> ## Documentation Index
> Fetch the complete documentation index at: https://docs.upstackdata.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ATC to IC Rate: Cart to Checkout Conversion

> Measure the percentage of cart additions that proceed to checkout. Identify cart abandonment issues and optimize the path from cart to purchase.

<Tip>
  ATC to IC Rate measures the percentage of add-to-cart events that progress to initiate checkout.
</Tip>

## Formula

<Info>
  **ATC to IC Rate** = ( **Initiate Checkouts** ÷ **Add to Carts** ) × 100
</Info>

### Formula Components

| Metric                                                                            | Definition                               |
| --------------------------------------------------------------------------------- | ---------------------------------------- |
| [**Initiate Checkouts**](/reference/metrics/funnel/engagement/initiate-checkouts) | Total checkout initiation events tracked |
| [**Add to Carts**](/reference/metrics/funnel/engagement/add-to-carts)             | Total add-to-cart events tracked         |

| Metadata        |                         |
| --------------- | ----------------------- |
| **Type**        | Percentage              |
| **Data Source** | [Upstack Pixel](/pixel) |
| **Aggregation** | Ratio                   |

***

## Example

Your store tracked **1,521 add-to-cart events** in January, with **912 progressing to checkout**.

| Metric             | Value     | Calculation         |
| ------------------ | --------- | ------------------- |
| Add to Carts       | 1,521     | Items added to cart |
| Initiate Checkouts | 912       | Checkout starts     |
| **ATC to IC Rate** | **60.0%** | (912 ÷ 1,521) × 100 |

***

## How It Works

ATC to IC Rate calculates the conversion between cart addition and checkout initiation. The Upstack Pixel tracks add-to-cart events when visitors add products and initiate checkout events when they begin the checkout process.

***

## When to Use

| Scenario                    | Action                                       |
| --------------------------- | -------------------------------------------- |
| Cart experience audit       | Identify friction preventing checkout starts |
| Shipping threshold testing  | Measure impact of free shipping offers       |
| Trust signal optimization   | Test security badges, reviews, guarantees    |
| Mobile vs. desktop analysis | Compare checkout intent by device            |

***

## Related Metrics

| Metric                                                                                    | Relationship                            |
| ----------------------------------------------------------------------------------------- | --------------------------------------- |
| [Add to Carts](/reference/metrics/funnel/engagement/add-to-carts)                         | Denominator — cart additions            |
| [Initiate Checkouts](/reference/metrics/funnel/engagement/initiate-checkouts)             | Numerator — checkout starts             |
| [Add to Cart Rate](/reference/metrics/funnel/engagement/add-to-cart-rate)                 | Previous funnel step — views to cart    |
| [Checkout Conversion Rate](/reference/metrics/funnel/engagement/checkout-conversion-rate) | Next funnel step — checkout to purchase |

[See all Engagement metrics →](/reference/metrics/funnel/engagement)