Here's the
website where I dug up that equation I've used:
(1-abs(cos[beam angle]))*2*pi*[cd]
On a spreadsheet:
=((1-ABS(((COS([beam angle]/2*(PI()/180))))))*2*PI())*([mcd]/1000)
Here are some of the results I generated (likely complete with a current consumption fat-finger on that "1.3W" Nichia):
<font class="small">Code:</font><hr /><pre>
Manuf. Model Format Vf mA mW color mcd angle area mcd*area Lumens
Lumex SSL-LX5093XUWC T1-3/4 3.60 30.00 108.00 white 2300 15 0.0545 125.2379 0.1236
Lumex SSL-LX5093XUWC T1-3/4 3.60 30.00 108.00 white 2300 15 0.0545 125.2379 0.1236
Lumex SSL-LX3054UWC/A T1 3.60 30.00 108.00 white 1100 20 0.0977 107.4435 0.1050
Nichia NBCW011 SMD 3.60 80.00 288.00 white 2200 120 9.4248 20734.5115 6.9115
Nichia NACW019 SMD 3.60 40.00 144.00 white 1100 120 9.4248 10367.2558 3.4558
Nichia NCCW022 SMD 3.80 350.00 1330.00 white 1850 80 2.2120 4092.1228 2.7195
Nichia NSCW017 SMD 3.60 20.00 72.00 white 600 120 9.4248 5654.8668 1.8850
</pre><hr />
The "area" and "mcd*area" fields were attempts to formulate a metric before I found the mcd-lumens equation I'm using.
I don't even begin to assume that this calculation is anywhere near dead-nuts - I used it to get a rough comparison between LEDs and other light sources for work once, and have used it to get a feel for general LED brightnesses.