Process tool
Tablet coating weight gain calculator
How much dry coating material a batch needs at a target percentage weight gain, including process loss.
- 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
Material to issue
1.553 kg
Includes 15% process loss
- Dry coating applied
- 1.35 kgWhat ends up on the tablets
- Tablets in the charge
- 90,000
- Coating per tablet
- 15 mg
- Coated tablet weight
- 515 mg
How this was worked out
- dry coating = 45 kg × 3% ÷ 100 = 1.35 kg
- material to issue = 1.35 kg × (1 + 15 ÷ 100) = 1.553 kg
- tablets = 45 kg ÷ 500 mg = 90,000
- per tablet = 1.35 kg ÷ 90,000 = 15 mg
Formula
dry coating (kg) = charge (kg) × weight gain (%) ÷ 100 material to issue = dry coating × (1 + process loss ÷ 100)
Why this number matters
Weight gain is how a coating run is specified and how it is signed off. You weigh the charge in, coat until the tablets have picked up the target percentage, and stop. Everything else, spray rate, pan speed, bed temperature, exists to get you there without a defect. The figure that matters on the shop floor is the second one, because you have to issue more material than ends up on the tablet.
Where it goes wrong
Process loss varies with pan design, spray gun setup and how well the run is controlled. Fifteen percent is a reasonable planning figure for a first trial, and your own runs will give you a better one within two or three batches.
Worked example
With tablet charge of 45 kg, target weight gain of 3 %, process loss of 15 % and core weight of 500 mg, the calculation gives:
- Dry coating appliedWhat ends up on the tablets
- 1.35 kg
- Material to issueIncludes 15% process loss
- 1.553 kg
- Tablets in the charge
- 90,000
- Coating per tablet
- 15 mg
- Coated tablet weight
- 515 mg
The arithmetic is 2 lines, shown beside the result above so it can be checked by hand: dry coating (kg) = charge (kg) × weight gain (%) ÷ 100; material to issue = dry coating × (1 + process loss ÷ 100).
Typical ranges
- Tablet charge(kg)Core weight loaded into the pan
- Target weight gain(%)2 to 4% film, 6 to 12% enteric
- Process loss(%)Spray drying and pan loss, usually 10 to 20%
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.
Typical weight gain by application
General guidelines. They vary with the formulation, the process and the finish you are after.
| Application | Typical weight gain |
|---|---|
| Film coating (standard) | 2 – 5% |
| Film coating (high opacity) | 5 – 8% |
| Enteric coating | 8 – 15% |
| Moisture barrier coating | 3 – 8% |
| Sugar coating | 20 – 60% |
| Seal and pre-coat | 1 – 3% |
| Taste mask coating | 3 – 8% |
| Sustained release coating | 5 – 15% |
Other calculators
- Coating dispersionWater or solvent needed to disperse a ready-mix powder at a given solids concentration.
- 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
- Enteric coating systemWeight gain is the acceptance criterion for an enteric coat: too little and gastro resistance fails.
- ECM-RP348, aqueous entericDeveloped against a stated weight gain, so the target is a specification rather than a habit.
- Coating dispersion and solids calculatorWater or solvent needed to disperse a ready-mix powder at a given solids concentration.
- 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.