> ## Documentation Index > Fetch the complete documentation index at: https://docs.vortexiq.ai/llms.txt > Use this file to discover all available pages before exploring further. # Stock vs Sales Velocity, Shopify > Days-of-cover per SKU = on-hand / 30D velocity. Surfaces stockout risk before it bites. How to read it, why it matters, and how to act on it. **Metrics type:** [Supporting Metrics](/nerve-centre/overview#metrics-types-explained) • **Category:** [Ecommerce Platform](/nerve-centre/connectors#connectors-by-type) > Days-of-cover per SKU = on-hand / 30D velocity. Surfaces stockout risk before it bites. ## At a glance > Per-SKU days-of-cover, computed as `Available ÷ avg_units_sold_per_day_30D`. The forecasting view of inventory: which variants will OOS in 5 days, 14 days, 30 days, given current velocity? | | | | ----------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **What it counts** | For each active variant: `totalInventory ÷ (units_sold_30D ÷ 30)`. Variants with zero sales in 30D are excluded (no velocity = undefined cover). The card surfaces a sortable list bucketed by cover-band. | | **VAT / tax treatment** | Not applicable, count metric. | | **Shipping** | Not applicable. | | **Discounts** | Not applicable. | | **Refunds** | Sales numerator includes refunded units (the velocity reflects gross demand, not net). For net-velocity, subtract refunded units; on the roadmap. | | **Cancelled / voided orders** | Excluded from velocity if Shopify removed them. Included if still in index. | | **Currency** | Not applicable. | | **Channels / sources** | All channels contribute to velocity. POS draws same as online. | | **Time window** | `30D` velocity window; cover figure is real-time given current stock | | **Alert trigger** | None directly; pair with workspace thresholds (e.g. "alert if any SKU in top-50 has \<14 days cover"). | | **Roles** | owner, operations | ## Calculation Calculated automatically from your Shopify data. See the At a glance summary above for what the metric tracks and the worked example below for a typical reading. ## Worked example A US apparel DTC brand on Shopify, \~1,800 active variants. 30D window 12 Apr 26 to 12 May 26. Top-by-velocity variants: | Variant | On-hand | 30D units sold | Days cover | Bucket | | --------------------------- | ------- | -------------- | ---------- | -------------------- | | Linen tee, Sand, M | 8 | 240 | 1.0 | **Critical (≤7d)** | | Linen tee, Sand, L | 32 | 220 | 4.4 | **Critical (≤7d)** | | Wide-leg trouser, Black, 10 | 56 | 180 | 9.3 | At risk (8-14d) | | Linen tee, White, M | 102 | 195 | 15.7 | Comfortable (15-30d) | | Bucket hat, Olive, OS | 18 | 35 | 15.4 | Comfortable (15-30d) | | Wide-leg trouser, Cream, 12 | 240 | 90 | 80.0 | Surplus (>60d) | | Linen tee, Black, S | 480 | 30 | 480 | Surplus, slow-mover | Six things to notice: 1. **Sand M is the urgent fire.** 1.0 day cover; OOS imminent. PO arrival or stock transfer needed today. Cross-reference [Inventory Alerts](/nerve-centre/kpi-cards/shopify/products-with-zero-negative-stock) for the live OOS list including this SKU within hours. 2. **Sand L is on borrowed time.** 4.4 days cover at current velocity. Standard reorder lead time is typically 14-21 days; this SKU will OOS before reorder arrives unless emergency stock transfer is arranged. 3. **The "at risk" bucket is the planning-priority list.** 9.3 days cover means OOS in \~10 days; with normal lead times, the action window closes today. This is where ops attention should focus. 4. **Surplus on Cream 12 is signal.** 80 days cover at 90 units/30D means demand is asymmetric across colour-size combinations. Cream 12 is a slow-mover; allocate fewer units in next PO cycle. 5. **Linen tee Black S has 480 days cover.** Either over-ordered (capital tied up) or genuinely a slow-mover that should be marked-down or de-listed. Pair with margin-per-unit to decide clearance vs hold. 6. **Velocity assumes recent demand continues.** Marketing pushes, viral moments, or seasonal peaks invalidate the assumption. Sand M's 240 units/30D could collapse to 80 next month if the marketing wave passes; cover would extend to \~3 days from a single day. Pair with marketing calendar to forecast better. ## Sibling cards merchants should reference together Stock vs Sales velocity is the forecasting cousin. Companions: | Card | Why pair it with Stock vs Sales | | ------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------ | | [Products with Zero/Negative Stock](/nerve-centre/kpi-cards/shopify/products-with-zero-negative-stock) | The OOS list. This card predicts which non-OOS variants will fall onto that list next. | | [Inventory Distribution](/nerve-centre/kpi-cards/shopify/inventory-distribution) | The aggregate band view; this card is the per-SKU detail. | | [OOS Spike Alert](/nerve-centre/kpi-cards/shopify/oos-spike-alert) | The acute-event alert. Stock-vs-sales is the steady forecasting view. | | [Top SKUs](/nerve-centre/kpi-cards/shopify/top-skus) | Velocity drill-down by SKU; primary input to this card. | | [Top Products by Revenue](/nerve-centre/kpi-cards/shopify/top-products-by-revenue) | The £-weighted velocity. A high-velocity SKU might not be top-revenue if it's a low-margin item. | | [Bottom Products](/nerve-centre/kpi-cards/shopify/slow-moving-products) | The slow-mover list; surplus-cover variants. | | [Fulfillment Rate](/nerve-centre/kpi-cards/shopify/fulfillment-rate) | Persistent low-cover on top SKUs eventually drags fulfilment rate. | ## Reconciling against the vendor's own dashboard **Where to look in Shopify Admin:** Shopify doesn't expose days-of-cover natively. Closest reconstructions: * **Reports → Inventory → Sell-through rate**: shows what % of stock sold in a period; mathematically related but not days-of-cover. * **Apps like Stocky / Inventory Planner / Cogsy**: typically expose days-of-cover and reorder forecasting. * **Reports → ABC analysis** (Shopify Plus): SKU-velocity classification (A = top, B = middle, C = slow). **Why our number may legitimately differ from a Stocky / Inventory-Planner reconstruction:** | Reason | Direction | Why | | ----------------------- | ---------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------- | | **Velocity window** | Either | We use 30D; Stocky may default to 14D or 60D. Different windows produce different velocity figures. Configurable in *Nerve Centre → Inventory*. | | **Lead-time inclusion** | They include, we don't | Stocky often subtracts vendor lead time from days-cover to give "days until OOS net of incoming". This card is gross days-cover. | | **Trend smoothing** | Different methods | We use simple-mean velocity; advanced apps may use exponential weighting or seasonality adjustment. | | **Multi-location** | Aggregate | We sum across active locations; some apps split per-location. | | **Sync lag** | Either | Inventory updates can lag 5-15 min during heavy write periods. | **Cross-connector reconciliation:** | Card | Expected relationship | What causes legitimate divergence | | ------------------------------------------------------------------------------------------ | -------------------------- | ------------------------------------------------------------------------------------- | | 3PL / WMS forecasting reports | Should align directionally | 3PL forecasts often include lead-time and PO-arrival data which this card doesn't. | | [`amazon_sp.amazon_inventory_velocity`](/nerve-centre/amazon_sp/amazon_inventory_velocity) | Independent | Amazon and Shopify are separate inventory pools unless multi-channel sync is enabled. | ***
Documentation cross-reference (for agencies running multiple platforms) * [`bigcommerce.shp_stock_vs_sales`](/nerve-centre/bigcommerce/shp_stock_vs_sales) * [`adobe_commerce.shp_stock_vs_sales`](/nerve-centre/adobe_commerce/shp_stock_vs_sales)
## Known limitations / merchant FAQs **What's a healthy days-of-cover target?** Depends on your reorder cadence and lead time: * **Fashion DTC with 21-30 day lead times**: target 30-45 days cover on top-velocity SKUs. * **Subscription consumables with 14-day fulfilment cycles**: target 21-30 days cover. * **Slow-fashion with 60-90 day lead times**: target 60-120 days cover. * **Fast-fashion with 7-14 day reorder**: 14-30 days suffices. The right number is "lead time + safety stock + planned promo bumps". A SKU at 14 days cover when lead time is 21 days will OOS regardless of urgency. **Why are some variants excluded from the chart?** Variants with zero sales in 30D have undefined velocity (cover = stock / 0 = infinity). The card excludes them. To see slow-movers, look at [Bottom Products](/nerve-centre/kpi-cards/shopify/slow-moving-products) or [Inventory Distribution](/nerve-centre/kpi-cards/shopify/inventory-distribution) Surplus band. **My new launch SKU shows infinite cover. Why?** Same reason: zero historical sales pre-launch. Once 7-14 days of post-launch sales exist, velocity becomes meaningful. New launches need separate forecasting (typically based on similar past launches, not current data). **Why does seasonality break this card?** The 30D velocity is naive about seasonality. A Christmas-decorations SKU showing 14 days cover in November is a fire (demand surge incoming); the same SKU showing 14 days in February is fine (off-season). Pair with category-specific seasonality calendars. **Can I customise the cover bands?** Yes, in *Nerve Centre → Inventory*. Defaults are ≤7d / 8-14d / 15-30d / 31-60d / >60d. Long-lead-time categories should widen them (≤14d / 15-30d / 31-60d / 61-120d / >120d). **My multi-location store, does cover account for distribution?** The card sums Available across active locations and uses store-wide velocity. A SKU with 100 units in London but 0 in Manchester shows healthy cover, but if Manchester customers can't reach London inventory (no inter-location transfer), the practical cover for Manchester customers is 0. Per-location cover is on the roadmap; for now, plan transfers manually. **Does promotional velocity distort the cover figure?** Yes. A SKU with normal velocity 5/day that sold 50/day during a promo week will show "10/day" 30D average, overstating future depletion. Pair with promotional calendar to discount transient promo-driven velocity. **My subscription SKUs, are they handled correctly?** Subscription billings draw from inventory like one-off orders. The 30D velocity reflects subscriber+one-off blended demand. For pure subscription forecasting, segment subscriber-only velocity from your subscription tool's reports. **Action playbook for using this card:** 1. **Daily ops**: scan the Critical (≤7d) bucket. Reorder or transfer immediately. 2. **Weekly planning**: scan At Risk (8-14d) bucket. Confirm POs are in flight; chase suppliers if not. 3. **Monthly review**: scan Surplus (>60d) bucket. Decide markdown, clearance, or de-list. 4. **Quarterly forecasting**: review velocity-by-SKU trends; tighten PO models for chronic over-orders or under-orders. 5. **Lead-time review**: if Critical bucket is regularly populated, lead times are too long for your safety stock policy. Either widen safety stock or shorten lead times. 6. **Cross-reference with paid media**: pause Google Ads / Meta on Critical-bucket SKUs, see [Active Ads on OOS](/nerve-centre/kpi-cards/shopify/active-ads-on-out-of-stock-skus). *** ### Tracked live in Vortex IQ Nerve Centre *Stock vs Sales Velocity* is one of hundreds of KPI pulses Vortex IQ tracks across Shopify and 70+ other ecommerce connectors. Nerve Centre runs the detection layer; Vortex Mind investigates the cause when something moves; Ask Viq lets you interrogate any number in plain English. [Start for free](https://app.vortexiq.ai/login) or [book a demo](https://www.vortexiq.ai/contact-us) to see this metric running on your own data.