> ## 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.
# Custom event value & formulas in Upstack
> Override the value sent with a custom event — send profit, margin, a fixed amount, or a custom formula so ad platforms optimize on the value that matters to you.
By default, Upstack forwards the event's own value to your destinations. You can **override** it so your ad platforms optimize on the value that matters to you — profit instead of revenue, a fixed lead value, or a number you compute yourself. This is the foundation of value‑based bidding.
You set this while creating or editing a mapping (see [Global event mappings](/guides/custom-events/global-event-mappings) and [Destination event mappings](/guides/custom-events/destination-event-mappings)). Turn on **Override event value**, then choose under **Set value to**.
## Value options
| Option | What it sends | Requirements |
| --------------------------- | ----------------------------------------------------------- | ------------------------------------ |
| **Event value** | The value already on the event (the default — no override). | — |
| **Net Revenue** | Revenue after discounts and refunds. | Shopify order data · purchase events |
| **CM1 (Gross Margin)** | Net revenue minus product cost (COGS). | Shopify order data · purchase events |
| **CM2 (After Fulfillment)** | CM1 minus shipping, handling, and fees. | Shopify order data · purchase events |
| **Fixed value** | A set amount you choose (e.g. a flat lead value). | — |
| **Custom formula** | A value you build yourself. | See below |
The revenue and profit presets are computed per order from your [cost settings](/get-started/cost-settings). They require Shopify order data and apply to purchase events. Value‑bearing events like `add_to_cart` can use **Net Revenue** (revenue only — no cost).
Cost- and revenue-based options need Shopify order data. On non‑Shopify accounts you can still use **Fixed value** or a **Custom formula** over your own `data.*` fields.
## Custom formula
The formula builder has two modes:
* **Simple builder** — start with a value, then adjust it step by step (e.g. **Event value × 0.7**). Each part is a **Metric** (a known measure), a **Field** (a custom event field, entered as `data.fieldName`), or a **Number**. Steps apply left to right, like a calculator.
* **Advanced** — write the raw formula directly, with autocomplete for variables. Use `+ − * /` and parentheses.
### Operands you can reference
| Operand | Meaning | Available on |
| ------------------------------------------------------------------------------------------------- | ------------------------------------------------------ | ---------------- |
| `data.value` | The value already on the event. | Every event |
| `data.` | Any custom field on the event (e.g. `data.leadValue`). | Every event |
| `orders.gross_revenue` | Gross revenue before discounts and refunds. | Shopify purchase |
| `orders.net_revenue` | Revenue after discounts and refunds. | Shopify purchase |
| `orders.subtotal`, `orders.tax`, `orders.discount_amount`, `orders.refund_amount`, `orders.units` | Order revenue components. | Shopify purchase |
| `orders.cogs`, `orders.other_cogs` | Cost of goods sold. | Shopify purchase |
| `orders.shipping_cost`, `orders.handling_cost`, `orders.other_fulfillment_cost` | Fulfillment costs. | Shopify purchase |
| `orders.gateway_cost`, `orders.other_transaction_cost` | Transaction/gateway fees. | Shopify purchase |
Cost operands (`orders.cogs`, `orders.shipping_cost`, …) are only available on purchase events, where full order cost data exists.
### Examples
| Goal | Formula |
| ---------------------------------------- | ---------------------------------- |
| Send 70% of the event value | `data.value * 0.7` |
| Send profit (revenue minus product cost) | `orders.net_revenue - orders.cogs` |
| Subtract a flat fee from the value | `data.value - 15` |
| Scale a custom lead value | `data.leadValue * 0.4` |
**A missing field skips the formula — it doesn't zero your value.** If an event doesn't carry a field your formula references (say `data.leadValue` on an event that didn't send it), Upstack skips the override and forwards the event's own value instead, so a missing field never overwrites a real value with `0`. A field that *is* present but genuinely `0` is used as `0`. Still, reference only fields your events reliably send, so the formula applies when you expect it to.
## Related
Create a mapping once and send it to every destination.
Configure the costs behind Net Revenue, CM1, and CM2.
What custom events are and when to use them.
Approve and verify custom events in Meta Events Manager.