diff --git a/command/build.go b/command/build.go
index ecbccc35b..794c5a775 100644
--- a/command/build.go
+++ b/command/build.go
@@ -309,7 +309,7 @@ Options:
   -machine-readable             Machine-readable output
   -on-error=[cleanup|abort|ask] If the build fails do: clean up (default), abort, or ask
   -parallel=false               Disable parallelization (on by default)
-  -timestamp=true               Enable timestamps in build log (off by default)
+  -timestamp-ui=true            Prefix each ui output with an RFC3339 timestamp (off by default).
   -var 'key=value'              Variable for templates, can be used multiple times.
   -var-file=path                JSON file containing user variables.
 `
diff --git a/packer/ui.go b/packer/ui.go
index 9e46d46b8..2a0f5e275 100644
--- a/packer/ui.go
+++ b/packer/ui.go
@@ -99,14 +99,6 @@ type MachineReadableUi struct {
 
 var _ Ui = new(MachineReadableUi)
 
-// TimestampedUi is a UI that wraps another UI implementation and prefixes
-// prefixes each message with an RFC3339 timestamp
-type TimestampedUi struct {
-	Ui Ui
-}
-
-var _ Ui = new(TimestampedUi)
-
 func (u *ColoredUi) Ask(query string) (string, error) {
 	return u.Ui.Ask(u.colorize(query, u.Color, true))
 }
@@ -351,6 +343,14 @@ func (u *MachineReadableUi) ProgressBar() ProgressBar {
 	return new(NoopProgressBar)
 }
 
+// TimestampedUi is a UI that wraps another UI implementation and prefixes
+// prefixes each message with an RFC3339 timestamp
+type TimestampedUi struct {
+	Ui Ui
+}
+
+var _ Ui = new(TimestampedUi)
+
 func (u *TimestampedUi) Ask(query string) (string, error) {
 	return u.Ui.Ask(query)
 }
diff --git a/website/source/docs/commands/build.html.md b/website/source/docs/commands/build.html.md
index 433419390..1c44df43c 100644
--- a/website/source/docs/commands/build.html.md
+++ b/website/source/docs/commands/build.html.md
@@ -50,8 +50,8 @@ that are created will be outputted at the end of the build.
 -   `-parallel=false` - Disable parallelization of multiple builders (on by
     default).
 
--   `-timestamp=true` - Enable timestamps for build logs without adding the extra
-    information included if PACKER_LOG is true.
+-   `-timestamp-ui=true` - Prefix each ui output with an RFC3339 timestamp (off
+    by default).
 
 -   `-var` - Set a variable in your packer template. This option can be used
     multiple times. This is useful for setting version numbers for your build.