diff --git a/tsdb/hashcache/series_hash_cache.go b/tsdb/hashcache/series_hash_cache.go
index 964b057301..6680251a6c 100644
--- a/tsdb/hashcache/series_hash_cache.go
+++ b/tsdb/hashcache/series_hash_cache.go
@@ -13,7 +13,7 @@ const (
 
 	// approxBytesPerEntry is the estimated memory footprint (in bytes) of 1 cache
 	// entry, measured with TestSeriesHashCache_MeasureApproximateSizePerEntry().
-	approxBytesPerEntry = 28
+	approxBytesPerEntry = 50
 )
 
 // SeriesHashCache is a bounded cache mapping the per-block series ID with
diff --git a/tsdb/hashcache/series_hash_cache_test.go b/tsdb/hashcache/series_hash_cache_test.go
index 375c8054d7..7c7d7c0758 100644
--- a/tsdb/hashcache/series_hash_cache_test.go
+++ b/tsdb/hashcache/series_hash_cache_test.go
@@ -66,7 +66,7 @@ func TestSeriesHashCache_MeasureApproximateSizePerEntry(t *testing.T) {
 	runtime.ReadMemStats(&after)
 
 	t.Logf("approximate size per entry: %d bytes", (after.TotalAlloc-before.TotalAlloc)/numEntries)
-	require.Equal(t, uint64(approxBytesPerEntry), (after.TotalAlloc-before.TotalAlloc)/numEntries, "approxBytesPerEntry constant is out date")
+	require.Equal(t, approxBytesPerEntry, int((after.TotalAlloc-before.TotalAlloc)/numEntries), "approxBytesPerEntry constant is out date")
 }
 
 func TestSeriesHashCache_Concurrency(t *testing.T) {