Black Friday Inventory Planning: How to Stock for BFCM Without Running Out (or Overbuying)

Inventory is the invisible killer of Black Friday success. Run out of your bestseller on Friday afternoon, and you've left thousands on the table while your ads keep running for products you can't sell. Overbuy, and you're discounting already-discounted inventory through January just to clear it.

The merchants who nail BFCM inventory planning use data, not gut instinct. Here's how they do it.

The Two Ways Inventory Goes Wrong

Scenario 1: The Stockout Disaster

A clothing brand runs a 30% off BFCM sale. Their top-selling sweater, which does 20% of their revenue, sells out Friday at 2 PM. Traffic keeps coming, ads keep running, and customers keep landing on a product page that says "Sold Out."

What it costs:

• Lost sales (obviously)
• Wasted ad spend driving traffic to sold-out products
• Frustrated customers who may not come back
• Damage to BFCM momentum (one stockout leads to customers leaving entirely)

Scenario 2: The Inventory Hangover

A skincare brand gets excited about BFCM potential. They order 3x their normal inventory, anticipating massive demand. Demand is solid, up 50% from last year, but nowhere near 3x. Now they're sitting on six months of inventory that's already been associated with deep discounts.

What it costs:

• Cash tied up in inventory
• Storage costs
• Eventual deeper discounting just to move product
• Margin erosion on future sales

Both scenarios are preventable with proper planning.

Step 1: Know What You're Planning For

Before forecasting units, understand your BFCM strategy:

What's the promotional structure?

• Sitewide discount: Plan for lift across all products
• Product-specific discounts: Focus forecasting on promoted items
• Bundles: Plan component inventory for bundle configurations
• Tiered discounts: Higher AOV might mean fewer units at higher value

What marketing investment are you making?

• 50% more ad spend = expect roughly 30-50% more traffic
• New channels (TikTok, influencers) = harder to predict
• Email-only promotion = more predictable based on list performance

What's your risk tolerance?

• Conservative: Willing to sell out early rather than overbuy
• Aggressive: Willing to carry extra inventory to capture every sale
• Most stores should lean conservative, especially in uncertain economic conditions

Step 2: Gather Your Data

Good forecasting requires data. Here's what to collect:

If You Have BFCM History

• Unit sales by SKU during BFCM last year
• Daily sales patterns (Friday vs. Saturday vs. Sunday vs. Monday)
• Conversion rate during BFCM vs. normal periods
• Traffic by source during BFCM
• Stock-out timing (when did things run out last year?)
• Return rate for BFCM orders

If You're New to BFCM

• Current average weekly sales by SKU
• Year-to-date growth rate (are you trending up or down?)
• Industry BFCM lift estimates (typically 3-10x normal weekend, depending on category)
• Competitor activity (how aggressive is your space during BFCM?)

Universal Data Needs

• Current inventory levels by SKU
• Supplier lead times (can you reorder if needed?)
• Storage constraints (how much can you physically hold?)
• Cash flow limits (how much inventory can you afford to buy?)

Step 3: The Forecasting Process

Method 1: Historical Multiplier (For Stores With BFCM History)

Formula: Forecast = Last Year BFCM Units × (1 + YTD Growth) × Marketing Multiplier × Safety Buffer

Example:

• Sold 200 units of Product A during BFCM 2024
• Year-to-date sales are up 15%
• Spending 25% more on marketing this year
• Want 20% safety buffer

200 × 1.15 × 1.25 × 1.20 = 345 units

Round to 350 units.

Method 2: Lift Estimation (For New Stores)

Formula: Forecast = Normal Weekend Units × BFCM Lift Factor × Safety Buffer

Typical lift factors by category:

• Fashion/apparel: 4-6x
• Beauty/skincare: 3-5x
• Electronics: 6-10x
• Home goods: 3-5x
• Food/beverage: 2-4x

Example:

• Normal weekend: 50 units
• Category suggests 5x lift
• Conservative safety buffer: 10%

50 × 5 × 1.10 = 275 units

Method 3: Top-Down Revenue (Sanity Check)

Use your revenue target to validate unit forecasts.

Formula: Expected Units = Revenue Target ÷ Average Selling Price (after discount)

Example:

• Revenue target: $50,000
• Product ASP normally: $60
• BFCM discount: 25%
• BFCM ASP: $45

$50,000 ÷ $45 = 1,111 total units needed

Compare this to your bottom-up SKU forecasts. If there's a big gap, investigate.

Step 4: SKU-Level Planning

Don't just plan total inventory, plan at the SKU level.

Category A: Bestsellers (Top 10-20% of SKUs)

These drive most of your revenue. Stock aggressively.

• Forecast: Use historical method with 20-30% safety buffer
• Goal: Don't run out until late Sunday at earliest
• Action: Order early, confirm delivery, have backup supplier if possible

Category B: Average Performers (Middle 50-60%)

Solid products that contribute but aren't stars.

• Forecast: Historical method with 10-15% safety buffer
• Goal: Have enough but don't overbuy
• Action: Standard order timing, monitor during BFCM

Category C: Slow Movers (Bottom 20-30%)

Products that don't move fast normally.

• Forecast: Current inventory only, or minimal additional
• Goal: Use BFCM to clear this inventory
• Action: Consider deeper discounts to move these

Size/Color Considerations

Critical: A product isn't "in stock" if the popular sizes are sold out.

Analyze historical size curves:

• What % of sales are each size?
• Which sizes/colors sell out first?
• Order to match the demand curve, not evenly across variants

Step 5: The Safety Stock Decision

How much buffer inventory to carry is a judgment call. Here's a framework:

Arguments for More Safety Stock

• Product has high margin (can afford to carry extra)
• Supplier lead times are long (can't reorder quickly)
• Product is a bestseller (stockout is very costly)
• You're investing heavily in marketing (expecting high traffic)
• Past BFCM showed stockouts cost you sales

Arguments for Less Safety Stock

• Product has low margin (carrying cost hurts)
• Product is seasonal/trendy (won't want it in January)
• Supplier is reliable for quick reorders
• You're being conservative with marketing
• Storage space is limited

Safety Stock by Product Type

| Product Category | Suggested Safety Buffer | |-----------------|------------------------| | Bestsellers | 25-30% | | Core products | 15-20% | | Average performers | 10-15% | | Slow movers | 0% (use existing) | | New products | 20% (more uncertainty) |

Step 6: The Cash Flow Reality

Inventory costs money. Make sure your plan is financially viable.

Calculate Total Inventory Investment

Total Cost = Σ (Unit Forecast × Unit COGS) for all SKUs

Example:

• Product A: 350 units × $20 = $7,000
• Product B: 200 units × $30 = $6,000
• Product C: 150 units × $15 = $2,250
• Total inventory investment: $15,250

Check Against Available Capital

• How much cash do you have for inventory?
• What's your supplier payment terms?
• Can you negotiate extended terms for BFCM orders?
• Do you have inventory financing options?

Prioritization If Cash-Constrained

If you can't afford your full forecast:

1. Fund bestsellers fully (highest ROI)
2. Fund core products at 80% of forecast
3. Skip additional ordering for slow movers entirely
4. Consider pre-orders for high-demand items

Step 7: Supplier and Logistics

Order Timing

Work backwards from BFCM:

• BFCM weekend: November 28-December 1 (example)
• Inventory must be received: November 20 (week buffer)
• Shipping time: 2-4 weeks (depending on supplier)
• Order must be placed: Late October / early November

Rule of thumb: Place orders 6-8 weeks before BFCM for domestic suppliers, 10-12 weeks for international.

Supplier Communication

Tell your suppliers what's coming:

• Share your forecast (helps them prepare)
• Confirm lead times (in writing)
• Establish reorder protocol (can you get emergency shipments?)
• Confirm they're not running promotions that will affect their capacity

Backup Plans

Scenario: Supplier delays, shipment stuck in customs, quality issues.

• Identify backup suppliers for critical products
• Know which products you can substitute
• Understand dropship options for emergency fulfillment
• Have a communication plan for customers if inventory doesn't arrive

Step 8: During BFCM, Real-Time Inventory Management

Monitoring

Set up alerts for:

• Products hitting 50% of BFCM allocation
• Products hitting 20% remaining
• Any product at <10 units
• Products selling 2x faster than forecast

Response Playbook

Selling faster than expected:

• Reduce ad spend on that product (if you'll sell out anyway)
• Add "low stock" messaging to create urgency
• Consider pulling from other channels (marketplaces) to save for your site

Selling slower than expected:

• Increase ad spend if margin allows
• Add flash discounts
• Feature in email sends
• Create urgency ("Today only" additional discount)

Product sells out:

• Stop ads immediately
• Add waitlist functionality
• Suggest alternatives
• Communicate restock timeline if known

Common Inventory Planning Mistakes

Mistake 1: Planning at Category Level, Not SKU Level

"We need 500 t-shirts" is not a plan. "We need 50 small, 100 medium, 150 large, 100 XL, 50 2XL in each of 3 colors" is a plan.

Mistake 2: Ignoring Variant Distribution

If 40% of your sales are Medium and you ordered equal quantities across sizes, you'll have stockouts in Medium while sitting on XS and 2XL.

Mistake 3: Ordering Based on Gut

"I feel like this will be big" is not forecasting. Use data, even imperfect data.

Mistake 4: Not Accounting for Returns

BFCM returns run 20-30% higher than normal. If you're calculating break-even, factor in that some of those sales will come back.

Mistake 5: Forgetting Supplier Constraints

Your supplier might not be able to deliver what you want on your timeline. Confirm capacity before finalizing forecasts.

Mistake 6: Planning Inventory, Not Cash Flow

You might need 500 units, but can you afford 500 units? Match your plan to your capital.

Post-BFCM: Dealing with What's Left

If You Understocked (Sold Out Early)

• Document what sold out and when
• Calculate estimated lost revenue
• Consider longer sale period next year
• Explore faster fulfillment options

If You Overstocked (Inventory Remaining)

Tiers of action:

1. Cyber Week extension: Continue deals through the week
2. December promotions: Holiday shopping continues
3. January clearance: "New year, fresh start" sale
4. Bundle with new products: Pair old inventory with new arrivals
5. Donate for tax benefit: If nothing else works

Don't let BFCM inventory become February inventory. The longer you hold it, the worse the economics get.