There are 2 methods we use to calculate fabric quantities and the cutting orders for half drop pattern repeats. The calculator

1. Automatically calculates which method uses the least fabric.
2. Calulates the fabric quantity required
3. Creates a Cutting Diagram
4. Creates a Joining Diagram

There is a concise list of instructions for each method below. For more detailed information on half drop pattern repeats and the 2 methods please read HERE

2 important points:

1. The Calculator includes half a pattern repeat (PR) for positioning the pattern on your drops.(you may want to add an extra half PR to the total to give you a whole PR to position the pattern)
2. The calculator calulates both length and number of pattern repeats for the drops. When cutting the drops measure in pattern repeats it is important you cut the fabric at the correct position on the pattern.

This method rounds the fabric cut drop up to a whole number of pattern repeats so is the best method when the cut drop is at least half way into the last pattern repeat.

1. Calculate an Adjusted Cut Drop (ACD) using whole Pattern Repeats (PRs), rounding the cut drop up to the next whole PR.
2. Multiply the ACD by the number of drops and add one whole PR to calculate the total fabric frequired.
3. Use 1/2 PR to position the top of the first drop
4. Number the drops
5. Mark and cut the ODD drops all the length of the ACD, except cut the last ODD drop 1/2 PR longer.
6. Then cut all the EVEN drops the length of the ACD. (Note these ACDs will all start 1/2 a PR down on the pattern when compared to the ODD drops.)
7. Join the drops as in the "Joining Diagram"

More detail on this method >>

This method rounds the fabric cut drop up to the nearest half pattern repeat so is the best method when the cut drop is up to half way into the last pattern repeat.

1. Calculate the Adjusted Cut Drop (ACD) in whole pattern repeats (PRs), but round the fabric cut drop up to the next HALF PR.
2. Multiply the ACD by the number of drops and add half* a PR to calculate the total fabric required. Note:* Add a whole PR if you are making a pair of curtains with an odd number of drops.
3. Use up to 1/2 PR to position the top of the first drop.
4. Cut the Adjusted cut drops marking them alternately A then B. They will all be the same length unless you are making a pair of curtains with an odd number of drops, in which case cut the last drop (which will be an "A") half a PR longer. You will have included an extra half PR in your fabric qty calculation for this purpose.
5. Join the drops as in the "Joining Diagram"

More detail on this method >>

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