ERP Migration & SelectionFree calculatorPDF, Excel, Word export

ERP Data Cutover Window Calculator

Cutover plans fail when the final load takes longer than the weekend. This calculator checks whether your volume, throughput and validation time fit the window you have.

Your numbers

Records to load in cutover

records

Include open transactions, balances and any master data not loaded earlier.

Throughput per stream

records/min

Measure this in a rehearsal, not from a vendor brochure.

Parallel streams

2 streams

Validation and reconciliation overhead

40 %

Planned full rehearsals

3 runs

Business cutover window

hours

Your results

Load plus validation

19 hrs

Window headroom

29 hrs

Negative means the plan does not fit.

Raw load time

833.3 min

Window utilisation

40.5%

Total rehearsal machine time

58 hrs

Assumes linear scaling across streams. Database locks and API limits usually flatten the gain, so confirm in a rehearsal.

Free, optional. Reopen it on any device.

Save results:

Load hours vs parallel streams

Sweeps Parallel streams from 1 to 8, holding your other inputs fixed.

Optional cutover runbook review

Have a second pair of eyes check your timings and rerun plan.

Optional. The tool and every export work without this. No spam.

Was this tool useful?

How to use it

Count only the records loaded during cutover. Master data, closed history and configuration should be loaded days earlier. Take throughput from your most recent rehearsal and enter the number of streams you actually ran. Keep utilisation under 70 percent so a failure can be rerun without missing go-live.

The method

Raw load minutes equal records divided by throughput times streams. Validation overhead scales the result, then dividing by 60 gives hours. Headroom is the window minus load hours, and utilisation is load hours as a percentage of the window. Rehearsal time is load hours times the number of full runs.

Common mistakes

Teams extrapolate from a small sample, forget validation, or assume eight streams give eight times the speed. Source system extract time, network transfer and index rebuilds also sit outside this formula, so add them as extra overhead. Treat a result near the window limit as a red flag.

Measure real throughput
Preload what you can
Plan a rerun budget
Include extract and index time

Frequently Asked Questions

How many rehearsals are enough?

Three full rehearsals is a common minimum: one to find errors, one to fix and time, one to prove the runbook. Complex multi-entity migrations may need more.