★ EVERYDAY · ENERGY · COMPARISONS
LEDs save $103.70 a year at the defaults: $122.64 for incandescents against $18.94 for LEDs. Enter your bulb count, hours per day, watts, bulb prices, and electricity price to price both options for your home. This is energy plus replacement bulbs only: the fitting, dimmer, and your time changing bulbs are not included.
An incandescent bulb is cheap to buy and expensive to run: it burns 60 watts and lasts about 1,000 hours, so at 3 hours a day you replace it roughly once a year. An LED burns 9 watts and lasts about 25,000 hours, so the same socket needs a new bulb roughly once every 23 years. This calculator prices both sides — electricity and replacements — at your numbers.
At 3 hours a day each bulb burns 1,095 hours a year. An incandescent bulb at 60 watts uses 65.7 kWh in that time, and ten of them use 657 kWh, which costs $111.69 at $0.17 per kWh. An LED at 9 watts uses 9.855 kWh per bulb, and ten use 98.55 kWh, costing $16.75. That electricity gap alone is $94.94, and replacements add the rest: the incandescent life of 1,000 hours means 10.95 bulbs a year across ten sockets at $1 each, or $10.95, while the LED life of 25,000 hours means 0.438 bulbs a year at $5 each, or $2.19. Add them up and the totals are $122.64 against $18.94, a saving of $103.70 a year, or $12.26 against $1.89 per bulb per year. The extra $4 per LED bulb pays for itself in about five months at these settings, because each socket saves about $10.37 a year.
Bulb count scales everything proportionally: 5 bulbs gives $61.32 against $9.47, a saving of $51.85, while 20 bulbs gives $245.28 against $37.89, a saving of $207.39. Hours matter just as much: at 1 hour a day the saving shrinks to $34.57, and at 5 hours a day it grows to $172.83. A higher power price widens the gap without changing the winner: at $0.30 per kWh the totals are $208.05 and $31.76, a saving of $176.29. Nothing in these branches flips the winner, and that is the honest headline: at any realistic hours, count, or power price, LEDs win on yearly cost, because they use roughly one-seventh of the energy and last roughly twenty-five times longer. What can change is how much the win is worth to you: a rarely used closet bulb saves pennies a year, while a kitchen full of bulbs burning all evening saves hundreds. Rounding convention: each yearly total is rounded to cents first, and the saving is the difference of those rounded totals, so the figures always add up exactly as printed. Displayed energy and bulb lines are each rounded to cents from unrounded values, so in rare cases (for example 5 bulbs) those two lines can differ from the rounded total by a cent.
| Output | Formula | What it means |
|---|---|---|
| Annual hours | Hours per day × 365 | 3 × 365 = 1,095 hours at the defaults. |
| Energy (kWh) | Watts × annual hours ÷ 1000 × bulbs | 657 kWh incandescent, 98.55 kWh LED at the defaults. |
| Bulbs per year | Bulbs × annual hours ÷ bulb life | 10.95 incandescent (1,000 h life), 0.438 LED (25,000 h life) at the defaults. |
| Energy cost | Energy kWh × electricity price | $111.69 incandescent, $16.75 LED at the defaults. |
| Bulb cost | Bulbs per year × bulb price | $10.95 incandescent, $2.19 LED at the defaults. |
| Yearly total | Energy cost + bulb cost, rounded to cents | $122.64 incandescent, $18.94 LED at the defaults. |
| LED saving | Rounded incandescent total − rounded LED total | $122.64 − $18.94 = $103.70 a year at the defaults. |
This is a yearly-cost model, not a meter reading. It uses fixed rated lives of 1,000 hours for incandescents and 25,000 hours for LEDs, while real life varies with switching frequency, heat, vibration, and dimming: frequently switched LEDs in enclosed fixtures may fall short of 25,000 hours, and cheap incandescents may beat or miss 1,000 hours. It assumes every bulb burns the same hours at its rated watts, while dimmed bulbs draw less power and produce less light, and it counts fractional bulbs per year (0.438 LEDs) because that is the correct way to spread a long-lived bulb's cost across years, not a claim that you buy part of a bulb. Electricity prices, taxes, and standing charges vary by tariff, so enter your own per-kWh price for the most accurate result.
Bright Side Kit. "LED vs Incandescent Bulbs: Yearly Energy Cost Calculator" https://brightoolbox.com/led-vs-incandescent/ Accessed October 24, 2026.At the defaults, $103.70 a year across 10 bulbs: $122.64 for incandescents against $18.94 for LEDs. Per bulb that is $12.26 against $1.89 a year.
Annual hours are hours per day times 365. Energy is watts times annual hours divided by 1,000 times the bulb count, priced at your electricity rate, plus bulbs per year (bulb count times annual hours divided by bulb life) times the bulb price.
About 25,000 hours against about 1,000 hours in this calculator. At 3 hours a day that is roughly 23 years for an LED against roughly 11 months for an incandescent.
65.7 kWh at 3 hours a day, costing $11.17 at $0.17 per kWh before bulb replacements. Ten such bulbs use 657 kWh.
9.855 kWh at 3 hours a day, costing $1.68 at $0.17 per kWh before bulb replacements. Ten such bulbs use 98.55 kWh.
Yes, but it shrinks: $40.88 for incandescents against $6.31 for LEDs across 10 bulbs, a saving of $34.57 a year.
The totals rise to $208.05 for incandescents and $31.76 for LEDs, a saving of $176.29 a year. Higher power prices make LEDs pay back faster.
Because a 25,000-hour LED lasts many years, its cost is spread across years: 0.438 bulbs a year at 3 hours a day is the yearly share of one bulb's $5 price, not a purchase of part of a bulb.