Polyester Resin Calculator
Work out your laminating resin quantities
Enter your area, mat weight and layers below for an instant resin, mat and catalyst estimate.
Common questions
What mat weight should I use?
450gsm is the standard choice for most general lay-ups. 300gsm is easier to wet out on tight curves and detail; 600gsm builds thickness faster on large flat areas but takes longer to fully saturate.
Why does catalyst dosage change with temperature?
Catalyst (MEKP) triggers the cure reaction, which runs faster in warm conditions and slower in cold ones. Using more catalyst in cold conditions keeps cure time reasonable; less in warm conditions avoids the resin curing too fast to work with.
Isophthalic vs standard resin — what's the difference?
Isophthalic resin costs more but gives better water and chemical resistance, making it the standard choice for marine, pool and tank applications. Standard resin is fine for most general projects.