> For the complete documentation index, see [llms.txt](https://help.littledata.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.littledata.io/integrations/facebook-capi/custom-metrics-in-meta-reporting.md). # Custom metrics in Meta reporting Custom metrics in Meta are created right in the reporting table. (In GA4 you set up [calculated metrics](https://help.littledata.io/google-analytics/behavior/ga4-calculated-metrics-that-improve-understanding-of-ecommerce-performance) in Admin instead.) {% stepper %} {% step %} ### Open the Custom tab In Meta Ads Manager, open **Customize columns** and choose the **Custom** tab. ![](https://3956158252-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1QhTbrMraNWciQeDvu1b%2Fuploads%2Fgit-blob-bb111c259c10d5ad5ab0076f10d404f3e0b02539%2Fcustom-metric.png?alt=media) {% endstep %} {% step %} Build the formula Click **Create custom metric**. Use **Select metric** and the math buttons to build your formula. {% endstep %} {% step %} ### Choose who can use the metric Give the metric a **Name** and pick a **Format**, such as Percentage or Currency. Under **Who can access this?**, choose whether the metric is only for you or shared with others in the ad account. ![](https://3956158252-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1QhTbrMraNWciQeDvu1b%2Fuploads%2Fgit-blob-f09618ee2510519dc0c5716d0b04257af7262c09%2Foptions-for-custom-meta-metrics.png?alt=media) {% endstep %} {% step %} **Create the metric** Click **Create metric**. The new column is now available for your campaigns, ad sets and ads. {% endstep %} {% endstepper %} {% hint style="info" %} Meta reporting is event-based, not user-based. Use these metrics to compare campaigns, ad sets and ads against each other, not as exact numbers. {% endhint %} In this article we'll show you 6 powerful custom metrics for e-commerce Meta reporting that are not available by default, along with their formulas and specific use cases. ## Cart-to-buy ratio The share of add to cart events that end in a purchase. Meta doesn't offer this metric by default. Formula: Cart-to-buy ratio = Purchases ÷ Adds to cart (format: Percentage) ![](https://3956158252-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1QhTbrMraNWciQeDvu1b%2Fuploads%2Fgit-blob-6481e1deafd85bfcae6e5067a57f710e9604b36e%2Fcart-to-buy-ratio.png?alt=media) This compares all add to carts with all purchases, not shoppers. For example, if someone adds 5 items to the cart and buys all of them in one order, the ratio shows 20%. It works best when you compare ads or campaigns that promote similar products. {% hint style="success" %} Keep the **Adds to cart** column next to it. It shows how much volume is behind each row. {% endhint %} ### Littledata events you can use The next metrics use Littledata's own purchase events. These are sent to Meta as custom events: | Event in Meta | What it is | How you get it | | ------------------------------------------ | ---------------------------------------- | ---------------------------------------------- | | `New Customer Purchase - Littledata` | A customer's first order | Add the **New customer purchase** recipe | | `Returning Customer Purchase - Littledata` | A repeat order or a subscription renewal | Add the **Returning customer purchase** recipe | | `First Recurring Purchase - Littledata` | The first order of a new subscription | Add the **First recurring purchase** recipe | | `Recurring purchase` | A subscription renewal | Add the **Recurring purchase** recipe | | `Post purchase upsell` | A post-purchase upsell added to an order | Sent automatically | Except for **Post purchase upsell**, these events are [recipes](https://help.littledata.io/event-editor/recipes) in the Meta destination's Event Editor. If your store already sent these events before they became recipes, they were kept for you and show in your Event Editor events list. {% stepper %} {% step %} #### Open the Event Editor In the Littledata app, find the Meta card. Click the **⋯** menu and choose **Settings**. Then open the **Event Editor** tab. {% endstep %} {% step %} #### Add the recipes you need In **Recommended for your store**, click **Preview** on a recipe. Then click **Add event**. {% endstep %} {% endstepper %} ## Customer acquisition cost (CAC) Calculating this metric is simple, right? CAC = Amount spent / New Customers acquired Only problem is that New customers is NOT measured in Meta ads. Unless you use Littledata connector :) ![](https://3956158252-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1QhTbrMraNWciQeDvu1b%2Fuploads%2Fgit-blob-498755556ab12d137cd4d36b4b73222447742ab4%2Fmeta-custom-metrics-post---events.png?alt=media) Apart from the standard events we see here - there are 5 more events being sent to your Meta account if you're using Littledata CAPI connector: * Returning customer purchase * Recurring purchase * New customer purchase * First recurring purchase (sent as the standard Subscribe event on newer connections) * Post purchase upsell We ordered them just like in the screenshot above, and we're going to use them for calculating eye-opening metrics that help advertisers understand what REALLY performs (and what doesn't!) in Meta. In order to use these in calculated metrics, you need to [register these events as custom conversions](/integrations/facebook-capi/meta-ads-custom-events-verifying-new-and-returning-customer-purchase.md#measuring-new-andor-returning-customer-purchases-in-meta-ads-reports). ![](https://3956158252-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1QhTbrMraNWciQeDvu1b%2Fuploads%2Fgit-blob-700754af6ef5f79d67b0ffdf97f382b0f1213666%2Fcustom-conversions-list.png?alt=media) That step is necessary because the Littledata custom events are not standard in Meta and there are no accompanying metrics for them (e.g just like we have out-of-the-box metric "Purchases'). After registering them you'll be able to see them as column in ANY campaign, ad set or ad, just like this: ![](https://3956158252-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1QhTbrMraNWciQeDvu1b%2Fuploads%2Fgit-blob-2620faa296c9a6933481becb7a41717c4f3a6504%2Fnew-customer-purchases-per-ad-set.png?alt=media) In the example above we can see how many new customers are coming from each ad set, and you think it looks cool, right? Wait till we show you the actual calculated metric which everyone understand (C-suite especially!) Customer acquisition cost! ![](https://3956158252-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1QhTbrMraNWciQeDvu1b%2Fuploads%2Fgit-blob-d2f05b5562ac7de40c0cb0485971a13f6275ab20%2Fcac-formula.png?alt=media) Now given that you're a doer and not only a reader you'll go ahead right now and replicate the steps explained, and if you do you'll be able to surface a report like this and finally give your ads a fair comparison: ![](https://3956158252-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1QhTbrMraNWciQeDvu1b%2Fuploads%2Fgit-blob-196f351b916440ccb44ac38f578f5d8c0adf13f2%2Fcac-in-reports-and-nc-value.png?alt=media) Kaboom! Now you can see what price do you pay for new customers for each ad set! (Can be applied to campaigns and ads as well) If you're confused with the front\¢er column for new-customer purchases Conversion value - it's available by default based on the real value of the proper purchase events. ## New Customer Index How many new customer purchases you get for each returning customer purchase. Formula: New customer index = new customer purchases ÷ returning customer purchases (format: Percentage) ![](https://3956158252-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1QhTbrMraNWciQeDvu1b%2Fuploads%2Fgit-blob-2474d8036ec2bb5480f10a98cd9866ea6ff4935d%2Fnew-customer-index.png?alt=media) A returning customer can buy many times, so this is an index, not an exact new vs returning rate. ![](https://3956158252-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F1QhTbrMraNWciQeDvu1b%2Fuploads%2Fgit-blob-dc3af58b320a210c0a990dc826056514217db51c%2Fnci-in-action.png?alt=media) Use it to check campaigns meant to grow your brand. A campaign can show a high ROAS, but if most buyers were returning customers, it isn't bringing in many new ones. It also shows whether a creative works with cold audiences or only with people who already know your brand. ## Subscription CVR How often a click leads to a new subscription. Register `First Recurring Purchase - Littledata` as a custom conversion first. Formula: Subscription CVR = first recurring purchases ÷ Link clicks (format: Percentage) You can also try **Landing page views** instead of clicks. The two can differ a lot because of slow page loads or ad blockers. {% hint style="info" %} **Geeks-only DIY** To measure that gap, create a metric that divides **Landing page views** by **Link clicks**. Use link clicks, not all clicks. {% endhint %} ## Subscription Retention *This metric is applicable ONLY for long-standing "evergreen" campaigns that promote subscription products.* The formula is: SR = recurring-orders / first-subscription-orders It will help you understand which asset produces long term success and which low value customers. {% hint style="warning" %} **Do you understand Meta attribution?** This metric should be used with caution as [Meta attribution](/integrations/facebook-capi/why-is-meta-attribution-different-from-ga4.md) i.e the way the platform awards conversion credit can **strongly** affect numbers. {% endhint %} ## Upsell Rate Littledata CAPI connector is designed with one thing in mind: to help ecommerce advertisers pull the most out of their dataset. That's why we made sure to "notify" Meta each time an upsell has happened. Comparing that number against All purchases (or even more specifically new- or returning-customer purchases) can help you better understand how each campaign performs when it comes to upsells! Uspell rate = upsells-littledata ÷ Total Purchases ## Conclusion Relying on out-of-the-box reporting often obscures true profitability, masking whether you are fueling actual growth or simply recycling existing customers. By leveraging Littledata’s granular events to calculate metrics like CAC or Subscription CVR, you help Ads optimize for genuine value instead of vanity metrics (like clicks or impressions). ### Related articles * [New and returning customer purchases in Meta Ads](https://help.littledata.io/integrations/facebook-capi/meta-ads-custom-events-verifying-new-and-returning-customer-purchase) * [How to track subscription purchases in Meta Ads](https://help.littledata.io/integrations/facebook-capi/how-to-track-subscription-purchases-in-meta-ads) * [Recipes](https://help.littledata.io/event-editor/recipes) * [GA4 calculated metrics](https://help.littledata.io/google-analytics/behavior/ga4-calculated-metrics-that-improve-understanding-of-ecommerce-performance)