How the Plastic Granule Converter Works
The Plastic Granule Converter divides resin pellet mass by pellet bulk density. The default 0.58 kg/L fits polyethylene (PE) and polypropylene (PP) pellets.
Pick the polymer
Choose PE, PP, PS, ABS, PET, PVC or nylon from the table.
Enter the bulk density
Use the supplier data sheet value or the table.
Enter the mass
Type the bag, octabin or silo mass in kilograms.
Read the volume
Size dryers, hoppers and silos from the liter result.
Plastic Granule Converter Formula
The plastic granule formula is V = m ÷ ρbulk. Pellet bulk density runs about 55–65% of solid polymer density.
- ρbulk
- Bulk density of pellets, kg/L
- ρpolymer
- Solid polymer density, kg/L
Worked Examples
- 25 kg bag of PP: 25 ÷ 0.54 = 46.3 L.
- 1 t octabin of HDPE: 1,000 ÷ 0.58 = 1,724 L.
- Dryer hopper: 50 kg/h of PET × 4 h residence = 200 kg ÷ 0.85 = 235 L.
Plastic Granule Converter Conversion Table
1 tonne of polyethylene pellets fills about 1,724 liters. The table lists 8 polymers.
| Polymer | Solid Density (kg/L) | Pellet Bulk Density (kg/L) | Liters per 25 kg Bag | m³ per Tonne |
|---|---|---|---|---|
| PP (polypropylene) | 0.905 | 0.54 | 46.3 | 1.85 |
| LDPE | 0.920 | 0.56 | 44.6 | 1.79 |
| HDPE | 0.955 | 0.58 | 43.1 | 1.72 |
| PS (polystyrene) | 1.050 | 0.62 | 40.3 | 1.61 |
| ABS | 1.050 | 0.63 | 39.7 | 1.59 |
| Nylon 6 (PA6) | 1.140 | 0.68 | 36.8 | 1.47 |
| PET | 1.380 | 0.85 | 29.4 | 1.18 |
| PVC compound | 1.400 | 0.75 | 33.3 | 1.33 |
What is a Plastic Granule Converter?
A Plastic Granule Converter is a calculator that converts plastic resin pellet weight into volume for hoppers, dryers and silos.
Resin producers cut molten polymer into pellets 2–5 mm across. Injection molders and extruders buy pellets by the tonne but feed them by volume through hoppers.
Regrind from crushed parts packs looser than virgin pellets, often 0.35–0.45 kg/L. Mixing regrind into a hopper lowers the bulk density of the blend.
What are the Uses of a Plastic Granule Converter?
There are 4 main uses of a Plastic Granule Converter.
Dryer sizing
Molders size desiccant dryers from throughput and residence time.
Silo planning
Plants size silos for bulk truck deliveries.
Masterbatch dosing
Technicians set volumetric doser rates.
Recycling logistics
Recyclers convert bale and regrind weights into volume.