diff --git a/src/main/java/com/google/devtools/build/lib/remote/ByteStreamUploader.java b/src/main/java/com/google/devtools/build/lib/remote/ByteStreamUploader.java
index c010f9c75ae75c..40ec95b7cddcce 100644
--- a/src/main/java/com/google/devtools/build/lib/remote/ByteStreamUploader.java
+++ b/src/main/java/com/google/devtools/build/lib/remote/ByteStreamUploader.java
@@ -408,8 +408,9 @@ ListenableFuture<Void> start() {
               () ->
                   retrier.executeAsync(
                       () -> {
-                        if (chunker.bytesLeft() != 0
-                            || committedOffset.get() < chunker.getActualSize()) {
+                        long offset = committedOffset.get();
+                        if ((offset == 0 && chunker.bytesLeft() != 0)
+                            || (offset < chunker.getActualSize())) {
                           return callAndQueryOnFailure(committedOffset, progressiveBackoff);
                         }
                         return Futures.immediateFuture(null);
diff --git a/src/main/java/com/google/devtools/build/lib/remote/Chunker.java b/src/main/java/com/google/devtools/build/lib/remote/Chunker.java
index 38a96f44e51031..c778346f766182 100644
--- a/src/main/java/com/google/devtools/build/lib/remote/Chunker.java
+++ b/src/main/java/com/google/devtools/build/lib/remote/Chunker.java
@@ -118,7 +118,8 @@ public int hashCode() {
   // lazily on the first call to next(), as opposed to opening it in the constructor or on reset().
   private boolean initialized;
 
-  private AtomicLong actualSize = new AtomicLong(0);
+  private AtomicLong processedBytes = new AtomicLong(0);
+  private long actualSize = -1;
 
   Chunker(Supplier<InputStream> dataSupplier, long size, int chunkSize, boolean compressed) {
     this.dataSupplier = checkNotNull(dataSupplier);
@@ -136,11 +137,25 @@ public long getSize() {
     return size;
   }
 
-  public long getActualSize() {
-    long actualSize = this.actualSize.get();
-    checkState(bytesLeft() == 0);
-    checkState(compressed || actualSize == size);
-    return actualSize;
+  public long getActualSize() throws IOException {
+    if (compressed) {
+      if (actualSize == -1) {
+        if (bytesLeft() != 0) {
+          // If there are bytes left, compute the remaining size
+          long currentOffset = offset;
+          while (hasNext()) {
+            next();
+          }
+          actualSize = processedBytes.get();
+          seek(currentOffset);
+        } else {
+          actualSize = processedBytes.get();
+        }
+      }
+      return actualSize;
+    } else {
+      return size;
+    }
   }
 
   /**
@@ -198,12 +213,12 @@ public void seek(long toOffset) throws IOException {
         if (remaining == 0 && toOffset == size) {
           zos.close();
         }
-        actualSize.addAndGet(baos.toByteArray().length);
+        processedBytes.addAndGet(baos.toByteArray().length);
         baos.reset();
       }
     } else {
       ByteStreams.skipFully(data, toOffset - offset);
-      actualSize.addAndGet(toOffset);
+      processedBytes.addAndGet(toOffset);
     }
     offset = toOffset;
   }
@@ -273,7 +288,7 @@ public Chunk next() throws IOException {
     } else {
       blob = ByteString.copyFrom(chunkCache, 0, bytesToRead);
     }
-    actualSize.addAndGet(blob.size());
+    processedBytes.addAndGet(blob.size());
 
     // This has to happen after actualSize has been updated
     // or the guard in getActualSize won't work.
@@ -310,7 +325,7 @@ private void maybeInitialize() throws IOException {
       baos = new ByteArrayOutputStream();
       zos = new ZstdOutputStream(baos);
     }
-    actualSize = new AtomicLong(0);
+    processedBytes = new AtomicLong(0);
     initialized = true;
   }
 
diff --git a/src/test/java/com/google/devtools/build/lib/remote/ChunkerTest.java b/src/test/java/com/google/devtools/build/lib/remote/ChunkerTest.java
index ce1575948b57b8..ab9ada190cae67 100644
--- a/src/test/java/com/google/devtools/build/lib/remote/ChunkerTest.java
+++ b/src/test/java/com/google/devtools/build/lib/remote/ChunkerTest.java
@@ -201,23 +201,6 @@ public void testMultiChunkCompressed() throws IOException {
     assertThat(Zstd.decompress(baos.toByteArray(), data.length)).isEqualTo(data);
   }
 
-  @Test
-  public void testActualSizeThrowsIfCalledEarly() throws IOException {
-    byte[] data = {72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33};
-    Chunker chunker = Chunker.builder().setInput(data).setChunkSize(data.length / 2).build();
-    chunker.next();
-    assertThrows(IllegalStateException.class, chunker::getActualSize);
-  }
-
-  @Test
-  public void testActualSizeIsSizeForUncompressedBlob() throws IOException {
-    byte[] data = {72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33};
-    Chunker chunker = Chunker.builder().setInput(data).setChunkSize(data.length * 2).build();
-    chunker.next();
-    assertThat(chunker.hasNext()).isFalse();
-    assertThat(chunker.getActualSize()).isEqualTo(chunker.getSize());
-  }
-
   @Test
   public void testActualSizeIsCorrectAfterSeek() throws IOException {
     byte[] data = {72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33};