Why is cost per operating hour the headline?

Because a per-swap total cannot be compared with anything. The hourly figure sits beside energy on a per-part line, ranks lamps with different lives correctly, and annualizes with one multiplication.

What happened to the scrap risk allowance?

It was removed deliberately. It was a lump with no stated derivation; scrap risk is a defect rate times a part cost, derived on the rework page. Rated life took the input slot.

Do I divide by lamps times life?

No. The lamps run at the same time, so a four-lamp swap buys one lamp-life, not four. Dividing by lamps times life understates the hourly cost by the lamp count.

Is it worth paying more for longer-life lamps?

Compute it with the hourly row. A lamp costing 38% more with 75% more life is cheaper to run and needs fewer swaps. Longer life only pays if the lamps achieve it on your system.

UV Curing calculator

UV Lamp Replacement Cost Calculator

Price a lamp change properly and put the total in a unit you can compare. Enter the lamp count, unit price, downtime cost and rated life; the hourly figure is the answer.

What this calculator does

Price a lamp swap with its downtime, and convert it into cost per operating hour.

Formula used

Lamp material cost = lamp count × unit price
True cost per swap = material cost + downtime cost
Cost per operating hour = swap cost ÷ rated life
Cost per lamp = swap cost ÷ lamp count
Downtime share = downtime ÷ swap cost × 100

Inputs explained

Number of Lamps in This Swap: Lamps changed in one event, normally all together.
Unit Price per Lamp: Delivered price of one lamp, including freight.
Downtime Cost During the Swap: Lost contribution plus labor while the line stops.
Rated Lamp Life: Hours the new lamps are expected to give.

How to use the result

Best suited to comparing lamps that differ in price and life, putting lamp cost beside energy per part, building the mercury side of a retrofit case.
Ignores decay across lamp life: the last hours deliver the least dose. Excludes reflectors, quartz sleeves, filters and seals. Says nothing about regulated mercury disposal costs.

Common questions

Why is cost per operating hour the headline? Because a per-swap total cannot be compared with anything. The hourly figure sits beside energy on a per-part line, ranks lamps with different lives correctly, and annualizes with one multiplication.
What happened to the scrap risk allowance? It was removed deliberately. It was a lump with no stated derivation; scrap risk is a defect rate times a part cost, derived on the rework page. Rated life took the input slot.
Do I divide by lamps times life? No. The lamps run at the same time, so a four-lamp swap buys one lamp-life, not four. Dividing by lamps times life understates the hourly cost by the lamp count.
Is it worth paying more for longer-life lamps? Compute it with the hourly row. A lamp costing 38% more with 75% more life is cheaper to run and needs fewer swaps. Longer life only pays if the lamps achieve it on your system.

Last reviewed 2026-10-01.