diff --git a/README.md b/README.md
index d9b7d88..d2f03a4 100644
--- a/README.md
+++ b/README.md
@@ -106,6 +106,8 @@ const sms = await textbee.getSms(deviceId, smsId)
 const { batch, messages } = await textbee.getSmsBatch(deviceId, smsBatchId)
 ```
 
+`batch.status` and the batch counts come from the messages in the batch, so they change as each message reports. `successCount` counts messages sent or delivered, and `failureCount` counts failed ones. `pendingCount`, `dispatchedCount`, `sentCount`, `deliveredCount` and `unknownCount` break the rest down by state.
+
 ## Verifying webhooks
 
 textbee signs each webhook delivery with HMAC-SHA256 and sends the hex digest in the `X-Signature` header. Pass the raw request body, not a re-serialized object, whenever your framework gives you access to it.
diff --git a/src/types.ts b/src/types.ts
index 5ab2c5f..264c024 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -187,13 +187,29 @@ export interface Message {
   updatedAt?: string
 }
 
+/**
+ * A send batch. The status and counts are calculated from the batch's
+ * messages, so they change as each message reports.
+ */
 export interface SmsBatch {
   _id: string
   message: string
   recipientCount: number
   recipientPreview?: string
+  /** Messages sent or delivered: `sentCount + deliveredCount`. */
   successCount: number
+  /** Messages that failed. */
   failureCount: number
+  /** Messages not yet handed to the phone. */
+  pendingCount?: number
+  /** Messages handed to the phone with no result yet. */
+  dispatchedCount?: number
+  /** Messages sent with no delivery report yet. */
+  sentCount?: number
+  /** Messages with a delivery report. */
+  deliveredCount?: number
+  /** Messages with no report from the phone within 20 minutes. */
+  unknownCount?: number
   status:
     | 'pending'
     | 'processing'
@@ -202,7 +218,10 @@ export interface SmsBatch {
     | 'failed'
     | 'unknown'
   error?: string
+  /** When the batch reached its current final status. Absent while processing. */
   completedAt?: string
+  /** When the status and counts were last calculated. */
+  statusCheckedAt?: string
   createdAt?: string
   updatedAt?: string
 }