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ABC class (A / B / C)

5 min read

Tendlio sorts your products into three classes by revenue: class A brings in most of it, class B comes next, and class C shares what’s left. The class tells you which products matter most to your sales, including the ones that don’t sell many units.

The three classes #

  • A: the products that together bring in about 80% of your revenue. Class A isn’t the same as fast: a pricey product that sells a few times a month can be A.
  • B: the products that bring in the next 15% or so.
  • C: the products that share the last 5% or so. C also holds every product that hasn’t sold in the last 12 months.

How Tendlio works out the classes #

For each product, Tendlio works out a revenue figure: the units it sold in the last 12 months times its price at your last analysis (the sale price, if it was on sale). For a product you listed less than a year ago, Tendlio uses the pace it has sold at since you listed it, as if it had sold at that pace all year.

At each analysis, Tendlio lists your products from the biggest figure down and keeps a running total as it goes. Class A runs from the top until the running total reaches 80% of the total for all your products, class B runs on until it reaches 95%, and class C is everything after that.

So ABC ranks your products by units sold and current prices, not by what your orders added up to. A product you sold at a discount last spring counts at its price today, and the months a product spent sold out count as months without sales.

Where you see the class #

  • Products & insights: the ABC column, and the ABC filter over the table, which shows one class at a time. Hover over a letter in the column to read what its class means. The Catalog filter also has Long tail (B + C, still selling): the B and C products that sold at least once in the last 12 months.
  • The Restock page: an ABC column in What’s running low.
  • Reports → Best sellers and Reports → Out of stock: an ABC column. Reports → Categories shows how many A, B and C products each category has.
  • A product’s Insights page, under ABC class.

What Tendlio uses the class for #

  • The To do card about best-sellers running low on stock counts only products in classes A and B. The line under its title calls them the products that bring in most of your revenue.
  • On Products & insights, a sold-out product gets a RESTOCK badge under its name when it’s class A, or when it was selling Fast or Steady.
  • A few other To do cards look only at class A, or at A and B, and the price test, an Experimental feature, suggests only class A products to test.

What to do with each class #

  • A and B: keep them in stock, class A first. On the Restock page, click the ABC column title in What’s running low to see your A products together.
  • C: before you reorder a C product, check how much of it you already hold. If you’re thinking of dropping some products, open Is the bottom of your catalog worth its cost? on Products & insights. Its calculator compares what your lowest earners bring in with what they cost you to carry, and the section shows once your catalog has 50 products or more.

Why ABC works this way #

Why revenue and not units #

ABC ranks by money, so the products your revenue depends on come first. Counting units instead would put a $5 product that sells 20 a month ($100) above a $200 product that sells two a month ($400).

Why a product can be Slow and class A #

The health color counts units, and ABC counts money. A pricey product that sells a few a month can be Slow and class A at the same time: it sells slowly, and it’s still one of your top earners. Check its margin, stock and season before you treat it as a slow seller.

Why ABC and Revenue/mo can disagree #

ABC spreads a product’s sales over the whole year, so the months it spent sold out count as months without sales. The Revenue/mo column on Products & insights leaves those months out and shows what the product earns in a month while it’s in stock. So a product that was sold out for part of the year can have a high Revenue/mo and still be class B or C.

Additional resources #

Frequently asked questions #

Why is a product that sells every day class C? #

ABC counts money, not units. A cheap product can sell every day and still bring in only a small share of your revenue.

Why isn't the split exactly 80 / 15 / 5 in my store? #

Each class ends at the product that takes the running total past the line, so a class can hold a little more than its share.

Can I change where the classes stop? #

Not in Tendlio's settings, and the split is the same whatever Store vertical you picked.

Does ABC use profit? #

No, it uses revenue. For profit, sort Products & insights by Profit/mo, which needs a cost price, or the average margin you set in Settings.

Updated on September 28, 2026