basic

Christmas Light String Wattage Calculator

W = strings × bulbs × W_per_bulb.

Compute the total watts and amps drawn by a Christmas / holiday lighting display: total_W = strings × bulbs_per_string × watts_per_bulb. Verifies that you stay within the typical 80 % rating of a 15 A circuit (≈ 1440 W on a 120 V line).

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Marcus Laurent By Marcus Laurent
Published Last reviewed 1 min read

Inputs

W
V

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

Total W = strings × bulbs × W_per_bulb; A = W / V.

In depth

Compute the total watts and amps drawn by a Christmas / holiday lighting display: total_W = strings × bulbs_per_string × watts_per_bulb. Verifies that you stay within the typical 80 % rating of a 15 A circuit (≈ 1440 W on a 120 V line).