Amazon FBA Restock Strategies: When and How Much to Send

The FBA Restocking Challenge

Running out of stock on Amazon is painful:

• Lost sales: Customers buy from competitors
• Ranking damage: Amazon deprioritizes out-of-stock listings
• Buy Box loss: Competitors win the Buy Box
• Momentum loss: Hard to recover velocity after stockouts

But sending too much to FBA has costs too:

• Storage fees: Monthly and long-term storage charges
• Tied-up capital: Money sitting in Amazon's warehouses
• Limit consumption: Using restock limits on slow-movers

The goal: maintain just enough FBA inventory to avoid stockouts while minimizing storage costs.

Understanding FBA Lead Time

Before calculating restock quantities, understand your FBA lead time:

Lead Time Components

Stage	Typical Duration
Warehouse picking/packing	1-2 days
Transit to Amazon	3-7 days
FBA check-in queue	1-7 days
FBA processing	1-3 days
Total	6-19 days

This varies by:

• Shipping method (small parcel vs. LTL/FTL)
• Time of year (longer during Q4)
• Amazon's capacity
• Your carrier's speed

Track your actual FBA lead time by monitoring shipments in Seller Central.

FBA Reorder Point Formula

FBA Reorder Point = (Daily Sales × FBA Lead Time) + Safety Stock

Example:

Daily Sales: 15 units
FBA Lead Time: 14 days
Safety Stock: 7 days (105 units)

Reorder Point = (15 × 14) + 105 = 315 units

When FBA inventory hits 315 units, create your next shipment.

How Much to Send

Once you hit the reorder point, how much do you send?

Option 1: Economic Order Quantity

Balance shipping costs vs. storage costs:

• Fewer, larger shipments: Lower shipping cost per unit, higher storage
• More, smaller shipments: Higher shipping cost per unit, lower storage

For most sellers, 2-4 weeks of inventory per shipment is optimal.

Option 2: Target Inventory Level

Set a target FBA inventory level and ship the difference:

Ship Quantity = Target Level - Current FBA - In-Transit

Example:

Target: 600 units (6 weeks supply)
Current FBA: 200 units
In-Transit: 100 units
Ship Quantity: 600 - 200 - 100 = 300 units

Option 3: Fixed Shipment Cadence

Ship a consistent quantity on a regular schedule:

• Weekly shipments of 100 units
• Bi-weekly shipments of 200 units
• Monthly shipments of 500 units

Simple to manage but less responsive to demand changes.

Restock Limit Strategies

Amazon limits FBA inventory. Here's how to work within them:

Improve Your IPI Score

Higher IPI = Higher limits. Focus on:

• Sell-through rate: Move slow inventory
• Excess inventory: Reduce overstocked items
• Stranded inventory: Fix listing issues
• In-stock rate: Keep popular items available

Prioritize High-Velocity Items

When limits are tight:

1. Rank products by sales velocity
2. Allocate FBA space to top sellers
3. Use FBM (merchant fulfilled) for slower movers

Time Shipments Strategically

• Check limits before creating shipments
• Send shipments right after limit resets (if applicable)
• Don't let shipments expire without delivery

Use Amazon Warehousing Distribution (AWD)

For sellers with consistent high volume, AWD provides:

• Upstream storage at lower cost
• Automatic replenishment to FBA
• Better limit management

Seasonal Restocking

Peak seasons require advance planning:

Pre-Q4 Buildup

Start building FBA inventory in September:

• October: Stock up to 6-8 weeks
• November: Peak inventory levels
• December: Maintain and monitor

Post-Season Drawdown

Reduce inventory after peak:

• January: Let inventory normalize
• February: Clear any excess
• Watch for long-term storage fees

Off-Season Management

During slow periods:

• Lower safety stock levels
• Extend time between shipments
• Consider removing slow-movers

Multi-Channel Restocking

If you sell on both Shopify and Amazon:

Coordinate Inventory Allocation

Your warehouse stock serves two purposes:

1. Shopify fulfillment
2. FBA replenishment

Ensure you're not over-allocating to one channel.

Unified Forecasting

Forecast total demand across channels:

Total Demand = Shopify Demand + Amazon Demand
Warehouse Needs = Shopify Demand + FBA Replenishment

Priority Rules

When inventory is limited:

• Which channel gets priority?
• What's the minimum for each channel?
• When do you split vs. allocate fully?

Restock Automation

Manual restocking works but doesn't scale:

Manual Process

1. Check FBA inventory daily
2. Compare to reorder points
3. Calculate shipment quantities
4. Create shipping plans
5. Ship to Amazon

Problems: Time-consuming, easy to miss, no proactive alerts.

Automated with ReplenishRadar

ReplenishRadar provides FBA transfer suggestions:

• Monitors FBA inventory continuously
• Alerts when restock is needed
• Recommends shipment quantities
• Tracks in-transit inventory
• Adjusts for seasonality

Get alerts like: "Send 450 units to FBA by Friday to avoid stockout."

Common FBA Restock Mistakes

Mistake 1: Waiting Too Long

Don't wait until you're almost out. FBA processing takes time.

Fix: Set reorder points with adequate lead time buffer.

Mistake 2: Ignoring FBA Processing Time

Inventory in transit isn't sellable. Factor in FBA check-in time.

Fix: Track actual FBA processing times and adjust calculations.

Mistake 3: Overstocking Slow Movers

Sending too much of slow products wastes limits and incurs fees.

Fix: Match restock quantity to actual velocity.

Mistake 4: Not Tracking In-Transit

You might reorder when inventory is already on its way.

Fix: Track all in-transit shipments in your calculations.

Mistake 5: Reactive Instead of Proactive

Restocking when you notice low stock is already too late.

Fix: Use automated monitoring and alerts.

FBA Restock Checklist

Before each FBA shipment:

• Check current FBA inventory levels
• Review in-transit shipments
• Verify restock limits available
• Calculate days of supply at current velocity
• Confirm warehouse has stock to send
• Consider seasonality adjustments
• Create shipping plan in Seller Central
• Schedule carrier pickup

Key Metrics to Track

Days of Supply at FBA

FBA Days of Supply = Current FBA Inventory / Daily Sales

Target: 3-6 weeks depending on lead time.

Stockout Frequency

How often do you run out at FBA?

Target: Less than 2% of days.

FBA Inventory Turnover

FBA Turnover = (Sales per Month × 12) / Average FBA Inventory

Higher is better (faster selling, less capital tied up).

Perfect Shipment Rate

What percentage of shipments arrive on time and intact?

Target: Above 95%.

Summary

Successful FBA restocking requires:

1. Know your lead time: Including FBA processing
2. Set proper reorder points: Sales velocity × lead time + safety stock
3. Ship the right quantity: Balance storage costs vs. stockout risk
4. Work within limits: Prioritize high-velocity products
5. Automate monitoring: Don't rely on manual checks

Master these fundamentals and you'll minimize stockouts while optimizing FBA costs.

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ReplenishRadar monitors your FBA levels and alerts you when it's time to send more inventory. We calculate optimal transfer quantities based on your sales velocity and lead times.

• Know exactly when to ship to FBA
• See transfer suggestions by priority
• Track shipments until received
• Catch discrepancies automatically

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Related Reading:

• Fix FBA Stranded Inventory
• Amazon FBA Tools
• Stockout Cost Calculator