- Hypothetical source A lists 12 pieces and source B lists 14 for the same mark.
- Do not merge the two into 26; retain both references and resolve the discrepancy.
- Source revision, scope and reviewer decision belong with the quantity record.
Freeze a review copy
Export a CSV before changing an approved or shared input. Name the file with the project reference, date and revision. Choose Save snapshot to retain a named private calculator record. Private takeoff projects also autosave edits and retain revisions; confirm the Saved status before leaving. Your exported file is the record of the inputs and result at that moment.
Record the reason for a change
A new stock length, revised part dimension or altered appearance requirement can all change the plan. Note the source of the change and who must review it. Do not overwrite an earlier order quantity without determining whether material has already been purchased, cut or delivered.
- Preserve the old parts list and purchase list.
- List changed rows and the source of the change.
- Recheck every affected stock group.
Check the delta, then the whole
Comparing only total board counts can miss a critical length change. Review both the changed pieces and the full regenerated pattern, because packing can move unchanged parts between boards. Send the complete current record with a brief change note rather than expecting a recipient to reconstruct it from several messages.
Worked planning example
Revision 1 used four 40-inch rails; revision 2 requires four 44-inch rails. Even if the board count remains unchanged, the offcuts and pattern have changed. The new schedule must replace the old fabrication reference, with the dimension change highlighted.
Common questions
Does the site save versions automatically?
Private takeoff projects autosave after a short pause and retain revisions. Standalone calculator inputs require Save snapshot or export. Confirm the Saved status and keep portable exports for your own records.
Can I use the same file name?
You can, but a distinct date or revision makes it easier to identify the current record and retain the prior basis.
Evidence & limits
- Calculation method: dimensional arithmetic and conservative first-fit packing
- NIST PS 20-25 — measurement, tally and softwood size basis
Reviewed September 13, 2026. Sources support their stated technical principles; this site's workflows and hypothetical examples are not product tests, supplier approvals or independently reviewed project records.