What is the Corrugated Board Calculator?
Corrugated board is made of flat liners and wavy flutes. Flutes use more paper than their flat area because of the waves, measured by the take-up factor (about 1.4–1.5 for B and C flutes). The corrugated board calculator combines each paper's GSM to give the board's total GSM, thickness and weight.
Use the GSM in the Box Weight Calculator or the strength estimate in the Corrugated Box Calculator.
How to use the Corrugated Board Calculator
- Choose 3, 5 or 7 ply.
- Enter each liner and flute paper GSM.
- Choose the flute type (A, B, C, E).
- Read combined GSM, thickness and weight.
Formula
Combined GSM = Σ liner GSM + Σ (flute GSM × take-up factor)
Example
3-ply with 150 GSM liners and a 120 GSM C-flute (take-up 1.45): 150 + 150 + 120 × 1.45 = 474 GSM, about 4 mm thick.
Flute types
| Flute | Thickness | Take-up |
|---|---|---|
| A | 4.5–5 mm | 1.50 |
| C | 3.5–4 mm | 1.45 |
| B | 2.5–3 mm | 1.35 |
| E | 1.2–1.6 mm | 1.25 |
Related packaging and shipping tools
Packaging decisions are connected: the box size sets the volumetric weight, which sets the courier bill, and the carton size decides how many fit on a pallet or in a container. These related calculators help with the next step:
- Box size calculator: inside and outside box dimensions.
- Box volume calculator: volume in cm³, litres, CBM and ft³.
- Box weight calculator: empty carton weight from GSM.
- Corrugated box calculator: GSM and BCT strength.
- Cardboard sheet calculator: RSC blank size and sheet yield.
Frequently asked questions
What is combined GSM?
The total weight per square metre of all papers in the board.
What is a take-up factor?
How much more paper a flute uses than its flat area.
What is the difference between 3-ply and 5-ply?
3-ply has one flute (single wall); 5-ply has two (double wall) and is much stronger.
Which flute is best for shipping?
C flute for general shipping; BC double wall for heavy goods.
Does starch glue add weight?
Yes, about 10–20 GSM; add it if you want precise weights.
Is the Corrugated Board Calculator free to use?
Yes. The Corrugated Board Calculator on Custom Converter is completely free, with no sign-up, no daily limit and no watermark.
Does the Corrugated Board Calculator work on mobile phones?
Yes. It is built mobile-first and works on Android phones, iPhones, tablets and computers in any modern browser, with no app to install.