = 18,849.56 lm | 1,500 lm = 119.37 cp |
| 2,000 cp = 25,132.74 lm | 2,000 lm = 159.15 cp |
| 3,000 cp = 37,699.11 lm | 3,000 lm = 238.73 cp |
| 5,000 cp = 62,831.85 lm | 5,000 lm = 397.89 cp |
| 7,500 cp = 94,247.78 lm | 8,000 lm = 636.62 cp |
| 10,000 cp = 125,663.71 lm | 10,000 lm = 795.77 cp |
| 20,000 cp = 251,327.41 lm | 15,000 lm = 1,193.66 cp |
| 50,000 cp = 628,318.53 lm | 20,000 lm = 1,591.55 cp |
| 100,000 cp = 1,256,637.06 lm | 30,000 lm = 2,387.32 cp |
| 200,000 cp = 2,513,274.12 lm | 50,000 lm = 3,978.87 cp |
| 500,000 cp = 6,283,185.31 lm | 100,000 lm = 7,957.75 cp |
| 1,000,000 cp = 12,566,370.61 lm | 200,000 lm = 15,915.49 cp |
| 2,000,000 cp = 25,132,741.23 lm | 1,000,000 lm = 79,577.47 cp |
| Uniform all-direction emission only: lm = cp × 4π and cp = lm ÷ 4π; 4π ≈ 12.57. Modern candlepower is treated as candela. | |
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Candlepower to Lumens Formula
For uniform intensity I within a circular cone of full angle θ, luminous flux is Φ = I × Ω, where Ω = 2π[1 − cos(θ/2)]. Angles in this formula are radians. The special case below assumes uniform emission in all directions.
- Where L is lumens
- CP is candlepower
For uniform emission in all directions (360°), multiply modern candlepower by 4π, approximately 12.57. For a directional beam, use its solid angle instead.
For uniform emission in all directions, divide lumens by 4π. A varying beam profile requires an intensity distribution; peak intensity and nominal beam angle alone do not determine exact total flux.
What is candlepower?
Candlepower is a unit of measure that represents a luminous intensity. Luminous intensity can also be thought of as light intensity.
This calculator uses the modern engineering convention 1 candlepower = 1 candela. Historical candle standards differ and are not converted here.
How to calculate lumens from candlepower?
The following example outlines the steps needed to calculate the total amount of lumens when given candlepower.
First, take a source with 50 candela emitting uniformly in every direction. Under the modern convention used here, this is 50 candlepower.
Its full angle is 360°, and its solid angle is 4π steradians:
I = 50 cd; Ω = 4π sr
Next, multiply intensity by solid angle.
L = I × Ω
L = 50 × 4π
L ≈ 628.32 lumens
