How do you calculate UV dose margin?

Divide measured dose by required dose and subtract 100%. With 1,560 mJ/cm² measured against a 1,200 mJ/cm² requirement, margin is 76.9% above target — well above a bare-minimum requirement.

What is a good UV dose margin?

Most lines aim for 15-30% at minimum with fresh lamps often at 50-80%. The example's 76.9% is comfortably high, but if your minimum acceptable margin is set to 20% the headroom output shows how far you are above or below it.

What does negative headroom mean?

Headroom is margin minus your minimum acceptable margin. If your minimum is set higher than the actual margin, headroom goes negative — a flag that measured dose does not meet your own process threshold even if it exceeds the raw datasheet target.

Why set a minimum acceptable margin above zero?

Because lamps keep decaying after each check. A minimum of 20% means you replace or intervene before dose reaches the datasheet floor, avoiding undercure between inspections rather than reacting after failures appear.

Dose margin vs cure margin — what's the difference?

Dose margin compares energy to the datasheet requirement. Cure margin can also fold in real-world factors like film thickness and oxygen inhibition. Dose margin is the measurable proxy you audit on the floor.

How often should I check dose margin?

Weekly to monthly depending on lamp duty cycle and part criticality. High-runtime lines lose margin faster, so more frequent radiometer checks catch the slide before it crosses your minimum.

UV Curing calculator

UV Dose Margin Calculator

UV dose margin is how far your measured dose sits above the material's required dose, expressed as a percentage, and it is the health check that keeps a UV line out of the undercure danger zone. Quality and process engineers track it because lamps decay continuously, so a line that passes at commissioning slowly loses margin until it fails. This calculator states the margin and compares it to a minimum you set, giving a clear pass or flag verdict. It turns a raw radiometer reading into a go/no-go decision on the floor.

What this calculator does

Compare a measured UV dose against the chemistry's required dose and see how much headroom (or shortfall) you have before lamp drift puts you under-cure.
Use it after a radiometer pass to decide whether a line can keep running until the next scheduled lamp service or whether a setpoint change is needed now.
It expresses measured dose as a percentage above the required dose and compares that margin to your minimum acceptable threshold, returning the headroom in percentage points.

Formula used

Margin (%) = (measured dose ÷ required dose) − 100%
Verdict = ✅ if margin ≥ minimum acceptable margin, ⚠ otherwise

Inputs explained

Required cure dose from datasheet:
Measured dose at part surface:
Minimum acceptable process margin:

How to use the result

Use it during routine radiometer checks and lamp-aging audits to decide whether the line still cures safely or needs a lamp swap.
Margin only reflects total energy — it does not catch spectral drift, peak-irradiance shortfalls for depth cure, or oxygen inhibition, so a positive margin is necessary but not always sufficient for full cure.

Common questions

How do you calculate UV dose margin? Divide measured dose by required dose and subtract 100%. With 1,560 mJ/cm² measured against a 1,200 mJ/cm² requirement, margin is 76.9% above target — well above a bare-minimum requirement.
What is a good UV dose margin? Most lines aim for 15-30% at minimum with fresh lamps often at 50-80%. The example's 76.9% is comfortably high, but if your minimum acceptable margin is set to 20% the headroom output shows how far you are above or below it.
What does negative headroom mean? Headroom is margin minus your minimum acceptable margin. If your minimum is set higher than the actual margin, headroom goes negative — a flag that measured dose does not meet your own process threshold even if it exceeds the raw datasheet target.
Why set a minimum acceptable margin above zero? Because lamps keep decaying after each check. A minimum of 20% means you replace or intervene before dose reaches the datasheet floor, avoiding undercure between inspections rather than reacting after failures appear.
Dose margin vs cure margin — what's the difference? Dose margin compares energy to the datasheet requirement. Cure margin can also fold in real-world factors like film thickness and oxygen inhibition. Dose margin is the measurable proxy you audit on the floor.

Last reviewed 2026-05-12.