Peak season is when inventory mistakes cost the most. A stock-out on your best seller loses the sale and the customer, and too much of the wrong stock ties up cash right when you need it. In Linnworks’ analysis of 207 million orders, nearly a third of the year’s orders landed in Q4, so the weeks before it are where inventory work pays off.

This checklist covers 11 steps, from reviewing last peak’s data to the post-peak clearance, with a short checklist for each. For the wider season, see our peak season ecommerce guide, and for planning detail, our guide to peak season inventory planning. You can also get our peak season red flags checklist.

Step 1: Review data from previous peaks

Start with what actually happened last time: sales by product and channel, sell-through, stock-outs, overstock, returns, and how long it took to fulfill orders.

Look for patterns

Which products sold out, and when? Which ones were left over? Where did orders pile up? These answers shape this year’s plan more than any general benchmark.

Set measurable goals

Turn the review into targets for inventory, such as fewer stock-outs, lower overstock, or better order accuracy, so you can tell afterward whether the plan worked.

Step 1 checklist

• Pulled last peak’s sales, stock-out, overstock, and returns data by channel
• Listed the products and decisions that worked, and the ones that didn’t
• Set measurable inventory goals for this peak

Step 2: Forecast demand

A forecast turns your history into a plan for what to buy and where to hold it. Combine last peak’s sales with current trends, your promotions calendar, and any new products or channels. See our guide to forecasting before peak, and Linnworks’ stock forecasting to predict demand proactively.

Plan for the unexpected

Build in a buffer for demand spikes and supply delays. Decide in advance what you’ll do if a product takes off, or if a shipment arrives late.

Step 2 checklist

• Built a forecast by product and channel from last peak, trends, and your promotions plan
• Included a buffer for spikes and delays
• Agreed what to do if a product sells much faster or slower than forecast

Step 3: Audit your stock and your data

You can’t plan with numbers you don’t trust. In the State of Commerce Ops 2026 report, only about a third of retailers (33.2% in the UK and 37.2% in the US) reported excellent inventory visibility across channels and warehouses.

Run cycle counts

Check physical stock against your system, starting with best sellers and high-value items, and fix mismatches before peak. See our inventory audit guide.

Clean up your product data

Check SKUs, barcodes, bundles, and locations, so pickers and your channels are working from the same information.

Step 3 checklist

• Counted best sellers and high-value items and corrected discrepancies
• Checked SKUs, barcodes, bundles, and bin locations
• Confirmed system stock matches what’s on the shelf

Step 4: Segment your inventory and arrange the warehouse

Group your stock by how fast it moves. Fast movers should sit where they’re quickest to pick and pack, and slow movers can go further from the packing area. If that means reorganizing, it’s usually worth it before peak.

Protect your best sellers

Make sure you have enough of the products that drive the most sales, and reorder early so you don’t disappoint customers.

Step 4 checklist

• Identified fast-moving and slow-moving stock
• Placed fast movers where they’re quickest to pick
• Checked best sellers have enough stock for the forecast

See our guides to efficient order picking and warehouse KPIs for peak season.

Step 5: Set safety stock and reorder points

Safety stock is the buffer that protects you from demand spikes and late deliveries, and a reorder point tells you when to order. Peak raises both, so reset them for the season instead of relying on your normal levels.

Automate where you can

Set automatic reorder alerts so low stock or a sudden spike prompts action without anyone checking spreadsheets by hand.

Step 5 checklist

• Reset safety stock for peak demand and current lead times
• Calculated reorder points for your key products
• Set up alerts for low stock and demand spikes

See our guide to the safety stock formula.

Step 6: Plan with your suppliers

Reliable supply is what makes the forecast possible. Talk to suppliers early about your volumes, their capacity, and their lead times.

Share your forecast

Giving suppliers your expected volumes lets them plan, and makes shortages less likely.

Line up backups and terms

Identify backup suppliers before you need them, and agree terms for peak, including delivery times, payment terms, and what happens to leftover stock.

Step 6 checklist

• Shared your peak forecast and timeline with suppliers
• Confirmed their capacity and lead times
• Identified backup suppliers
• Agreed peak terms, including returns of leftover stock

Step 7: Allocate stock across channels

Every channel peaks at the same time, so decide how much stock each one gets, based on how it performed in the past, along with its margins and delivery options. Marketplaces with their own inbound deadlines, such as fulfillment programs, need stock sent early. Review each channel’s requirements well before peak. See our guides to multichannel inventory management and the common problems and how to fix them.

Keep every channel in sync

A sale on one channel needs to update availability everywhere. Linnworks syncs stock across 100+ native channel integrations in under 10 minutes.

Test new channels early

If you’re adding a channel, set it up and test it before peak so you’re not learning it in November.

Step 7 checklist

• Set an allocation by channel using past performance and margins
• Checked each channel’s inbound deadlines and requirements
• Confirmed stock syncs across every channel
• Set up and tested any new channel before peak

Step 8: Check storage and overflow capacity

Peak stock needs space. Check whether your warehouse can hold the extra inventory, and plan overflow in advance, such as temporary space or a third-party logistics (3PL) partner, instead of finding out when the pallets arrive.

Step 8 checklist

• Estimated the extra space peak stock needs
• Arranged overflow storage or fulfillment if needed
• Checked that inbound deliveries are scheduled to fit your capacity

See our guide to 3PL warehouse logistics.

Step 9: Prepare for returns and restocking

Returns rise after the holidays, and returned stock only helps if it gets back into availability quickly. Plan the process, space, and staff for it, and decide how you’ll grade, repackage, and restock items.

Step 9 checklist

• Reviewed return policies and gift return windows
• Planned space and staff for incoming returns
• Set up a process to inspect and restock returned items quickly

See our guide to returns management.

Step 10: Monitor your inventory daily during peak

Once peak starts, check a short list of measures every day: stock cover on best sellers, stock-outs, oversells, inbound delivery status, and orders waiting to be picked. Catching a problem on day one is far cheaper than catching it on day five.

Step 10 checklist

• Chose a short list of daily inventory measures
• Assigned someone to review them each day
• Agreed what triggers an urgent reorder or a change of allocation

Step 11: Review and clear stock after peak

When the rush ends, review how the plan performed against the goals you set in step 1. Look at what sold out, what’s left over, and where your forecast was wrong, and write it down while it’s fresh.

Clear leftover stock

Decide what to discount, bundle, or move to other channels, before storage costs and ageing stock eat into your margin. See our inventory reduction strategies.

Step 11 checklist

• Reviewed results against your goals
• Recorded what sold out, what was left over, and why
• Made a plan to clear leftover stock
• Saved your notes for next year’s forecast

Peak season inventory checklist: summary

• 1. Review last peak’s data and set measurable goals.
• 2. Forecast demand by product and channel.
• 3. Audit your stock and data so you can trust the numbers.
• 4. Segment inventory and arrange the warehouse around fast movers.
• 5. Set safety stock and reorder points for peak.
• 6. Plan with suppliers, including backups and terms.
• 7. Allocate stock across channels and keep them in sync.
• 8. Check storage and overflow capacity.
• 9. Prepare for returns and quick restocking.
• 10. Monitor daily during peak.
• 11. Review and clear stock after peak.

For the full season, including staffing and customer service, see our peak season ecommerce guide and our guides to seasonal hire vs. overtime and peak season shipping. For a printable version, get our peak season red flags checklist.

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