Sell-Through Rate: Formula, Calculator and What's Good
Sell-through rate is the percentage of the stock you had that you actually sold in a given period. If you started the month with 200 units of a product and sold 120 of them, your sell-through rate for the month is 60%.
It is one of the simplest inventory metrics, and one of the most useful. It tells you which products are moving, which are sitting on the shelf tying up cash, and whether your next order should be bigger or smaller.
The sell-through rate formula
There are two common versions. They answer slightly different questions, so it is worth knowing which one you are looking at.
Based on stock received (common in retail buying):
Sell-through rate = units sold ÷ units received × 100
Use this when you want to judge a specific delivery or buy: of the 500 units that arrived for the season, how many have gone?
Based on stock available (better for ongoing ecommerce lines):
Sell-through rate = units sold ÷ (units sold + units still in stock) × 100
Units sold plus units left is the stock you had available during the period, so this version works even when you restock continuously and never think in terms of one delivery. It is the version Ask AI uses.
Pick a fixed period and stick to it. Monthly (30 days) is the most common, and it is what most retailers mean when they quote a sell-through rate.
Sell-through rate calculator
Sell-through rate calculator
60%
Healthy. Most of what you stocked is moving.
A worked example
Say a store sells three products over 30 days (illustrative numbers):
| Product | Units sold | Units left in stock | Sell-through rate |
|---|---|---|---|
| Linen tote | 180 | 20 | 90% |
| Canvas apron | 90 | 60 | 60% |
| Embroidered cushion | 15 | 135 | 10% |
The tote is close to selling out, so the risk there is running out of stock. The apron is moving at a steady pace. The cushion has barely moved, and 135 units of cash are sitting in the stockroom.
Looking at revenue alone, the cushion might not stand out at all. Sell-through rate makes the problem obvious.
What is a good sell-through rate?
It depends on the product and the period, but the commonly quoted ranges for a 30-day period are:
- Above 80%: strong demand. Check you are not about to run out.
- 60% to 80%: healthy for most products.
- 40% to 60%: slow. Worth a closer look.
- Below 40%: likely overstocked or underperforming.
Lightspeed describes a consistent sell-through rate of 75% or more as strong, and 60% to 80% as generally healthy.
Context matters. Seasonal and fashion products need a high sell-through before the season ends, because leftover stock loses value fast. Staple products you reorder every month can run at a lower rate without any problem, as long as you are not overbuying.
A very high rate is not automatically good either. A product at 98% sell-through every month is probably selling out and losing you sales while it is out of stock.
How to improve sell-through rate
- Order less, more often. Smaller, more frequent orders keep stock in line with demand and raise sell-through without losing sales.
- Act on slow sellers early. A product at 20% after two weeks rarely recovers on its own. Move it up your homepage, bundle it with a best seller, or promote it to customers who bought something similar.
- Fix the product page. Low sell-through with plenty of traffic usually means a price, photo or description problem rather than a demand problem.
- Check the variants. A product can look healthy overall while one size or colour sits unsold. Calculate sell-through by variant, not just by product.
- Use it when you reorder. Products with consistently high sell-through deserve bigger orders. Consistently low ones deserve smaller orders, or none.
Sell-through rate vs inventory turnover
The two are related but not the same. Sell-through rate is a percentage for one period: how much of the available stock sold. Inventory turnover is how many times you sell through your average stock in a year. Sell-through is easier to act on week to week. Turnover is better for comparing your inventory efficiency with other businesses.
Getting sell-through rate from your own data
Working this out by hand means exporting sales and inventory reports and lining them up in a spreadsheet, product by product.
If you connect your store to Ask AI, you can ask your AI assistant directly. Ask AI calculates sell-through from your Shopify or WooCommerce orders and current inventory, alongside days of stock left and inventory turnover. You can ask things like:
- "Which products had a sell-through rate under 30% in the last 30 days?"
- "Which best sellers are about to run out of stock?"
- "Show me sell-through by variant for our top 10 products."
It works in Claude, ChatGPT, Gemini and Perplexity. You can try the live demo without an account.
FAQ
What is sell-through rate?
The percentage of available stock you sold in a period. If you had 200 units and sold 120, your sell-through rate is 60%.
How do you calculate sell-through rate?
Divide units sold by units received (or by units sold plus units left in stock), then multiply by 100. Use a consistent period, usually 30 days.
What is a good sell-through rate?
For a 30-day period, 60% to 80% is commonly considered healthy and 80% or more is strong. Below 40% usually means a product is overstocked or underperforming.
Is a high sell-through rate always good?
No. A rate close to 100% every period often means you are selling out and missing sales while out of stock. Pair it with days of stock remaining.