Corrugated Flute Take-Up Ratio Analyzer
Fluting medium length, and optionally medium weight, for any length of combined corrugated board, built for corrugator planners.
Take-up calculator
Take-up factor used: 1.44 (C-flute, US EPA example)
Numbers substituted
Fluting length = board length × factor = 1,000 m × 1.44 = 1,440 m
Per 1000 m of board = 1000 × 1.44 = 1,440 m
Weight lines appear when you enter a medium basis weight.
What the flute take-up factor means
The take-up factor is the length of fluted medium needed for each unit length of combined corrugated board, because the medium runs as a wave between the liners. According to the US EPA document Sample Calculation of the Postconsumer Fiber Content of a Corrugated Container, C-flute, a commonly manufactured corrugated board, has a take-up factor of approximately 1.44, so each foot of combined board has 1.44 feet of fluted medium.
This analyzer multiplies a length of combined board by that factor to give the fluting medium length. Add the medium basis weight and the board width to get the medium weight per square metre of board and the total medium weight. The 1.44 value is an example figure; confirm it with your mill data sheet before you plan a run.
How to use the analyzer
- Enter the board length in metres: the length of combined board you plan to run.
- Choose C-flute 1.44 (US EPA example), or choose Custom and type the take-up factor from your mill data sheet (1 to 2).
- Read the fluting medium length and the medium needed per 1000 m of board.
- Optional: enter the medium basis weight in g/m² and the board width in metres to get the medium weight per m² of board and the total medium weight in kg.
- Check the substituted formulas under the results to see every number used.
Formulas: fluting length = board length × factor; per 1000 m of board = 1000 × factor; medium weight per m² of board = basis weight × factor (g/m²); total medium weight = medium weight per m² × board length × width ÷ 1000 (kg).
Worked case: the EPA C-flute medium
The EPA example uses a medium of 26 lbs per 1000 square feet. With 1 lb per 1000 square feet = 4.882428 g/m², that is 26 × 4.882428 = 126.943 g/m².
Applying the C-flute take-up factor: 26 × 1.44 = 37.4 lbs per 1000 square feet, or 126.943 × 1.44 = 182.8 g/m² of board.
For 1000 m of board 1 m wide:
- Fluting length = 1000 m × 1.44 = 1,440 m of medium
- Total medium weight = 182.8 g/m² × 1000 m × 1 m ÷ 1000 = 182.8 kg
Enter 1000 m, C-flute, 126.943 g/m² and 1 m in the analyzer to reproduce these figures.
Board example from the same EPA page
The two linerboards of 42 lbs per 1000 square feet each count at a factor of 1.00, while the medium counts at the take-up factor.
| Layer | Basis weight (lbs per 1000 ft²) | Factor | Counted (lbs per 1000 ft²) |
|---|---|---|---|
| Linerboard | 42 | 1.00 | 42 |
| Medium | 26 | 1.44 | 37.4 |
| Linerboard | 42 | 1.00 | 42 |
| Combined board | 121.4 |
So the combined board is 42 + 37.4 + 42 = 121.4 lbs per 1000 square feet. This page computes the medium only.
Source: US EPA, Sample Calculation of the Postconsumer Fiber Content of a Corrugated Container.
Frequently asked questions
Which take-up factor should I use for C-flute?
Use 1.44. The US EPA sample calculation gives C-flute, a commonly manufactured corrugated board, a take-up factor of approximately 1.44, so each foot of combined board has 1.44 feet of fluted medium. Confirm it with your mill data sheet.
Why are no other flutes listed?
Only the EPA C-flute value is given on this page. For any other flute, choose Custom and enter the take-up factor from your mill data sheet.
How do I turn medium basis weight into weight per board area?
Multiply the medium basis weight by the take-up factor. For example, 125 g/m² × 1.44 = 180 g/m² of medium per square metre of combined board.
Does the analyzer give the whole board weight?
No. It computes the medium only. The EPA example adds the two linerboards at a factor of 1.00 each: 42 + 37.4 + 42 = 121.4 lbs per 1000 square feet.
Disclaimer
This analyzer gives an estimate only. It is not a substitute for your mill data sheet or for advice from a qualified engineer.