Polyaspartic System Calculator

Size a whole polyaspartic system coat by coat, each at its own solids and target thickness, and check the coats actually add up to the system thickness the job is specified at.

Does Your System Add Up to the Spec?

Enter the floor area and then, for each coat, the solids by volume and the dry film thickness that coat is meant to finish at. You get real coverage and volume per coat, the wet film to set your gauge to, kits to buy, and the system thickness those coats actually build. It seeds no product data: polyaspartics run from roughly two thirds solids to a hundred percent, and that difference alone moves the order by a third.

Solids and thickness come off your data sheets. Polyaspartics run from roughly two thirds solids to a hundred percent, and that difference is worth a third of the order, so this tool ships no defaults and asks you for each product’s figures. Leave a coat blank if your system does not use it.

The Floor

The area, and the finished system thickness you are working to.

Units
The area every coat goes over. Not sure? Work it out with the Area Calculator.
The finished dry film thickness the job is specified at. Enter it and the calculator checks whether the coats below actually add up to it.
What stays in the bucket, on the roller and in an open slab. 10% is a common starting point rather than a measured figure, and it applies to every coat.

The Coats

Each coat is its own product with its own solids content. That is the whole reason a system cannot be sized from one coverage rate.

Base Coat

By volume, not by weight. The two are different numbers and data sheets print both.
What this coat is meant to measure once it has cured. The calculator adds these up into the system thickness.
The made up volume of one kit, so the tool can round to whole kits. Leave blank to see volume only.

Second Coat (optional)

By volume, not by weight. The two are different numbers and data sheets print both.
What this coat is meant to measure once it has cured. The calculator adds these up into the system thickness.
The made up volume of one kit, so the tool can round to whole kits. Leave blank to see volume only.

Topcoat

By volume, not by weight. The two are different numbers and data sheets print both.
What this coat is meant to measure once it has cured. The calculator adds these up into the system thickness.
The made up volume of one kit, so the tool can round to whole kits. Leave blank to see volume only.

Enter the floor area, then the solids content and target dry film thickness for at least one coat, to see the system.

How the Polyaspartic System Calculator Works

  1. Choose imperial or metric
  2. Enter the floor area, and the finished system thickness the job is specified at if it has one
  3. For each coat, enter the solids by volume and the dry film thickness that coat should finish at
  4. Add each product's kit size to round the volume up to whole kits
  5. Leave any coat blank if your system does not use it
  6. Read the system thickness against your spec, then the volume and wet film for each coat

Examples

Scenario500 ft² garage, two coat system, 10% lossInputBase 90% solids at 6 mil · topcoat 85% solids at 4 milResult10 mil system · 3.94 gal total
ScenarioThat same stack, priced coat by coatInputBase in a 3 gal kit · topcoat in a 2 gal kitResult2.31 gal base, 1 kit · 1.63 gal topcoat, 1 kit
ScenarioThe same two coats against a 20 mil specificationInput6 mil plus 4 mil, and a spec asking for 20ResultShort of the spec by 10 mil
ScenarioThe same 10 mil floor, built from one product insteadInputAt 70% solids against at 100% solidsResult4.95 gal against 3.46 gal
Scenario45 m² metric job, base 150 µm plus topcoat 100 µmInput90% solids base · 85% solids topcoat · 10% lossResult250 µm system · 14.22 L total

Frequently Asked Questions

How do I work out how much polyaspartic a system needs?

One coat at a time, because each coat is a different product. For each one, the solids by volume and the dry film thickness you want give you a coverage rate, the coverage rate and the area give you a volume, and a loss allowance turns that into what you actually buy. Add the coats together and you have the system. A 500 ft² garage with a 90% solids base at 6 mil and an 85% solids topcoat at 4 mil comes to 2.31 gal and 1.63 gal, so 3.94 gal in total, and it builds a 10 mil system. Enter your own products above: those solids figures are round numbers chosen to show the arithmetic, not a product spec.

Why can I not just use one coverage rate for the whole system?

Because a coverage rate belongs to one product at one thickness, and a system is two or three products at different thicknesses. A base coat built for film and a topcoat built for wear rarely share a solids content, and they are almost never applied at the same thickness. Averaging them gives a number that describes nothing you are actually buying. That is why this calculator asks per coat, and why the flake system calculator, which takes a coverage rate per layer, answers a different question.

What is the system thickness, and why does my loss allowance not change it?

The system thickness is the sum of the coats' dry film thicknesses, and it is what a specification means when it asks for a 20 mil system. A loss allowance changes how much liquid you buy. It does not change how thick the finished floor is, because the material lost is the material that never reached the floor. Two coats at 6 mil and 4 mil build a 10 mil system whether your loss allowance is 5% or 40%, and if the spec asks for 20 you are 10 mil short no matter how much you order. The calculator says so rather than quietly closing the gap.

What wet film thickness should I apply?

The dry thickness divided by the solids fraction, which is always more than the number you are aiming for unless the product is 100% solids. A 90% solids product aimed at 6 mil dry needs 6.67 mil wet. At 70% solids the same 6 mil dry needs 8.57 mil wet. Wet film is the only thickness you can actually control while the coat is still going down, so it is the number your gauge should be set to. Setting the gauge to the dry figure is one of the most common ways a system finishes under spec.

How much difference does solids content really make?

For a finished thickness, volume scales exactly inversely with solids, so it makes more difference than almost anything else on the data sheet. The same 500 ft² floor finished at 10 mil takes 3.46 gal of a 100% solids product and 4.95 gal of a 70% solids one, which is 42.9% more liquid for an identical floor. Halve the solids and you buy exactly twice the material. This is why two products quoted per gallon are not comparable until you work out what each one costs per finished floor.

Does this calculator size the flake broadcast too?

No, and deliberately. Flake is sized by the area one pound covers, not by solids and film thickness, so it is a different calculation with a different input. The Flake Broadcast Calculator does it properly and this tool links to it. Building a second, worse copy of it here would mean two tools that can disagree about the same job.

Why does the calculator not have a product list?

Because the solids content is the single number that decides the order, it varies enormously across polyaspartics, and a default nobody can cite would quietly answer the question you came here to ask. Solids by volume is printed on the data sheet. Read it for the product you are actually buying, and check it is solids by volume rather than by weight, because sheets print both and they are different numbers.

Can I use this for epoxy or polyurethane instead?

Yes. Nothing in the arithmetic is specific to polyaspartic chemistry: it is solids, thickness and area, and that is true of any coating sold by volume. The tool is named for polyaspartics because a polyaspartic system is where the coat by coat question comes up most, since the fast recoat windows mean the whole stack often goes down in one day. If you are sizing a single product over several identical coats, the Film Thickness and Coverage Calculator is the simpler tool.

Important Notes

  • Solids by volume, not by weight. Data sheets print both and they are different numbers
  • The system thickness is a plain sum of the coats, and a loss allowance never changes it
  • Wet film is the only thickness you can control on the floor, and it is always thicker than the dry target
  • Kits are not totalled across coats, because two coats are two different products
  • Volume scales exactly inversely with solids, so halving solids doubles the liquid for the same floor
  • Flake broadcast quantity is sized by area per pound and belongs in the flake calculator
  • Minimum and maximum thickness per coat are product limits and live on your data sheet, not here
Film Thickness and Coverage CalculatorThe single coat version of the same arithmetic, with an inverse mode to audit a coat already down.Polyaspartic Cure Time CalculatorRecoat windows and cure times at your temperature, which is what decides whether the stack fits in one day.Flake Broadcast CalculatorFlake quantity for a broadcast system, sized by area per pound rather than by solids.Epoxy Coverage CalculatorStart from a coverage rate off the data sheet instead of deriving one from solids.Square Meter & Square Foot CalculatorWork out the floor area before you size any of the coats.
How Much Polyaspartic Do You NeedA polyaspartic floor is a stack of different products at different thicknesses, so no single coverage rate describes it. Size it coat by coat.

Why a System Cannot Be Sized Like a Coat

Every quantity tool for coatings answers the same question, which is how much liquid it takes to leave a given thickness on a given area. What changes between them is where the coverage rate comes from. A coverage calculator takes it off the data sheet. A film thickness calculator derives it from solids and a target thickness. Both then assume every coat is the same, and for one product applied twice that is perfectly true. A system breaks that assumption, because the coats are different products chosen for different reasons: a base coat picked for how it wets and builds, a topcoat picked for how it wears. They rarely share a solids content and they are almost never applied at the same thickness, so a single rate averaged across them describes nothing you can buy. Sizing per coat also surfaces the two things a single number hides. The first is the wet film, which is the only thickness you can control while the coat is going down and which is always thicker than the dry target at anything under 100% solids. The second is the system thickness, which is the plain sum of the dry coats and the figure a specification is written against. A loss allowance raises what you order and never touches it, so a stack that comes up short stays short however much material you buy.