Calculate LED bulb savings
Compare old bulb wattage with LED bulb wattage, then add how often the lights are used. The calculator estimates annual kWh saved, electricity savings and payback period.
Replacing 10 bulbs could save about 558.45 kWh per year.
LED savings formula
LED savings come from the difference between the old bulb wattage and the LED wattage. The bigger the wattage drop and the longer the lights are used, the bigger the saving.
old annual kWh = old watts × bulbs × hours × days ÷ 1,000
LED annual kWh = LED watts × bulbs × hours × days ÷ 1,000
annual saving = kWh saved × electricity unit rate
LED payback period
Payback period is how long it takes for the electricity savings to cover the cost of buying the LED bulbs.
payback years = total LED purchase cost ÷ annual electricity saving
If the purchase cost is low and the lights are used often, the payback can be quick. If the lights are rarely used, the payback will take longer.
Why LED bulbs can reduce lighting costs
LEDs normally produce similar brightness with much lower electricity use than older incandescent or halogen bulbs. Energy Saving Trust says LEDs are the most energy efficient light bulb and can use about 80% less electricity than halogen lights for similar power output.
Find old wattage
Check the old bulb label, packaging or fixture information.
Choose LED wattage
Compare brightness using lumens, not just watts.
Estimate payback
Compare annual electricity saving against the LED purchase cost.
Watts vs lumens
Watts measure power use. Lumens measure brightness. When switching to LEDs, choose bulbs based on lumen output so the room is still bright enough.
A lower-wattage LED may give similar brightness to a much higher-wattage older bulb, which is why the running cost can be lower.
How LED savings fit into your energy bill
Lighting is only one part of a household energy bill, but it is often one of the easier areas to improve. For a fuller picture, compare lighting savings with appliance costs and your whole bill estimate.
Compare appliance costs
Use the electricity cost calculator to estimate the running cost of any appliance.
Estimate your full bill
Use annual gas and electricity usage, unit rates and standing charges to estimate your whole energy bill.
LED savings calculator FAQs
How do I calculate LED savings?
Compare old bulb wattage with LED wattage, multiply the difference by bulbs and usage hours, then apply your electricity unit rate.
Are LED bulbs always cheaper to run?
Usually yes, when they provide similar brightness with lower wattage. The exact saving depends on wattage, hours used and electricity price.
What is LED payback?
It is the time it takes for electricity savings to cover the cost of buying the LED bulbs.
Should I compare watts or lumens?
Use watts for running cost and lumens for brightness. A good LED replacement should save power while still giving enough light.