What does it mean?
Practical completion is a contractual milestone concerning completion of the works, assessed under the relevant agreement. It is not simply a percentage obtained by dividing spent cost by budget. The milestone may affect possession, retention, insurance responsibilities and other project arrangements. The applicable contract, certification process and outstanding work determine its meaning on a particular job.
In practice
A project can have 99% of its forecast cost spent while a critical system remains unfinished. A cost percentage therefore cannot determine whether practical completion has been achieved.
Keep in mind
For a project record, note the document reference, revision and agreed measurement or contractual basis beside the quantity. Keep assumed information visibly separate from confirmed information. If two parties use different definitions or inclusions, resolve that difference before comparing amounts. These explanations are general estimating context; the wording of the applicable contract and its administration process must be checked for the particular job.