Forecasting With Your Own Sales

Build the forecast at SKU level from your own completed orders, not from broad streetwear market claims, competitor launches or unsupported benchmarks. Start with a consistent sales window and separate delivered sales from cancellations and returns. For illustration only, if a hoodie sold 18, 22, 20 and 24 units in the last four weeks, its simple weekly average is 21 units. A recent-demand view could use the latest two weeks instead: (22 + 24) ÷ 2 = 23 units per week. Choose the method that reflects the change you can document, and record it.

Then adjust the unit forecast for known product-mix changes. If a collection sold 100 units with a 70% black and 30% grey split, but your recent completed orders show a 55% black and 45% grey split after a new color launch, forecast each variant from that observed mix rather than applying the old ratio. Check the result against product-level profitability, returns and current inventory. ORVX can show those measures, including remaining stock value and dead stock, while its inventory reorder calculator lets you test your own inputs. It reports your numbers; it does not decide or place the reorder.

Example of two demand views from one SKU's completed sales
MeasureCalculationWeekly forecast
Four-week average(18 + 22 + 20 + 24) ÷ 421 units
Recent two-week average(22 + 24) ÷ 223 units

Choosing Between Reorder Point and Days of Cover

A reorder point is a trigger: place a purchase order when projected available stock reaches the quantity needed to cover demand while the next shipment is on its way. It suits a SKU with a fairly stable replenishment process, because the decision is tied to an expected demand window rather than the calendar. Review the trigger when sales velocity or supplier timing changes.

Minimum-maximum levels add a target to that trigger. Set a minimum level that prompts action, then order enough to restore inventory to the maximum level. This works when you want each purchase to restore a defined operating range, especially across many SKUs with different order quantities or storage limits. Act when stock reaches the minimum, not only when it is already unavailable.

Days of cover converts inventory into time: available units divided by expected average daily unit sales. It is useful for comparing exposure across products and spotting a fast-moving style that may need attention before a fixed unit threshold would. Act when cover falls below your chosen threshold. These measures can be used together: use days of cover for monitoring, and a reorder point or minimum-maximum rule for the purchase decision. A reorder calculator can help structure the inputs.

Worked example with sample numbers

This example is illustrative. It uses sample numbers for a streetwear store selling in the US. They are made up to show the method, they are not a benchmark, and your own figures will differ.

Formula: Reorder point = daily units x (lead time + safety days).

Sample numbers: a reorder point
InputValue
Units sold per day8
Supplier lead time in days17
Safety cover in days7
Reorder at8 x (17 + 7) = 192 units
Cash tied up at cost$4797.02

Run the same sum with your own numbers in the free calculator, or browse guides for sellers in the US and more streetwear guides.

General information only: tax, duty and import rules change and depend on your situation, so check with an accountant or the official source before acting.

Eligible Shopify stores can see these numbers for their own store through the Founding 10,000 offer.

Lead Time and Safety Stock

Treat lead time as the full elapsed time from purchase order to sellable stock, not just the factory’s production estimate. Record supplier processing, production, freight, customs handling and local delivery separately, then add them. For illustration only, if observed demand is 20 units per week and the combined lead time is six weeks, lead-time demand is 20 × 6 = 120 units. Compare quoted and actual elapsed times: a supplier quoting four production weeks may still create a seven-week replenishment cycle after freight, customs and delivery.

Safety stock covers uncertainty around that 120-unit requirement. Do not add an arbitrary percentage. Use your own history to examine both demand variation and lead-time variation: if demand has ranged from 18 to 24 units weekly and shipments have taken five to seven weeks, exposure has ranged from 90 to 168 units. Set safety stock against the delay or demand range you are prepared to absorb, documenting the chosen risk boundary. Revisit it when suppliers, lanes or sales patterns change. The inventory reorder calculator can help test these inputs without treating a buffer rate as a universal rule.

How to Read the Worked Example

Read the worked calculation from left to right. The demand inputs establish the expected sales rate, while the lead-time inputs establish how long replenishment must cover. The calculation then converts those assumptions into demand during lead time, adds the selected safety-stock buffer, and produces the reorder point. The reorder point is the action trigger: compare it with projected available stock, not just the quantity currently on the shelf.

Treat each output as a different decision. Demand during lead time answers how much stock may sell before delivery; safety stock covers uncertainty in demand or elapsed time; the reorder point combines both into a replenishment threshold. Cash tied up is a separate view: apply the unit product cost to the inventory quantity being funded, making clear whether that quantity includes only on-hand stock or stock already ordered. If the result looks wrong, check the sales period, units, lead-time definition, cost currency and whether returns or cancellations were included. You can test those inputs in the inventory reorder calculator.

What Stock Costs to Hold

Stock costs more than the supplier invoice. For each SKU, record purchase cost, inbound charges, storage, insurance and financing. Add markdown exposure as an expected loss: if units may sell for $4 less than planned, that $4 belongs in the decision even though it is not paid upfront. Keep tax, duty and other legal charges as separate inputs unless you have a confirmed rate.

Use total cash cost to compare reorder economics, and use each component to choose the response. A high purchase or inbound cost calls for a smaller commitment or supplier review; rising storage or financing cost supports a faster sell-through decision; markdown exposure supports reducing the reorder or testing the price. The table shows the calculation at SKU level.

Example per-unit stock cost for one streetwear SKU
SKUPurchaseInboundStorage + insuranceMarkdown exposureFinancingTotal cash cost
Hoodie-001$18.00$3.00$1.00$4.00$0.60$26.60

Planning for Seasonal Peaks in the US

Map each planned peak on a US calendar: product launches, back-to-school, Labor Day, Thanksgiving through Cyber Monday, holiday gifting, and weather-sensitive periods. Add the date customers must be able to buy, then work backward through supplier processing, production, transit, customs, and receiving to set the purchase-order deadline. Mark supplier shutdowns and reduced-capacity periods on the same calendar; an order placed before a closure may still miss the required delivery window if production is not confirmed.

Treat the calendar as a timing plan, not proof that demand will last. A winter jacket launch may justify enough stock for the cold-weather window, while a limited graphic tied to a holiday may need a smaller event buy and a clear sell-through deadline. Separate a temporary peak uplift from the underlying run rate: protect availability for the event, then use completed sales and remaining stock to decide whether to reorder, hold, or reduce. A reorder calculator can help test the order date and quantity against different delivery windows.

Use each calendar input for a different planning decision
Calendar inputPlanning decision
Launch or holiday dateWhen sellable stock must be available
Weather-sensitive demandWhich styles need earlier availability
Supplier shutdownWhen production or dispatch may be unavailable
Event-only demandHow much to buy without treating the peak as permanent

A useful streetwear inventory plan connects your own sales forecast to the time each supplier and shipping route actually requires, then tests the resulting order against cash available and seasonal timing. Use the reorder point to identify when action is needed, safety stock to handle uncertainty, and holding-cost analysis to decide whether additional availability justifies the cash committed.

Sources

How this page was made: drafted with AI from a brief, then checked by automated rules for arithmetic, sources and duplication. The sample numbers were calculated, not reported.