Process tool
Coating dispersion and solids calculator
Water or solvent needed to disperse a ready-mix powder at a given solids concentration.
- Runs in the browserNothing is submitted anywhere
- Working shownCheck every line by hand
- Plant figuresThe bands our grades run in
- Free, no sign-inNo account, no email
Written by the Rglax Pharma technical team, who formulate and manufacture every grade named on this calculator at our WHO-GMP works in Tahliwal, Una (drug manufacturing licence NNZ/23/238). Reviewed 3 September 2026. Licences and certificates.
Result
Total dispersion
10.333 kg
- Vehicle to add
- 8.783 kgPurified water or solvent
- Vehicle volume
- 8,783 ml
- Dispersion ratio
- 1 : 5.67powder to vehicle by weight
How this was worked out
- total dispersion = 1.55 kg ÷ (15 ÷ 100) = 10.333 kg
- vehicle = 10.333 − 1.55 = 8.783 kg
- volume = 8.783 kg × 1000 ÷ 1 = 8,783 ml
Formula
total dispersion (kg) = powder (kg) ÷ (solids % ÷ 100) vehicle = total dispersion − powder
Why this number matters
A ready-mix grade is supplied dry and dispersed on your side. The solids concentration you choose is a trade. Higher solids means less water to evaporate and a shorter run, but a thicker dispersion that is harder to pump and easier to block a gun with. Lower solids sprays cleanly and takes longer. Most aqueous work sits between 12 and 20 percent.
Where it goes wrong
Disperse under moderate shear and let the dispersion stand long enough for entrapped air to come out before spraying. Air in the line reads as spitting at the gun and shows up on the tablets as spray marks.
Worked example
With coating powder of 1.55 kg, solids concentration of 15 % w/w and vehicle density of 1 g/ml, the calculation gives:
- Total dispersion
- 10.333 kg
- Vehicle to addPurified water or solvent
- 8.783 kg
- Vehicle volume
- 8,783 ml
- Dispersion ratiopowder to vehicle by weight
- 1 : 5.67
The arithmetic is 2 lines, shown beside the result above so it can be checked by hand: total dispersion (kg) = powder (kg) ÷ (solids % ÷ 100); vehicle = total dispersion − powder.
Typical ranges
- Coating powder(kg)From the weight gain calculator
- Solids concentration(% w/w)12 to 20% aqueous, 5 to 12% solvent
- Vehicle density(g/ml)1.00 water, about 0.79 IPA
These are the bands our grades were developed in at Tahliwal. A run outside them is not wrong, but it is a run the published parameters no longer describe.
Other calculators
- Coating weight gainHow much dry coating material a batch needs at a target percentage weight gain, including process loss.
- Spray rateSpray rate per gun and total run time from your dispersion quantity and available process window.
- Pan speedTangential bed velocity from pan diameter and RPM, with the range most film coating runs sit in.
- Drying capacityHow much water your inlet air can actually carry away, and the spray rate that supports.
- Dispersion vesselVessel volume, diameter and impeller size for the dispersion quantity you are making.
- Surface area and build-upSurface area per tablet and coating build-up in mg per square centimetre, which is how enteric coats are specified.
Every grade page carries the process parameters it was developed on, so you can start from a known point rather than a calculated one. Browse the grades.
Read next
- Film coating systemSolids loading is what a film coat is made up to before a gun is opened.
- AQ-Z Wb, aqueous film coatSupplied ready to disperse at a stated solids, which is where this figure starts.
- Tablet coating weight gain calculatorHow much dry coating material a batch needs at a target percentage weight gain, including process loss.
- Coating spray rate calculatorSpray rate per gun and total run time from your dispersion quantity and available process window.
- Coating pan speed and tangential velocity calculatorTangential bed velocity from pan diameter and RPM, with the range most film coating runs sit in.
- Coating defects, and what causes themWhat the bed looks like when this number is wrong, and which parameter to move.
Need a second opinion
Talk to our technical team.
Send the core, the coater and the target and we will tell you what we would run, and which grade we would run it with.
From the calculation to the pan.