diff --git a/library/Text/Builder.hs b/library/Text/Builder.hs
--- a/library/Text/Builder.hs
+++ b/library/Text/Builder.hs
@@ -292,7 +292,7 @@
   byDivisor = div n divisor
   byExtraTen = div byDivisor 10
   remainder = byDivisor - byExtraTen * 10
-  in if remainder == 0 || byExtraTen > 10
+  in if remainder == 0 || byExtraTen >= 10
     then thousandSeparatedDecimal separatorChar byExtraTen
     else thousandSeparatedDecimal separatorChar byExtraTen <> "." <> decimalDigit remainder
 
diff --git a/test/Main.hs b/test/Main.hs
--- a/test/Main.hs
+++ b/test/Main.hs
@@ -91,5 +91,6 @@
       assertEqual "" "1.1kB" (B.run (B.dataSizeInBytesInDecimal ',' 1100))
       assertEqual "" "1.1MB" (B.run (B.dataSizeInBytesInDecimal ',' 1150000))
       assertEqual "" "9.9MB" (B.run (B.dataSizeInBytesInDecimal ',' 9990000))
+      assertEqual "" "10MB" (B.run (B.dataSizeInBytesInDecimal ',' 10100000))
       assertEqual "" "1,000YB" (B.run (B.dataSizeInBytesInDecimal ',' 1000000000000000000000000000))
   ]
diff --git a/text-builder.cabal b/text-builder.cabal
--- a/text-builder.cabal
+++ b/text-builder.cabal
@@ -1,5 +1,5 @@
 name: text-builder
-version: 0.6.6
+version: 0.6.6.1
 category: Text
 synopsis: An efficient strict text builder
 homepage: https://github.com/nikita-volkov/text-builder