# Reference Numbers PAI assigns two reference numbers to every project, at two different points in the lifecycle. They're not duplicates — they serve different purposes, appear on different documents, and signal different stages of the work. --- ## Estimate Number When you create a project, PAI immediately assigns an estimate number, counting up from 001. By default it uses the prefix **E** (E001, E002, E003, and so on). You can change the prefix in **Settings → Company Settings**. Each prefix keeps its own count: switch from E to F and the next project is F001; switch back to E and numbering picks up where E left off. PAI never assigns the same number twice. The estimate number is the project's identity during the bidding phase. Each version adds a suffix — **E121-V01**, **E121-V02** — and the estimate number appears on estimate documents shared with clients. --- ## Project Number When an estimate version is approved, PAI assigns a project number, also counting up from 001. By default it uses the prefix **P** (P001, P002, and so on), and like the estimate prefix it can be changed in Company Settings. The project number signals that a bid has become a confirmed job. From then on PAI shows the project as **P068 (E119-V03)**: the project number leads, and the approved version's estimate number stays alongside it for reference. The project number is what you and your vendors cite going forward. If a different version is approved later, the project number moves to that version; the number itself doesn't change. --- ## Job Codes If your organization uses its own numbering system — for tracking jobs in an external accounting system, following a client's numbering convention, or any other reason — turn on **Custom Job Codes** in **Settings → Company Settings**. Job Codes are free-form identifiers (e.g., `JOB-2026-0421`). Each must be unique across the workspace; PAI won't save a code another project already uses. With Job Codes on, you can enter one in **Custom Job Code** when you create a project, or later in **Job Code** on the project's Dashboard. Once a project has one: - The Job Code becomes the project's **primary identifier**: it replaces the estimate and project numbers in the project's header and on client-facing documents - The E### and P### numbers stay on the project's Dashboard and still work in search > [!note] > Job Codes are optional per project even when the feature is on. Projects without one keep using their E### and P### numbers. --- ## Using Reference Numbers Estimate and project numbers are searchable from global search (**⌘K** / **Ctrl+K**) and from any project list filter. In organizations with large project volumes, searching by number is usually the fastest way to reach a specific project.