Coating Weight Calculator
Calculate dry coating weight from wet application rate and solids content. Determine total coated sheet weight, water evaporation load, and coating cost.
About this calculator
Coating is applied to paper wet and then dried, so the number that actually matters for print quality and cost is the dry coating weight left behind, not the wet application rate you dial in at the coater. This calculator gets there by multiplying wet coating weight (g/m² per side) by the coating's solids content as a fraction — a coating applied at 25 g/m² wet with 65% solids leaves only 16.25 g/m² dry per side. That per-side figure is then multiplied by sides coated (1 for C1S, 2 for C2S) to get total dry coating, which is added to the base uncoated sheet weight to give the finished coated sheet's GSM, alongside what percentage of that total weight the coating itself represents.
The calculator also flags a practical drying-load number: the water fraction of the wet coating (1 minus solids content) that must be evaporated per side, scaled to both sides if coated on two — a heavier wet application or lower-solids formulation both increase the drying burden even at the same dry coating weight. Coating cost is converted to a cost per 1,000 m² basis using your dry coating material cost per kilogram. Finally, the calculator classifies the result against standard industry bands: under 5 g/m²/side is essentially trace, 5-12 is lightweight-coated (LWC), 12-20 is medium-weight (MWC), and above 20 is heavy or art-paper coating.
Inputs
Results
Dry coating/side (g/m²)
16.25
How to Use This Calculator
- Enter the base sheet weight (GSM) of your uncoated paper.
- Input the wet coating applied per side (g/m²) and solids content (%) from your formulation.
- Set the number of sides coated — 1 for C1S, 2 for C2S.
- Enter the coating material cost per kilogram.
- Review Dry Coating per Side, Coated Sheet GSM, Water to Evaporate, and Cost per 1,000 m².
How the result changes with Wet coating (g/m²/side)
| Wet coating (g/m²/side) | Dry coating/side (g/m²) |
|---|---|
| 13 | 8.45 |
| 19 | 12.35 |
| 38 | 24.7 |
| 63 | 40.95 |
What each input means
- Base sheet (GSM)
- Uncoated base sheet weight in grams per square meter.
- Wet coating (g/m²/side)
- Wet coating applied per side in g/m².
- Coating solids (%)
- Solids content of the coating suspension (typically 55-70%).
- Sides coated
- 1 = C1S (one side), 2 = C2S (both sides).
- Coating cost ($/kg)
- Cost of dry coating material per kilogram.
What each result means
- Dry coating/side (g/m²)
- Dry coating weight deposited per side.
- Total dry coating (g/m²)
- Total dry coating weight on the sheet (both sides if C2S).
- Coated sheet (GSM)
- Total weight of the finished coated sheet.
- Coating % of sheet
- Coating weight as percentage of total sheet weight.
- Water to evaporate (g/m²)
- Total water that must be evaporated during drying.
- Cost per 1000 m² ($)
- Coating material cost per 1,000 square meters of paper.
- Category
- 0 = Trace, 1 = LWC (light), 2 = MWC (medium), 3 = Heavy/Art.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersBase sheet (GSM) = 70, Wet coating (g/m²/side) = 25, Coating solids (%) = 65, Sides coated = 2 = 5 input(s) provided
- Calculate Dry coating/sideDry coating/side = wetCoatingGSM * (solidsPct / 100)16.25 = 16.25
- Calculate Total dry coatingTotal dry coating = dryCoatingPerSide * sidesCoated32.5 = 32.5
- Calculate Coated sheetCoated sheet = baseSheetGSM + totalDryCoating102.5 = 102.5
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why is the dry coating weight so much lower than the wet application rate I enter?
Dry coating weight equals wet coating weight (g/m² per side) times solids content as a fraction — so a coating applied at 25 g/m² wet with 65% solids leaves only 16.25 g/m² dry per side, since the rest is water that evaporates during drying. The calculator always reports the dry figure because that's what actually remains on the sheet and affects print quality.
How does coating one side (C1S) versus both sides (C2S) change the results?
Sides coated multiplies the per-side dry coating figure directly: total dry coating equals dry coating per side times 1 for C1S or 2 for C2S. The same multiplier applies to total water evaporated, so switching from C1S to C2S at the same wet application rate and solids content doubles both the coating weight added to the sheet and the drying load.
What's the relationship between solids content and the water I need to evaporate?
Water per side is the wet coating weight times one minus solids content as a fraction, so a lower-solids formulation leaves more water to evaporate at the same wet application rate, increasing the drying burden even when the dry coating weight itself matches a higher-solids formulation applied at a correspondingly lower wet rate.
What do the coating category numbers mean?
They classify dry coating weight per side against standard industry bands: under 5 g/m² per side is trace or essentially uncoated, 5-12 is light-weight coated (LWC), 12-20 is medium-weight coated (MWC), and above 20 is heavy or art-paper coating. These thresholds are fixed inside the calculator and reflect common paper-industry terminology rather than a value you configure.
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