WSSI stands for Weekly Sales, Stock & Intake. It is a retail planning view that tracks how sales, stock, intake, and inventory cover move week by week, so a planner can see whether stock is building up or running thin against the rate of sale. Its core identity is closing stock = opening stock + intake − sales.

How is WSSI different from OTB?

Open-to-buy (OTB) answers how much you can still commit to buy within a financial plan over a period. WSSI answers how sales, stock, and intake actually flow week to week, and how many weeks of cover the remaining stock represents. OTB sizes the budget; WSSI phases and monitors it. UK and European planning teams tend to rely heavily on WSSI as their primary trading view.

What does a WSSI show you?

A WSSI shows opening stock, planned and actual sales, planned and actual intake, and closing stock for each week, alongside weeks of cover. Read together, those lines tell you whether intake is arriving in time to support sales, where cover is too high or too low, and when a line is heading for a stock-out or an overstock that will need markdown.

Can I run WSSI in Excel, and why does it get hard?

Yes — for a single department a spreadsheet WSSI works fine. It gets hard at scale: multiple teams editing copies creates version-control problems, intake dates change and have to be updated by hand each week, and reconciling WSSI against the OTB budget across many lines and channels becomes error-prone. The weekly maintenance, not the maths, is what breaks down.

// Tools

WSSI calculator

WSSI — Weekly Sales, Stock & Intake — is the retail planning view that tracks stock flow week by week. Its core identity is closing stock = opening stock + intake − sales, with weeks of cover showing how long the remaining stock lasts.

Enter a period below to project closing stock and weeks of cover.

Opening stock (BOP, units)

Intake / receipts (units)

Sales over the period (units)

Weeks in the period

Enter opening stock, intake, and sales to project closing stock and weeks of cover.

// How it works

01
Enter opening stock (BOP)
The stock you hold at the start of the period.
02
Enter intake and sales
Planned receipts into the period and planned sales over it.
03
Enter weeks in the period
Used to convert period sales into an average weekly rate.
04
Read closing stock + cover
Closing = opening + intake − sales. Weeks of cover = closing ÷ average weekly sales.

// Related

This WSSI calculator projects the weekly stock flow. To understand the method end to end, read what a WSSI is. The intake line ties straight to your buying budget — size it with the open-to-buy calculator, and see how the two views fit together in OTB vs. WSSI.

Running WSSI in Excel? See how RetailNorthstar keeps WSSI, OTB, intake, and buy plans connected.

// Next step

Your calculator result is one number. RetailNorthstar keeps the whole plan connected — line plan, OTB, assortment, buy, POs, and production.

See the connected workflow →

// Running WSSI in Excel?

WSSI and OTB answer different questions. Open-to-buy sizes how much budget is left to commit over a period; WSSI phases that buy and tracks how sales, stock, and intake flow week by week, with weeks of cover showing how long the remaining stock lasts. Most teams need both — the WSSI is where the OTB plan gets monitored as the season actually trades.

A spreadsheet WSSI holds up for one department, but breaks at scale: copies drift out of version control, intake dates change and have to be re-keyed every week, and reconciling cover against the OTB budget across many lines and channels turns into manual cleanup. RetailNorthstar keeps sales, stock, intake, and OTB on one record, so the weekly position stays live where buying decisions are made.

// FAQ

Frequently asked questions

What is WSSI?: WSSI stands for Weekly Sales, Stock & Intake. It is a retail planning view that tracks how sales, stock, intake, and inventory cover move week by week, so a planner can see whether stock is building up or running thin against the rate of sale. Its core identity is closing stock = opening stock + intake − sales.
How is WSSI different from OTB?: Open-to-buy (OTB) answers how much you can still commit to buy within a financial plan over a period. WSSI answers how sales, stock, and intake actually flow week to week, and how many weeks of cover the remaining stock represents. OTB sizes the budget; WSSI phases and monitors it. UK and European planning teams tend to rely heavily on WSSI as their primary trading view.
What does a WSSI show you?: A WSSI shows opening stock, planned and actual sales, planned and actual intake, and closing stock for each week, alongside weeks of cover. Read together, those lines tell you whether intake is arriving in time to support sales, where cover is too high or too low, and when a line is heading for a stock-out or an overstock that will need markdown.
Can I run WSSI in Excel, and why does it get hard?: Yes — for a single department a spreadsheet WSSI works fine. It gets hard at scale: multiple teams editing copies creates version-control problems, intake dates change and have to be updated by hand each week, and reconciling WSSI against the OTB budget across many lines and channels becomes error-prone. The weekly maintenance, not the maths, is what breaks down.

// Related resources

See the connected workflow in RetailNorthstar →

A real WSSI runs every week across many lines and channels. New to it? Read what a WSSI is and how to build one, download the free WSSI template, or pair it with the open-to-buy calculator.

Book a Demo →See RetailNorthstar →