An LED that gives the same light as a 60 W incandescent uses about 9 W and lasts around 25,000 hours – 25 times longer. Even though LEDs cost more to buy, they usually pay for themselves within months.
How to use the LED Savings Calculator
- Current bulb
- Current bulb power
- Current bulb life
- Current bulb price
- LED bulb power
- LED bulb life
- LED bulb price
- Number of bulbs
- Hours per day
- Electricity price
- Years to compare
Results update as you type, and every field accepts the units shown in its menu.
How it works
Choose the type of bulb you have now (or enter its details), enter the LED bulb’s power, life and price, the number of bulbs, hours of use per day, electricity price and the number of years to compare.
Tips
- Use the figures from your own bills and product labels – prices and appliance ratings vary widely.
- Look at yearly totals: small daily costs add up and make it easier to compare options.
- Round quantities up to whole packs, rolls or bulbs when you shop.
- Re-check the numbers when prices change; most results scale directly with the unit price.
Common mistakes to avoid
- Confusing watts (power) with watt-hours or kilowatt-hours (energy).
- Comparing prices without bringing them to the same unit first.
- Ignoring one-off costs such as installation, delivery or replacement parts.
Inputs explained
| Field | What to enter |
|---|---|
| Current bulb | Choose one: Incandescent 60 W, Halogen 43 W, CFL 14 W, Fluorescent tube 32 W … |
| Current bulb power | Units: W, kW, hp |
| Current bulb life | In h |
| Current bulb price | Amount in your currency |
| LED bulb power | Units: W, kW, hp |
| LED bulb life | In h |
| LED bulb price | Amount in your currency |
| Number of bulbs | A number |
| Hours per day | A number |
| Electricity price | Units: /kWh |
| Years to compare | A number |
What each result means
- Hours of use over the period = [Hours per day]×365.25×[Years to compare]
- Current bulbs – total cost = [Number of bulbs]×([Old bulb power]÷1000×[Hours of use over the period]×[Electricity price] + [Old bulb price]×ceil([Hours of use over the period]÷[Old bulb life] – 0.000001))
- LED bulbs – total cost = [Number of bulbs]×([LED bulb power]÷1000×[Hours of use over the period]×[Electricity price] + [LED bulb price]×ceil([Hours of use over the period]÷[LED bulb life] – 0.000001))
- Total savings = [Current bulbs – total cost] – [LED bulbs – total cost]
- Payback time = [Number of bulbs]×[LED bulb price]÷([Number of bulbs]×([Old bulb power] – [LED bulb power])÷1000×[Hours per day]×365.25×[Electricity price]÷12)
Example values
How the main result changes when Current bulb power changes and everything else stays at the example values above:
| Current bulb power (W) | Total savings |
|---|---|
| 30 | 1,292.18 |
| 45 | 1,292.18 |
| 60 | 1,292.18 |
| 75 | 1,292.18 |
| 90 | 1,292.18 |
| 120 | 1,292.18 |
Formula
Electricity cost = watts ÷ 1,000 × hours per day × 365.25 × years × price × bulbsReplacement cost = bulb price × ceil(total hours ÷ bulb life) × bulbsSaving = old total − LED totalWorked example
Inputs — Current bulb: Incandescent 60 W; Current bulb power: 60 W; Current bulb life: 1,000 h; Current bulb price: $1; LED bulb power: 9 W; LED bulb life: 25,000 h; LED bulb price: $3; Number of bulbs: 20; Hours per day: 4; Electricity price: $0.16 /kWh; Years to compare: 5.
Results — Hours of use over the period = 7,305; Current bulbs – total cost = $1,562.56; LED bulbs – total cost = $270.38; Total savings = $1,292.18; Payback time = 3 months.
Frequently asked questions
How much does switching to LED save?
Replacing a 60 W incandescent used 4 hours a day with a 9 W LED saves about $12 a year per bulb at $0.16/kWh.
How long do LED bulbs last?
Typically 15,000–25,000 hours – over 15 years at 3–4 hours a day.
Are LEDs worth it for rarely used lights?
They still save over time, but the payback is slower; prioritise lights used most.
What formula does the LED Savings Calculator use?
Electricity cost = watts ÷ 1,000 × hours per day × 365.25 × years × price × bulbs.