Shopify Inventory Forecasting and Demand Planning

Stockouts and dead stock usually come from the same habit: reordering on gut feel from last month's sales. Both cost cash, one in missed sales and the other in stock that won't sell. Shopify gives you the raw material — sell-through, ABC analysis and inventory remaining reports — but no automated demand-forecasting tool.

Shopify inventory forecasting work turns that history into a forecast by SKU, reorder points set from real supplier lead times, and purchase plans your team can run every week. It's planning, not stock control. Day-to-day inventory management and wider supplier and freight work are separate services.

Stocky was retired on 31 August 2026, so brands that planned purchases in it need a new routine. A quote request with your catalogue size, supplier lead times and current planning method is enough to price a one-off forecast or a full routine.

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How to choose a demand planning consultant

Ask what you'll be left with. The deliverable should be a routine and a sheet or tool your team keeps using after the engagement ends. A forecast delivered once as a slide deck is out of date by the next purchase order.

Check how they clean the history. Ask how they treat weeks when a SKU was out of stock and weeks with a promotion. A planner who forecasts straight from raw sales will under-buy best sellers that ran out and over-buy anything that once sold on discount.

Ask for a worked example on one of your SKUs. Weekly demand, supplier lead time, safety stock, reorder point. If they can't explain the maths in plain language, your buyer won't be able to use it.

Look for buying experience, not just spreadsheet skill. The strongest planners have bought stock against a budget and lived with the result. Ask how they handle seasonality, launches and supplier minimum order quantities.

Ask how they forecast launches. New products have no sales history, so a planner should explain how they borrow from similar SKUs or past launches, and when they switch to real sales data. A plan that ignores launches is wrong exactly when the stakes are highest.

Don't pay for a subscription dressed up as a plan. If the main deliverable is a software licence, you're buying a tool, not planning. Be just as wary of a forecast with no monthly check against actual sales, or an accuracy figure quoted up front.

Let catalogue size decide between a spreadsheet and a tool. A 50-SKU brand with two suppliers needs a clean spreadsheet and a weekly habit. Hundreds of SKUs across several suppliers and locations may justify a planning tool, which a consultant should help you choose rather than resell.

How ecommerce inventory forecasting works week to week

Start from Shopify's reports. Sell-through rate shows what share of stock sold in a period, ABC analysis grades each variant by its share of revenue over the last 28 days, and inventory remaining per product estimates how long stock will last at current sales rates. Export them on the same day each week; nothing in Shopify turns them into a forecast for you.

Clean the history. Out-of-stock weeks hide demand, so replace them with a normal-week estimate. Promotions inflate it, so flag those weeks and plan future promotions separately.

Forecast at the right level. Forecast A items by SKU. Group slow C items by product family, then split the total by size or colour mix.

Add what you know is coming. Seasonality, planned promotions, launches and wholesale orders sit on top of the baseline.

Set reorder points from real lead times. A SKU selling 40 units a week from a supplier with a six-week lead time needs a reorder point of 240 units plus safety stock. Use the lead times suppliers actually deliver, not the ones on the quote.

Turn the plan into orders and a budget. Purchase orders, suppliers and transfers are native in Shopify, so the plan becomes real POs rather than a separate list. An open-to-buy budget caps what you commit each month.

Review monthly. Check forecast against actual by SKU, fix the biggest misses and write down why they happened.

How much does inventory planning help cost?

Start with what you already pay for, then decide how much outside help the catalogue needs. Typical market ranges:

Forecasting project

$1,000 – $12,000

From a forecast model to a full planning system

Planning or supply chain consultant

$100 – $400

Per hour, independent specialists at the top

Shopify inventory reports

Included

ABC analysis, sell-through, inventory remaining

The low end of the project range buys a forecast model for a small catalogue. The top end covers a full planning system: SKU forecasts, reorder points, an open-to-buy budget and team training. Boutique planners with a retail buying background tend to start around $6,000.

The hourly range reflects general supply chain consulting rates, and a narrow forecasting brief needs fewer hours than a full supply chain review. SKU count, the number of suppliers and locations, and the state of your sales history move the price most.

The quote gets precise when a planner can see your SKU count, a year of weekly sales by SKU, and each supplier's lead time and minimum order quantity.

What a demand planner builds for a Shopify brand

Shopify inventory planning work usually produces six things:

Clean sales history

Stockout gaps filled, promotion spikes flagged, discontinued SKUs removed

SKU-level forecast

Weekly or monthly demand with seasonality and planned promotions

Reorder points and safety stock

Set per SKU from real supplier lead times

Purchase plan

The forecast turned into Shopify purchase orders on a set cycle

Open-to-buy budget

Monthly spending limits by category, agreed with finance

Forecast review

A monthly forecast-versus-actual check, with adjustments

Frequently asked questions about Shopify inventory forecasting

Does Shopify have an inventory forecasting tool?

Not an automated one. Shopify supplies the inputs and the ordering side: inventory reports to export, and purchase orders you raise in the admin. The forecast itself has to come from a spreadsheet, a planning tool or a planner. For a catalogue of a few hundred SKUs or fewer, a well-built spreadsheet fed by weekly report exports is usually enough.

What is open to buy, and does a Shopify brand need it?

Open to buy is the budget left for new stock in a period: planned sales plus planned closing stock, minus opening stock and stock already on order. It stops a brand committing next season's cash to reorders of this season's lines. Once you place orders for more than one season at a time, it's worth having; below that, reorder points usually do the job.

What's the difference between inventory planning and replenishment planning?

Inventory planning sets how much stock you should hold and buy over a season, by category or SKU, against a budget. Replenishment planning is the weekly job of topping up ongoing lines: checking stock against reorder points and raising purchase orders or transfers. Most brands need the first each quarter and the second every week. A planner should set up both and hand the weekly part to your team.

How is ecommerce demand forecasting different from store-based retail?

Online demand moves with promotions, email campaigns, ads and marketplace listings, and you see it day by day rather than store by store. The upside is cleaner data: every order carries a date, product and channel. The risk is reacting to noise. Forecast weekly, flag every campaign in the history, and don't change reorder points on the back of one strong week.

How much safety stock should I hold?

Enough to cover the gap between a normal week and a bad one while you wait for the supplier. Base it on how much weekly sales vary and how much lead times slip, and hold more for A items you can't afford to run out of than for slow C items. Flat rules like two extra weeks for everything tie up cash in slow lines; set it per SKU instead.

Can I forecast inventory across several locations?

Yes, but forecast total demand first and split it by location second. Shopify tracks stock per location and handles transfers natively, so a plan can move stock between locations as well as buy more. If a 3PL or another tool also holds reorder rules, agree which system raises purchase orders so the same stock isn't ordered twice.