Quick Commerce Stock Cover Calculator for Blinkit, Zepto & Instamart

How to use the quick commerce stock cover calculator

1. Enter your stock. Add units at the platform and units in transit, either as a total or per dark store.
2. Add daily sales. Use average daily sales across all stores, plus any uplift you expect for a promotion or festive sale.
3. Add lead time and target cover. Enter how many days a new consignment takes, how often you dispatch and how many days of cover you want after it arrives.
4. Choose a safety stock method. Use days of demand for a quick estimate, or a service level if you know how much daily sales vary.
5. Read your plan. Check days of cover, reorder date, units to send and the shelf-life check before you raise the next dispatch.

What is stock cover in quick commerce?

Stock cover in quick commerce is the number of days a brand’s current stock on Blinkit, Zepto or Swiggy Instamart will last at its average daily sales. It is also called days of cover or stock coverage. A SKU with 1,500 units available and 80 units sold a day has about 18.8 days of cover.

Stock cover tells you two things at once: how soon you could run out, and whether you are tying up too much stock in dark stores. Too little cover means empty shelves and lost orders. Too much cover means cash locked in inventory, higher storage costs and more risk of expiry.

Stock cover formulas at a glance

Every stock cover decision comes down to six formulas. The calculator above runs all of them at once.

How do you calculate days of stock cover?

Divide your available stock by your average daily sales. Include stock already in transit to the platform if it will arrive before your current stock runs out, and increase daily sales by the expected uplift for any promotion.

Step by step:

1. Daily demand = average daily sales × (1 + promo uplift %)
2. Days of cover = (units at platform + units in transit) ÷ daily demand
3. Stockout date = today + days of cover
4. On-hand cover = units at platform ÷ daily demand. This shows your risk if the in-transit consignment is delayed.

How much safety stock do you need for dark stores?

Safety stock is the extra stock you hold to cover sales spikes and delivery delays. The simple way is to hold a fixed number of days of demand, such as 5 days. The more accurate way uses your target service level and how much daily sales vary: safety stock = z × standard deviation of daily sales × √lead time.

Example: with daily sales varying by 20 units, a 7-day lead time and a 95% service level, safety stock = 1.65 × 20 × √7 ≈ 88 units. Higher service levels protect availability but need more stock, so hold the highest levels for hero SKUs and fast sellers, and lower levels for slow or short shelf-life products.

What is a reorder point and when should you reorder?

The reorder point is the stock level at which you should raise your next dispatch so new stock arrives before you run out. Calculate it as daily demand × lead time + safety stock. At 80 units a day, a 7-day lead time and 400 units of safety stock, the reorder point is 960 units.

When your available stock (including in-transit) falls to the reorder point, send the next consignment. Above it, you have time. Below it, you are already using safety stock, and any delay at the warehouse can leave dark stores empty.

How many days of stock cover should you keep?

There is no single platform-wide number. A practical range is set by two limits: keep at least lead time + safety days + the days between your dispatches, and keep no more than about one third of the product’s remaining shelf life. Anything below the minimum risks stockouts; anything above the maximum risks expiry.

The one-third rule is our planning guideline, not a platform requirement. Always check the minimum remaining shelf life your category needs at inwarding.

Worked example 1: snack SKU across 40 dark stores

Assumptions: 40 active dark stores holding 30 units each (1,200 units), 300 units in transit, 2 units sold per store per day (80 a day in total), 7-day lead time, 5 days of safety stock, 7 days between dispatches, 21-day target cover, case pack of 24, 2% wastage, 90 days of remaining shelf life.

What it means: Raise the next dispatch within 6 days. Sending 192 units brings cover to just over 21 days, inside the suggested range and using less than a quarter of the remaining shelf life, so expiry risk is low. If a 25% festive uplift is expected, the same stock lasts only 15 days and the reorder window drops to 3 days.

Worked example 2: why total stock cover can hide dark store stockouts

Total stock cover is an average. In quick commerce, some dark stores sell much faster than others, so they run out long before your total cover suggests. Always check cover for your fastest stores, not just the total.

Same 40 stores, 30 units each, 80 units sold a day in total, but demand is uneven:

The total says 15 days, but a quarter of your stores will be empty in about a week, while the slow stores hold more than three weeks of stock. Fix this by asking for higher allocation to fast stores, sending smaller and more frequent consignments, and reducing stock in slow stores rather than adding more overall.

Stock cover vs days of inventory vs weeks of supply

Stock cover, days of inventory and weeks of supply all describe how long stock lasts, but they are used differently. Stock cover and weeks of supply look forward using expected sales. Days of inventory (DOI) usually looks back using accounting data.

Why is dark store inventory different from marketplace inventory?

Quick commerce platforms deliver from many small dark stores close to shoppers, not from a few large warehouses. Each dark store holds only a small amount of each SKU, so local demand, store-level availability and replenishment speed matter far more than on Amazon or Flipkart.

1. Availability is local. A shopper only sees stock in the dark store that serves their area. Your total stock can look healthy while several stores are empty.
2. Space is tight. Dark stores carry limited stock per SKU, so overstocking one store rarely helps another.
3. Out of stock hurts discovery. When a product is unavailable in a store, it cannot be ordered there, and lost sales also weaken how often the product appears in search and recommendations.
4. Shelf life matters more. Food, beverage and personal care products turn over at different speeds by store, so slow stores build expiry risk.

Understock vs overstock: what each costs you

What is fill rate in quick commerce?

Fill rate is the share of ordered units a supplier actually delivers. In quick commerce, it usually means how much of a platform’s purchase order or stock request a brand fulfils on time. Fill rate = units delivered ÷ units ordered × 100. If a platform requests 1,000 units and you deliver 920, your fill rate is 92%.

Low fill rates leave dark stores short of stock, which means lost sales and weaker availability across cities. Planning stock cover, safety stock and reorder dates with this calculator helps you keep enough inventory ready to fill every request in full.

How to plan stock for festive sales and promotions

1. Add uplift early. Enter the expected demand increase as a percentage so cover and reorder dates reflect the event, not normal days.
2. Expect longer lead times. Warehouses and transport slow down in peak season, so add a few days to your normal lead time.
3. Raise safety stock for hero SKUs. Use a higher service level for products that drive most of your sales or ads.
4. Check shelf life before you scale. A bigger festive dispatch must still sell well before expiry once demand returns to normal.
5. Pause ads where stock is thin. Ads on products that are running out waste budget. Check your break-even ROAS before increasing spend.

6 common stock cover mistakes on quick commerce

1. Planning only on total stock. Fast dark stores run out first. Check store-level cover for your top stores.
2. Ignoring in-transit delays. Count in-transit stock, but watch on-hand cover in case a consignment is held at inwarding.
3. Using last month’s average during a sale. Add festive or promo uplift, or cover will be overstated.
4. Same safety stock for every SKU. Hero SKUs need more; slow, short shelf-life SKUs need less.
5. Rounding down to save cost. Units to send should round up to full cases, or you fall short of target cover.
6. Sending more than shelf life allows. Large dispatches of perishable products turn into wastage and returns.

Stock cover and safety stock formulas for Excel or Google Sheets

Set up one row per SKU with these columns: B = units at platform, C = units in transit, D = average daily sales, E = lead time (days), F = safety days, G = target days of cover, H = case pack, I = safety stock, J = reorder point, K = wastage % (as a decimal), L = standard deviation of daily sales.

These formulas work in both Microsoft Excel and Google Sheets. Use the calculator above to check one SKU, and the sheet to plan your full range.