Update pricing.mdx (#24048)

* Update pricing.mdx

better explain concurrency calc

* Wording upate and detail formatting

---------

Co-authored-by: ToriLindsay <[email protected]>

Author: kathayl

src/content/docs/browser-rendering/platform/pricing.mdx

@@ -4,10 +4,11 @@ title: Pricing
 sidebar:
   order: 31
 ---
+import { Details } from "~/components"
 
 Browser Rendering is currently available at no cost up to the [limits](/browser-rendering/platform/limits/) specified, with billing beginning on August 20, 2025.
 
-There are two ways to use Browser Rendering. Depending on the method you use, here’s how billing will work:
+There are two ways to use Browser Rendering. Depending on the method you use, here is how billing works:
 - [**REST API**](/browser-rendering/rest-api/): Charged for **Duration** only ($/browser hour)
 - [**Workers Bindings**](/browser-rendering/workers-bindings/): Charged for both **Duration** and **Concurrency** ($/browser hour and # of concurrent browsers)
 
@@ -16,7 +17,13 @@ There are two ways to use Browser Rendering. Depending on the method you use, he
 | **Workers Free** | 10 minutes per day | 3 concurrent browsers | N/A |
 | **Workers Paid** | 10 hours per month | 10 concurrent browsers (averaged monthly) | **1. REST API**: $0.09 per additional browser hour <br />**2. Workers Bindings**: $0.09 per additional browser hour <br /> $2.00 per additional concurrent browser |
 
+<Details header="Where can I monitor my usage?">
 You can monitor your Browser Rendering usage in the [Cloudflare dashboard](https://dash.cloudflare.com). Go to **Compute (Workers)** > **Browser Rendering**.
+</Details>
+
+<Details header="How is the number of concurrent browsers calculated?">
+Cloudflare calculates concurrent browsers as the **monthly average of your daily peak usage**. In other words, we record **the peak number of concurrent browsers each day** and then average those values over the month. This approach reflects your typical traffic and ensures you are not disproportionately charged for brief spikes in browser concurrency.
+</Details>
 
 ### Examples of Workers Paid pricing
 <br/>