What is AOS?
Average Order Size
Average Order Size (AOS) is the number of items per order. Different from AOV which measures dollar value.
AOS = Total items sold ÷ Total ordersFashion: 1.8-2.5 · Beauty: 2.0-3.0 · Food/grocery: 5-15 · Supplements: 1.2-2.0
Why AOS matters
AOS improvements lower shipping costs per item and improve cart economics. Bundles, BOGO, and volume discounts all raise AOS.
Worked example
Plug a real number into the formula to see AOS in action:
Numbers are illustrative. Try our Shopify Pricing Calculator for your real numbers.
Common mistakes with AOS
- 1
Treating gross revenue as success. Contribution margin per order is what determines viability.
- 2
Counting first-purchase ROAS as the KPI. 90-day LTV ROAS is the operational target.
- 3
Building Shopify theme on platform defaults. Custom blocks and progressive enhancement deliver 15-30% CVR lift typical.
How to improve AOS
Push toward 30%+ contribution margin on every SKU. Anything below subsidizes operations from elsewhere.
Build subscription or replenishment SKUs into 20%+ of revenue. Predictable revenue compounds.
Optimize for repeat-purchase rate as the operating metric. New-acquisition spend should follow LTV, not vanity revenue.
Common questions about AOS
What is AOS?▾
How is AOS calculated?▾
What is a good AOS benchmark?▾
Why does AOS matter for marketing teams?▾
Related terms
Need help applying AOS to your business?
Book a free 30-min audit. We will benchmark your AOS against your industry and flag what to fix first.
Book a free audit