The quick answer
Go to Setup > Accounting > Inventory Costing Preferences. Change Schedule Inventory Costing to Based on custom schedule, set Earliest Custom Schedule Start Time (10:00 pm in this example) and Latest Custom Schedule Start Time (4:00 am), check Respect Inventory Costing Time Restrictions on Weekends if costing should not start on weekends, and click Save. The two times limit when a costing run may start. They do not make costing faster, and transactions entered during the day still save.
Inventory costing is the background process that recalculates item cost, inventory value and cost of goods sold after inventory transactions. If it competes with the people posting receipts and shipments all day, you can ask NetSuite to start it only after hours. This guide sets that up on the Inventory Costing Preferences page and checks the saved result. It does not show a costing run.
Person and operating-company names in the screenshots are fictional example data. Use your own account and values.
Before you start
You need an Administrator role, or a role that can open Inventory Costing Preferences, on an account with the Inventory feature. The page is account-wide. Everyone sees the effect of what you change, so check three things first.
Note the current value of Schedule Inventory Costing. In the example it is After Transaction Entry. Available choices can vary by account and release, and NetSuite may not offer After Transaction Entry again after you move away from it. Plan for that before you save.
Check what depends on costs being final right away: scripts, workflows, integrations and reports that read an item's cost or inventory value right after a transaction saves. Also check whether an accounting period is about to close and how many transactions are waiting to be costed. Until the next permitted run those transactions use an estimated cost, and the related accounting can be adjusted when the run completes. Do not close a period while required costing is still running.
Treat the time zone the two times use, the way a window that starts on Friday evening behaves under the weekend restriction, and how long a run takes at your volume as things to test in your own account with a low-risk item.
01. Open Inventory Costing Preferences
Click Setup in the navigation bar, point to Accounting, and click Inventory Costing Preferences in the Preferences group. Schedule Inventory Costing shows After Transaction Entry. The two start-time lists and the weekend checkbox are greyed out because they only apply to a custom schedule. Two other preferences sit below them, Use Cost Estimate for Negative Inventory and Use the Exact Cost for Linked Returns. This walkthrough leaves both alone.
02. Choose a custom schedule
Open the Schedule Inventory Costing list. It offers After Transaction Entry, Based on custom schedule and Every Hour. Select Based on custom schedule. The Earliest Custom Schedule Start Time and Latest Custom Schedule Start Time lists and the weekend checkbox become editable. Review the values the account fills in before you change them. In the example they are 6:00 pm and 6:00 am, an evening-to-morning pair.
03. Set the overnight window
Open Earliest Custom Schedule Start Time and select 10:00 pm. Open Latest Custom Schedule Start Time and select 4:00 am. In the example account each list shows five rows and opens on its current value, so scroll to reach the time you want. Read the two values as one overnight start range: a costing run may start from 10:00 pm until 4:00 am the next morning. The form accepted this pair, but accepting values on a form does not prove how a saved range behaves, so verify the first run. The labels both say Start Time. They limit when a run may start, not how long it runs or when it finishes. Some documentation calls the second one an end time, so go by what the page shows.
04. Apply the weekend restriction
Check Respect Inventory Costing Time Restrictions on Weekends. NetSuite documents this box as keeping the costing process from running on weekends, so pending work waits for a permitted window. If your window starts on Friday evening, test how it treats Saturday morning before you rely on it.
05. Save and reopen the page
Click Save. In the example the page then lands on Setup Manager; the destination can vary by role and account. Open Setup > Accounting > Inventory Costing Preferences again. Schedule Inventory Costing reads Based on custom schedule, the two lists read 10:00 pm and 4:00 am, the weekend box is checked, and the two preferences below it are unchanged.
That reopened page is the check that the setting stuck. It says nothing yet about how costing behaves: watch a low-risk item's cost and the costing status available to your role over the first night, and check in the morning that costing finished.
Common questions
Does a custom schedule make inventory costing faster?
No. The schedule changes when a costing run may start. It does not change how long a run takes, and it does not guarantee that costing finishes by the latest time.
Do inventory transactions still save during the day?
Generally, yes. Inventory transactions can save while scheduled costing is deferred, subject to the account's normal inventory, period, approval and validation rules. Until the next permitted run, NetSuite uses an estimated cost that is documented as the applicable average cost for scheduled costing, so reports that read cost or inventory value can be provisional. The related accounting can be adjusted when the run completes. Standard-cost items keep standard costing rules.
Can the window cross midnight?
It can be set that way. In the example account the form accepted Earliest 10:00 pm and Latest 4:00 am. Treat it as an overnight start range, save, reopen to confirm the values, and verify the first run before you rely on it for period close or other commitments.
Which time zone do the two times use?
Check it in your account. The page does not say, and it is not established here whether the company time zone, the user's preference or something else applies. Record the time a test run starts and compare it with your settings.
What does the weekend box do?
It is documented as preventing the costing process from running on weekends. Do not assume it interrupts a run that already started. Test a Friday-evening start, a Saturday and Sunday start and the following Monday morning.
Why is After Transaction Entry missing from my list?
Available choices can vary by account and release. If After Transaction Entry is the current value, record it before you change it, because NetSuite may not offer it again after you move to another schedule.
Can I run costing outside the schedule?
Sometimes, through the period-close costing review. During Review Inventory Cost Accounting a Run Inventory Costing action may be available to override the schedule when the period-close conditions are met, such as no outstanding corrections and costing not already running or deferred. It is not a general manual scheduler. Confirm in your account how your role reaches it.
Will changing the schedule recost existing transactions right away?
Do not assume it will. The preference controls how scheduled costing starts going forward. Work that is already waiting, historical recalculations and backdated transactions follow their own processing. Review the costing status and the backlog after the change.
What are the other two preferences on the page?
Use Cost Estimate for Negative Inventory sets how NetSuite estimates cost when stock goes negative, and Use the Exact Cost for Linked Returns controls the cost a linked customer return uses. They are separate decisions and this setup does not change them.