Calc4Living

Home Energy · Free calculator

LED Savings Calculator

Compare the electricity use and running costs of existing bulbs with LED replacements. See energy savings and cost differences for the same usage.

Your inputs

All fields are required. Prefilled values are an editable example, not local price or usage recommendations.

No exchange rates or conversion. Enter electricity prices in the selected currency per kWh, not in cents or pence. Changing currency clears the result.

Actual electrical wattage, not an equivalent brightness rating.

Actual LED wattage for comparable light output.

Whole number, zero or more.

Average daily hours drawing the entered power, from 0 to 24.

Enter major currency units per kWh: for example, 0.20 means 20 cents or pence, not 20.

Whole days, 0–366. The period result uses this value; monthly and annual comparisons use 30 and 365 days.

Your estimate

Energy & savings

Review the example inputs, enter your local electricity price, then calculate. Results clear when inputs change so an old estimate is never shown for new values.

How much electricity can replacing bulbs with LEDs save?

Energy saved (kWh) = (old watts − LED watts) ÷ 1,000 × bulb count × hours/day × days. Cost savings = energy saved × electricity price per kWh.

Worked example

Replacing 10 bulbs rated 60 W with 9 W LEDs, used 4 hours daily at 0.20/kWh, saves 2.04 kWh and 0.408 per day. Over 30 days: old cost 14.40, LED cost 2.16, saving 12.24. Annual saving is 148.92.

Example amounts use whichever currency you select; they are arithmetic illustrations, not quoted local rates.

Assumptions & limitations

  • Compare bulbs with similar light output (lumens), not just different wattages. Assumes all bulbs run for the same daily hours at their stated power.
  • Negative savings mean the replacement uses more energy and costs more. Purchase prices, bulb lifetimes, dimmers, maintenance and any heating/cooling effects are excluded.

Further reading