How could I crete and invoice template to include (1)a column for number of pieces (2)a column for length of each piece and (3)a calculated colum for total feet?

You can not do that in QBO

you need an outside invoice program, check the app store to see if there is anything that can do what you want

https://apps.intuit.com/app/apps/home

You can turn on Unit of Measure if you're using QuickBooks Premiere and Enterprise, fombyhardin.

Turning it on will automatically add a column in your template for Quantity (number of pieces), U/M (length of each piece), and Amount (total calculated amount for all pieces).

Here's how to activate the feature:

1. Go to the Edit menu and select Preferences.
2. Select Items and Inventory in the left-hand side.
3. Proceed to the Company and Preferences tab.
4. Click the drop-down list for Unit of Measure, then select Multiple U/M Per Item.
5. Click OK.

Once done, go to your Item List and assign a unit of measure to the products that you're selling. Here's how:

1. Go to the List menu and select Item List.
2. Double-click on the name of the item to open the edit window.
3. Click the drop-down list for Unit of Measure and select Add New.
4. Follow the succeeding prompts and enter the required details.

Once set up, create a sample invoice to using the item that you've set up. Please see this article about that talks about this feature for additional details: Use Single And Multiple Units Of Measure For Items.

You can also add a reply below if you need more help when creating invoices and assigning units of measure.

You can do that with a 3rd-party calculation add-on like FormCalc SST for QuickBooks or CCRQInvoice.

First, you'd add two custom columns (in the Item list), No. of Pieces, and Length per Piece. Then customize the form to include those two columns...that's where you'll enter the Pieces & Lengths on the form.

Second, rename the Quantity column to be something like Total Length.

Third, use the calculation add-on to multiply Pieces * Length and put the result in the Total Length field on each row.

Fourth, if using FormCalc SST, add an Item below all other Item rows on the form, to be a "trigger Item" to tell FormCalc SST to sum the Total Length column and display that total on the form.