Keep overlapping discounts clear

Buy 2 get 1 free, free shipping, and a VIP code should not turn into a confusing cart. This guide explains how Atom Discounts keeps discount behavior predictable when offers overlap.

Why this matters

The value is simple: shoppers should understand the deal, and your team should know which discount will apply before a campaign goes live.

Atom Commerce uses a clear evaluation order so discounts do not pile up unpredictably or erase margin by accident.

Evaluation order

1. Item-Level
Discounts applied to specific products or product lines
2. Order-Level
Discounts applied to the entire order based on subtotal
3. Shipping-Level
Discounts applied to shipping costs

Priority Within Each Class

Within each offer class, higher-priority offers evaluate first. This ensures the most important discounts take precedence.

Key Rules

  • One item-level discount per product line: Only the highest-priority item discount applies
  • Order-level evaluates on post-item subtotal: After item discounts are applied
  • Shipping-level evaluates last: After both item and order discounts

Stacking Rules

Stacking determines which offer classes can combine together. This prevents margin erosion while allowing strategic combinations.

Common Stacking Patterns

Item + Order (Recommended)

Volume discount + order threshold discount

Item + Shipping (Recommended)

Product discount + free shipping threshold

Order + Shipping (Recommended)

Order discount + shipping discount

Example Scenarios

Scenario 1: Volume + Order Threshold

Setup: 10% off collection A (item-level, priority 90) + 10% off orders $140+ (order-level, priority 80)

Cart: $150 in collection A products

Result: Item discount fires first → subtotal becomes $135 → order-level no longer qualifies


Scenario 2: Clean Stacking

Setup: 15% off collection A (item-level, priority 90) + Free shipping $75+ (shipping-level, priority 80)

Cart: $100 in collection A products + $10 shipping

Result: Item discount → $85 subtotal → Free shipping applies → Final total: $85

Best Practices

  • Set clear priorities: Use distinct priority numbers (90, 80, 70) to avoid conflicts
  • Test boundary cases: Try carts just below and above thresholds
  • Use combinations intentionally: Allow stacking only where it adds value
  • Document your rules: Keep a simple table of active offers and their settings
  • Set end dates: Prevent legacy promotions from interfering with new campaigns

Common Questions

How does Atom Discounts evaluate Shopify discounts?

Atom Discounts evaluates item-level offers first, then order-level offers, and finally shipping-level offers so discount outcomes stay predictable.

Can Shopify item-level and order-level discounts stack in Atom Discounts?

Yes, when combinations are allowed. Item-level offers evaluate before order-level offers, so the order-level minimum is checked against the post-item-discount subtotal.

Why is offer priority important for Shopify discounts?

Priority determines which discount evaluates first within the same class, which helps teams prevent accidental double-discounting and choose the intended winning offer.

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