Channel Letter Calculator

Front-lit faces need about 3 modules per foot of letter height because light only has to fill the acrylic face. Halo-lit letters push light backward against the wall around the return, which needs more modules to look even, so the calculator uses 4 per foot; combo lighting runs both effects at once and uses 6. Fabrication cost scales the same way, with 1.3x and 1.5x multipliers for halo and combo respectively to account for the extra LEDs and wiring.

Real channel-letter signs need gaps between letters for legibility and mounting hardware, so this calculator assumes each letter's width is about 60% of its height, then adds roughly 15% of that width as spacing between every pair of adjacent letters before summing everything into a total footprint in feet. For an 8-letter sign that's 7 spacing gaps added to the 8 letter widths.

Return depth is the side wall of each letter that gives it dimension, and it feeds into fabrication cost as a factor scaled against the standard 5-inch depth: shallower letters cost a bit less, deeper letters a bit more. It doesn't affect LED count or power draw in this calculator, since module count is driven by height and illumination type rather than depth.

Power draw here is a straight multiplication of LED module count by 0.72 watts, the typical draw of a 3-LED SMD module, so it's a reasonable ballpark but doesn't account for the specific modules and transformers your sign shop actually specs, or line loss over long wire runs. Since it also doesn't check your electrical panel's spare capacity, an electrician needs to confirm whether an existing circuit can carry the load or whether you need a dedicated circuit or additional transformer.