Plan the move to one system.
Tell us what you run and what your calendar looks like. Get a phased plan that keeps the accounting cutover off your year-end and out of peak season, plus the risks and exports to handle first. Useful whichever software you pick.
Your phased migration plan
Illustrative durations from the rules of thumb explained below. Change any input and the plan redraws.
- Total timeline
- —
- Accounting go-live
- —
- Systems in scope
- —
- Approach
- —
- Peak season
- Fiscal year-end
- Accounting go-live
- Waiting for a clean period boundary
Risk checklist
Tailored to what you ticked. These are the things that break cutovers.
Data to export now
Worth doing even if you never switch. Exports are also what any cutover reconciles against.
This planner works for any system you move to. os.construction can import project data from another project management system today (preview, run with our team), and schedules import from MS Project XML. Accounting-system imports are planned. Read importing data, or tell us your stack when you start a free trial.
Sample inputs: a mid-size GC with 14 active jobs, December year-end, June to August peak (illustrative).
How the plan is built
These are illustrative rules of thumb, not a quote or a promise. Real timelines depend on data quality, who does the work and how many decisions are still open. Use the plan to start the conversation and to see where the calendar pushes you.
Durations (weeks)
Team factor = 1.3 (≤3 in office) · 1.1 (≤10) · 1.0 (≤30) · 1.15 (more)
Phase 0 prep = (2 + 0.5 × systems + 0.5 × critical systems
+ 2 if accounting + 1 if PM) × team factor, min 3
Phase 1 pilot = 6 (+2 with a field app) phased: one pay app cycle
3 (+1 with a field app) big-bang: dry run on a copy
Phase 2 = 8 + active jobs ÷ 8 phased: new jobs start new
(2 + active jobs ÷ 6) × team big-bang: load every open job
Phase 3 cutover = 4 + 2 if accounting + 2 if payroll
Phase 4 history = (3 + 0.25 × years of history per system, capped at 10
+ 3 if BI) × team factor, min 3Picking the accounting go-live
- Go-live is always the 1st of a month, after the prior month is closed in the old system. Mid-month cutovers split a period across two ledgers.
- Earliest go-live: halfway through Phase 2 when phased (some new jobs are running), or after every open job is loaded when big-bang.
- Avoid year-end skips the last month of your fiscal year and the two after it, when year-end close, audit or review prep and 1099s land.
- Peak season: the go-live month and the month after it (your first close in the new system) must both be outside peak months.
- Fiscal year start is the other school: a clean opening year with no partial-year history to reconcile. It works when your year-end close is fast.
Phased or big-bang
Phased means new jobs start on the new system while existing jobs finish where they are. Nothing is migrated mid-job, at the cost of running two systems for a while. Big-bang moves everything on one date: one system sooner, but every open job has to reconcile on the same weekend.
The risk checklist and export lists change with what you tick. They're general industry practice, not legal or tax advice: check payroll and year-end timing with your CPA.
Read next
One system, so the next move is the last one.
Project and project-financial tools are live. Import from another project management system is in preview: directory, RFIs, submittals, punch, observations, daily logs, documents, prime contracts and commitments, with a dry run first. Accounting CSV import has limited scope; vendor sync and historical AR aging are unavailable. Verify mappings and historical coverage before planning a cutover. Tell us your stack.