How to choose proper GSM for custom PP woven sacks
2026-08-20
GSM means grams per square meter. It tells you how thick and strong your PP woven sack fabric is.
Higher GSM makes bags stronger, but costs more.
Many buyers only check bag size and printing. They ignore GSM. This can cause broken bags, torn seams and lost goods during sea shipping, stacking and loading.
When you pick GSM for your custom bags, think about:
‑ How much weight the bag will hold
‑ What goods you will put inside
‑ How you transport and store the bags
‑ Whether you need BOPP film or PE inner liner
Suggested GSM for different uses
| GSM Range | Type | Load Weight | Main Use |
| 58‑60 GSM | Light duty | 10‑20 kg | Light grain, seeds, small farm goods |
| 60‑65GSM | Standard | 20‑35 kg | Rice, wheat, corn, animal feed, sugar, food‑grade export bags |
| 65‑70 GSM | Heavy duty | 35‑50 kg | Fertilizer, salt, chemicals, sea export with high stacking |
| 70‑85 GSM | Extra heavy | 50‑60 kg | Mineral sand, sharp goods, long outdoor storage (need UV treatment) |
Important note: BOPP film weight does NOT count towards base fabric GSM. Always confirm the base fabric GSM with your supplier to avoid quality problems.
What you need to consider
- Loading weight Heavy goods need higher GSM. For 50kg goods, fabric below 65‑GSM breaks easily during shipping.
- Type of goods Hard, sharp materials like sand and minerals need thicker fabric. Soft grain can use standard GSM.
- Sea export & stacking For shipments to South America, Middle East or Africa, bags sit under heavy stack pressure. Choose one higher GSM level to stop bags from breaking.
- Outdoor storage If bags stay outside for months, add UV protection. Sunlight will make PP bags brittle quickly without UV treatment. Higher GSM alone is not enough.
- Liner or BOPP film PE inner liner keeps goods dry. But it cannot make the bag stronger. A liner cannot replace thicker high‑GSM fabric.