diff --git a/crates/queryd/src/delta.rs b/crates/queryd/src/delta.rs
index 30dcc4a..af5ccc8 100644
--- a/crates/queryd/src/delta.rs
+++ b/crates/queryd/src/delta.rs
@@ -84,14 +84,17 @@ pub async fn compact(
     // Load deltas
     let delta_batches = load_deltas(store, dataset_name).await?;
     let delta_count = delta_batches.len();
+    // Row counts captured before extend; previously base_rows subtracted delta_count (files) from rows — unit mismatch.
+    let base_row_count: usize = base_batches.iter().map(|b| b.num_rows()).sum();
+    let delta_row_count: usize = delta_batches.iter().map(|b| b.num_rows()).sum();
 
     let has_tombstones = !tombstones.is_empty();
     let nothing_to_do = delta_batches.is_empty() && !has_tombstones;
     if nothing_to_do {
         return Ok(CompactResult {
-            base_rows: base_batches.iter().map(|b| b.num_rows()).sum(),
+            base_rows: base_row_count,
             delta_rows: 0,
-            final_rows: base_batches.iter().map(|b| b.num_rows()).sum(),
+            final_rows: base_row_count,
             deltas_merged: 0,
             tombstones_applied: 0,
             rows_dropped_by_tombstones: 0,
@@ -99,7 +102,7 @@ pub async fn compact(
     }
 
     base_batches.extend(delta_batches);
-    let pre_filter_rows: usize = base_batches.iter().map(|b| b.num_rows()).sum();
+    let pre_filter_rows: usize = base_row_count + delta_row_count;
 
     // If primary key specified, deduplicate (keep last occurrence)
     let merged_batches = if let Some(_pk) = primary_key_col {
@@ -183,8 +186,8 @@ pub async fn compact(
     );
 
     Ok(CompactResult {
-        base_rows: pre_filter_rows - delta_count,  // rough base-before-deltas
-        delta_rows: delta_count,
+        base_rows: base_row_count,
+        delta_rows: delta_row_count,
         final_rows,
         deltas_merged: delta_count,
         tombstones_applied: tombstones.len(),