diff --git a/pkg/compactor/sharded_block_populator.go b/pkg/compactor/sharded_block_populator.go
index 3a3e72e33f..a8d4228d13 100644
--- a/pkg/compactor/sharded_block_populator.go
+++ b/pkg/compactor/sharded_block_populator.go
@@ -177,7 +177,16 @@ func (c ShardedBlockPopulator) PopulateBlock(ctx context.Context, metrics *tsdb.
 				meta.Stats.NumChunks += uint64(len(chks))
 				meta.Stats.NumSeries++
 				for _, chk := range chks {
-					meta.Stats.NumSamples += uint64(chk.Chunk.NumSamples())
+					samples := uint64(chk.Chunk.NumSamples())
+					meta.Stats.NumSamples += samples
+					switch chk.Chunk.Encoding() {
+					case chunkenc.EncHistogram, chunkenc.EncFloatHistogram:
+						meta.Stats.NumHistogramSamples += samples
+					case chunkenc.EncXOR:
+						meta.Stats.NumFloatSamples += samples
+					default:
+						return errors.Wrapf(err, "unknown chunk encoding %s", chk.Chunk.Encoding().String())
+					}
 				}
 
 				for _, chk := range chks {