Safety Stock and Reorder Point Calculator for Peak Season

Key facts

• Latest safe order date = peak start minus lead time minus safety stock minus inbound processing time.
• For a 45-day overseas lead time and two weeks of safety stock, orders for a November peak should be placed by mid-September.
• Amazon and Walmart storage fees roughly triple from October through December.
• The deepest discount that still grows profit depends on margin and the lift the promo produces; the planner names it.

Last updated September 7, 2026. Fee presets, payout timing, and Onramp Funds eligibility and fee example checked against the published sources listed at the end of this page.

How to use the peak season planner

Enter your current daily sales, the peak-season multiplier you expect, units on hand, supplier lead time, and the safety stock you want. The planner returns the latest safe order date, the units to order to cover peak, the purchase order total with deposit and balance timing, the contribution the peak run produces, and the deepest discount that still grows profit at your margin. The cash timeline shows the deposit, the balance at shipment, and peak sell-through paying back.

• Peak-season multiplier: peak month sales divided by a normal month. 2x to 3x is typical for Q4 in gifting categories; Prime Day and back-to-school peaks are shorter and sharper.
• Safety stock: days of buffer against a late shipment. Two weeks is a common floor for overseas suppliers in Q4.
• Sales lift from a promo: the extra units a discount produces. The planner uses it to find the discount depth that keeps profit flat, which is the deepest you should go for growth rather than clearance.

What makes this different

• Reorder date, quantity, and cash together: most reorder calculators stop at a reorder point. This one shows the deposit and balance on a timeline against the contribution the peak produces, which is the number that decides whether you can self-fund it.
• Discount guardrail: a promo that grows revenue and shrinks profit is the most common Q4 mistake. The planner names the depth where that starts.
• Cash timeline on every result: when the money goes out, when it comes back, and the lowest point in between.
• Compare two scenarios side by side, share a link with your numbers, or save the result as a PDF. Inputs carry over between the calculators on this site.
• Nothing is stored. Everything runs in your browser.

The three Q4 numbers to get right

Order date, order size, and discount depth. Order too late and the peak arrives before the stock does. Order too much and Q4 storage fees, which roughly triple on Amazon and Walmart from October through December, eat the margin. Discount too deep and the lift never pays for itself. Every one of those decisions has to be made before the payouts from peak sales arrive, which is why sellers fund the peak order against future sales. Onramp Funds advances capital against combined sales across 9 platforms, repaid as a percentage of peak sales as they land. No personal credit check. See how much capital your combined revenue unlocks.

Sources

• Amazon selling fees and FBA rate card
• Walmart Marketplace referral and WFS fees
• Onramp Funds: how it works, eligibility, and fee example

Frequently asked questions

When should I place my Q4 inventory order?

Count back from the start of your peak: lead time plus safety stock plus inbound processing time. For a 45-day overseas lead time and two weeks of safety stock, orders for a November peak should be placed by mid-September.

How much should I discount for Black Friday?

Enter your margin and expected lift; the planner shows the depth where profit stays flat. Below that, a discount grows profit; deeper, it only grows revenue.

Does this planner store my data?

No. Everything runs in your browser and nothing is uploaded.