How do you calculate UV dose in mJ/cm²?

Multiply measured irradiance in mW/cm² by exposure time in seconds. At 850 mW/cm² for 1.8 seconds you get 1,530 mJ/cm². The milliwatt and millijoule units align so no unit conversion is needed.

What is a good UV dose margin?

Aim for 110-130% of the datasheet target. In the worked example the delivered 1,530 mJ/cm² against a 1,200 mJ/cm² target gives a 127.5% margin, which leaves headroom for lamp aging without overcuring.

Why does peak irradiance matter separately from dose?

Some chemistries need a minimum peak irradiance to initiate cure at depth, while dose drives through-cure. Two settings can share the same dose but one may fail if peak irradiance is too low, so track both.

What is the maximum conveyor speed for my target dose?

Divide the effective cure-zone length by the required exposure time. With a 2 ft zone and a required 1.41 second exposure, max speed is 85 ft/min while still hitting the 1,200 mJ/cm² target.

UV dose vs cure — are they the same thing?

No. Dose is delivered energy; cure is the resulting crosslink state. Adequate dose usually produces cure, but temperature, oxygen inhibition, film thickness, and pigment loading can require more dose than the nominal datasheet value.

How does lamp aging affect my dose?

UV lamps lose output over their life, so an in-spec dose today can drop below target months later. That is why building 20-30% margin in matters — re-measure irradiance periodically with a radiometer rather than trusting run-hours.

Finishing calculator

UV Dose Calculator

UV dose is the total energy an ink, coating, or adhesive receives, measured in millijoules per square centimeter, and it is the single most predictive number for whether a part cures fully. Line engineers and finishing supervisors use it to translate a datasheet cure-dose target into real conveyor and lamp settings, because peak irradiance alone tells you nothing about total energy delivered. Get dose wrong and you get undercure (tacky surface, poor adhesion) or overcure (yellowing, embrittlement). This calculator also reports your margin against the required dose and the fastest conveyor speed that still hits target.

What this calculator does

Calculate UV dose from measured irradiance and exposure time, then compare it with the material cure-dose target and conveyor speed limit.
Use it for first-article setup, lamp-change checks, adhesive and coating validation, or any job where cure quality depends on dose at the part surface.
It multiplies measured irradiance by exposure time to get delivered UV dose, then compares that dose to the material's required dose and derives the maximum conveyor speed that still meets target.

Formula used

UV dose (mJ/cm²) = measured irradiance (mW/cm²) × exposure time (sec)
Dose margin (% of target) = calculated dose ÷ required dose × 100
Maximum conveyor speed = effective lamp cure-zone length ÷ required exposure time

Inputs explained

Measured irradiance at part: Use a calibrated radiometer reading at the actual cure surface, in the wavelength band your chemistry uses.
Exposure time under UV: For a conveyor, use dwell time through the effective cure zone. For a spot or flood cure, use lamp-on time at the part.
Material cure-dose target: Dose required by the adhesive, coating, ink, or resin data sheet after any internal process margin.
Effective lamp cure-zone length: Length along the conveyor where irradiance is high enough to count toward cure, not the full lamp housing length.

How to use the result

Use it when commissioning a UV line, qualifying a new coating, or diagnosing tacky or under-adhered parts after a lamp, reflector, or speed change.
Dose assumes irradiance stays constant across the exposure and ignores spectral match — a UVA-heavy datasheet dose is not interchangeable with a UVC lamp reading, so always use a radiometer band that matches the datasheet.

Common questions

How do you calculate UV dose in mJ/cm²? Multiply measured irradiance in mW/cm² by exposure time in seconds. At 850 mW/cm² for 1.8 seconds you get 1,530 mJ/cm². The milliwatt and millijoule units align so no unit conversion is needed.
What is a good UV dose margin? Aim for 110-130% of the datasheet target. In the worked example the delivered 1,530 mJ/cm² against a 1,200 mJ/cm² target gives a 127.5% margin, which leaves headroom for lamp aging without overcuring.
Why does peak irradiance matter separately from dose? Some chemistries need a minimum peak irradiance to initiate cure at depth, while dose drives through-cure. Two settings can share the same dose but one may fail if peak irradiance is too low, so track both.
What is the maximum conveyor speed for my target dose? Divide the effective cure-zone length by the required exposure time. With a 2 ft zone and a required 1.41 second exposure, max speed is 85 ft/min while still hitting the 1,200 mJ/cm² target.
UV dose vs cure — are they the same thing? No. Dose is delivered energy; cure is the resulting crosslink state. Adequate dose usually produces cure, but temperature, oxygen inhibition, film thickness, and pigment loading can require more dose than the nominal datasheet value.

Last reviewed 2026-05-12.