diff --git a/ch11_blockchain.adoc b/ch11_blockchain.adoc
index 8ff7cd97..15d3c94b 100644
--- a/ch11_blockchain.adoc
+++ b/ch11_blockchain.adoc
@@ -527,7 +527,7 @@ The largest possible block can hold almost 16,000 transactions in 4,000,000
 bytes, but proving any particular one of those 16,000 transactions
 is a part of that block only requires a copy of the transaction, a copy
 of the 80-byte block header, and 448 bytes for the merkle proof.  That
-makes the largest possible proof almost 10,000 times smaller than the
+makes the largest possible proof almost 5,000 times smaller than the
 largest possible Bitcoin block.
 
 === Merkle Trees and Lightweight Clients