TOOLS
Lighting Electricity Cost Calculator
Estimate running costs. Compare setups. See what a change could save.
Your running cost
USDComplete the highlighted fields to calculate your running cost.
Electricity costs only. Excludes fixed charges, demand charges and maintenance. Flat-rate estimate; no automatic tariff lookup.
Good to know
Which power figure should I enter?
For LED strips, use watts per metre or foot from the strip’s specification. For fixtures, use the total input watts per fixture, including its driver. For a measured setup, use the wattmeter reading for the entire group at the mains input.
A power supply’s 150 W rating describes its output capacity. It does not mean your lights continuously consume 150 W. “60 W equivalent” describes light output, not actual LED power consumption.
Does 50% brightness mean half the cost?
Not necessarily. The relationship depends on the driver, dimming method and LED channels in use. Colour and colour temperature can also affect the power of RGB and tunable-white strips.
For an estimate at your usual brightness, choose Measured and enter the wall-side watts at that setting. Rated strip power gives a nominal full-power estimate.
What does driver efficiency change?
The driver draws more power from the mains than it supplies to the strip. A 72 W strip with a 90% efficient driver draws an estimated 80 W: 72 ÷ 0.90.
The 90% starting value is an example. Actual efficiency varies with the driver and load. Fixture input ratings and wall-side measurements already include driver losses, so the calculator does not add them again.
Which electricity price should I use?
Use your bill’s per-kWh electricity charge, including other charges proportional to kWh if applicable. Enter 0.20 for 20 cents. Do not divide the whole bill by kWh if it includes fixed or demand charges.
This tool uses one flat rate. For a time-of-use tariff, use a usage-weighted average for the hours your lighting runs. The currency selector changes the label, not the exchange rate.
How are monthly costs and standby calculated?
Operating hours are hours per day × days per year. Monthly average is the annual total divided by 12; daily average is divided by 365. These are annualised averages, not a forecast for a particular bill.
Standby power applies to 8,760 minus the operating hours. This assumes the group stays connected all year. Use 0 W if a mains switch disconnects the entire group whenever it is off.
What does the payback figure include?
Simple payback is the extra upfront cost divided by annual electricity savings. For an upgrade, include the replacement equipment and installation, less rebates. For two new proposals, enter the difference between their installed costs.
It excludes financing, tariff changes, maintenance and replacement. If the alternative does not lower electricity costs, there is no simple payback from electricity savings.
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For AI agents: instructions and calculation APIs
Read the calculation instructions in Markdown and the proposed request/response schemas in OpenAPI. The local example below uses the same model as this web calculator and its offline copy.
API draft — not deployed. This preview does not provide a hosted calculation endpoint. The proposed route below must not be called as a live service.
- Lighting Electricity Cost Calculator — Full instructions (Markdown, draft)
- OpenAPI draft — request and response schemas
- Agent site index — existing live tools
Lighting Electricity Cost Calculator
POST /api/tools/v1/lighting-cost
Content-Type: application/jsonEstimate electricity use and running costs for LED strips, fixtures or measured lighting loads. Groups have independent operating schedules. Optional comparison calculates annual savings and simple payback. Currency is a label; no exchange-rate conversion is performed.
Use metres, watts, hours per day and days per year. Fixture input power and measured wall-side power already include driver losses. Strip efficiency is explicit; null excludes those losses. Standby applies to all non-operating hours in a 365-day year. Fixed charges, demand charges, maintenance and changing tariffs are excluded.
Example request
{
"currency": "USD",
"electricityRatePerKwh": 0.2,
"baseline": {
"groups": [
{
"name": "LED strip",
"power": {
"kind": "strip",
"lengthM": 5,
"powerPerMeterW": 14.4,
"driverEfficiencyPercent": 90
},
"hoursPerDay": 8,
"daysPerYear": 365,
"standbyInputPowerW": 0
}
]
}
}Local example response
Open links.share from a successful response to restore the calculation in this preview. The web calculator can copy results, export CSV, print or save PDF, and download a working offline HTML copy. The offline file is not a calculation API.
Validation and error handling
The draft requires JSON numbers, strict property names and the power fields for the selected kind only. No value is inferred from an unrelated power-supply rating. Validation must succeed before results are used.
Hosted request limits, timeouts, authentication, CORS and rate limits are not established for this draft. Do not assume that the limits of other LEDYI tools apply. For a future HTTP integration, check both HTTP status and Content-Type before parsing JSON; edge errors can be HTML or appear as browser network failures. Never present an error or an older calculation as a new success.