How to calculate supply on Ozon?

Supply planning for Ozon is based on how much product will sell before the next batch arrives. This takes into account sales velocity, current remaining stock, and all lead times until warehouse replenishment: production (or procurement) and delivery.

What data is needed to calculate a supply for Ozon

To calculate a supply for Ozon, you need to gather specific figures in advance. The more accurate the data, the lower the risk of stockouts.

For calculating a supply, you will need:

Current remaining stock

How many units are currently available for sale at the Ozon warehouse (and, if necessary, at your own warehouses).

Average daily sales

How many units of the product sell on average per day. This is usually calculated based on sales history from recent days or weeks, excluding obvious anomalies.

Production or procurement lead time

How many days pass from the moment you place an order for production/procurement until the batch is ready for shipment.

Delivery time to the Ozon warehouse

How many days logistics takes: from dispatch from your warehouse to the actual availability of the product at Ozon.

The period for which you need to stock the warehouse

The number of days you want to guarantee product availability without stockouts after the new batch arrives.

Based on these metrics, you can calculate a supply with clear logic and minimize errors.

Step-by-step calculation of supply volume

The supply volume is calculated through a sales forecast for the period while the new batch is in transit and being processed. First, you find out how many products will be sold during the time before replenishment, then subtract the current remaining stock to get the required supply volume.

Algorithm for calculating supply:

Calculate the total period in days that needs to be covered by stock

This includes:

production (or procurement) lead time;

delivery time to the Ozon warehouse;

an additional period for which you want to have product in stock after the batch arrives.

Multiply average daily sales by this period

This is the forecast of how many units of the product will be sold during that entire time.

Subtract current remaining stock

The difference will be the approximate volume of the next supply.

Calculation example

Given:

average sales — 15 units per day;

production — 7 days;

delivery to Ozon warehouse — 5 days;

the warehouse needs to be stocked for another 30 days after the new batch arrives;

current remaining stock — 250 units.

Step 1. Calculate the total period: 7 (production) + 5 (logistics) + 30 (stock period) = 42 days.

Step 2. Sales forecast for this period: 15 × 42 = 630 products.

Step 3. Account for current remaining stock: 630 – 250 = 380 units.

Total: the approximate volume of the next supply is about 380 products. In practice, this figure is adjusted considering seasonality, ad campaigns, participation in promotions, and expected growth or decline in demand.

Why you can't rely only on remaining stock

Relying solely on remaining stock without a sales forecast and supply lead times is risky. A product may run out before the new batch arrives, even if the warehouse currently seems "full."

What happens with this approach:

With a sharp increase in demand or a supply delay, stock depletes faster than expected. The product listing goes out of stock, product visibility drops, and turnover decreases. When the product returns to stock, positions and sales do not recover immediately: algorithms and buyers need to "warm up" again.

To avoid this scenario, you need to:

regularly calculate how many days the current remaining stock will last at the current sales velocity;

estimate the date when the product will run out;

compare it with the date when the next batch will actually arrive;

start production/procurement and supply in advance, while there is still time before a stockout.

What factors influence supply volume

The supply volume cannot be calculated based only on current sales velocity and remaining stock. Demand is affected by a whole set of factors that distort the basic figures.

The main ones:

Seasonality

For some products, demand spikes sharply during certain periods (holidays, school year, gardening season, etc.). During these windows, daily sales can differ from annual averages by several times.

Promotions and sales

Participation in marketplace promotions or your own discounts usually boost sales. Before a major sale, it makes sense to increase the supply volume.

Ad campaigns

Launching advertising (internal and external) leads to additional traffic and increased purchases. If you calculate based on the "old" sales velocity, the product may go out of stock.

Sales dynamics

If there is a steady increase or decrease in demand, the sales forecast needs to be adjusted, rather than assuming "tomorrow will be like yesterday."

Production and logistics lead times

The longer the supply cycle, the earlier you need to start the next batch and the larger the stock (in days) it must cover.

Safety stock

A small reserve for unexpected demand spikes helps avoid stockouts even with forecast errors.

How to automate supply calculation in Torgstat

With a large assortment, manually calculating supplies for each SKU becomes difficult and time-consuming. For each item, you need to track its own remaining stock, sales velocity, and supply lead times. Automation removes this routine.

The Torgstat service has a separate supply calculation tool that does this automatically. You set the key parameters, and the system calculates recommended supplies.

The following values are configurable:

Turnover period

How many days in advance you want to stock the warehouse. This is the target horizon that the stock should cover.

Calculation basis

The calculation can be based on all orders or only redeemed ones.

Sales velocity coefficient

A number used to adjust the current sales velocity considering plans.

Number of units per box

Expected sales period

The time interval for which the required stock in units is calculated. This is the basis of the forecast for how much product will be needed.

Logistics and production lead time

The total number of days from the decision to supply to the product being available at the Ozon warehouse.

Supply date

The tool outputs:

the recommended supply volume for each product;

an estimate of how many days until current remaining stock runs out;

helps plan the shipment of a new batch in advance and avoid stockouts.

This approach eliminates manual formulas, speeds up decision-making, and is especially useful when many SKUs are listed on Ozon.

Common mistakes when calculating supply for Ozon

The main issues in supply management are related to systematic errors in calculations and planning. They can be anticipated and avoided.

Sellers most often:

Calculate supply based only on current remaining stock

They do not consider how long this stock will last at the current sales velocity and when the next batch will actually arrive.

Forget about production and delivery lead times

With a long supply cycle, launching a new batch often happens too late, and the product runs out.

Do not account for sales growth after advertising

They plan supplies based on old metrics, even though advertising activity sharply accelerates sales.

Send the same volume every time

They ignore changes in demand, seasonality, and new conditions, as if the market is "frozen."

Do not maintain safety stock

Any fluctuation in demand or logistics disruption immediately leads to a stockout. The result is either the product disappears from the shelf and sales drop, or money is tied up in excess stock and storage costs increase.

Frequently asked questions

How do I know when it's time to make a supply for Ozon?

A supply should be planned as soon as it becomes clear that current remaining stock will not last until the next batch arrives, considering:

current sales velocity;

production or procurement lead time;

delivery time to the Ozon warehouse.

If the calculation shows that the product will run out before replenishment arrives, the supply launch cannot be delayed.

How often should I recalculate the supply volume?

Recalculating the supply volume is advisable every time demand or sales conditions change significantly, including:

when launching or stopping advertising;

when a product participates in major promotions and sales;

when there is a noticeable price change;

during seasonal growth or decline in demand.

The more dynamic the niche, the more often the forecast needs review and updating.

Can the supply be calculated automatically?

Yes, supply calculation can be automated. Torgstat has a separate Supply Calculation tool for this. To use it, you just need to set:

turnover period;

calculation basis: all orders or redeemed products;

sales velocity coefficient (accounting for expected growth or decline in demand);

expected sales period;

number of units per box;

logistics and production lead time;

supply date.

Based on these parameters, the service automatically calculates the recommended supply volume for each product, estimates the time until stock depletion, and helps build stable supplies without stockouts or excess.