diff --git a/tcl/CmdUtil.tcl b/tcl/CmdUtil.tcl
index d6b44ef3..a2380ace 100644
--- a/tcl/CmdUtil.tcl
+++ b/tcl/CmdUtil.tcl
@@ -130,9 +130,9 @@ proc write_units_json { jsonfile } {
   set f [open $jsonfile w]
   puts $f "{"
   foreach unit {"time" "capacitance" "resistance" "voltage" "current" "power"} {
-    puts $f "  \"$unit\": \"[unit_scaled_suffix $unit]\","
+    puts $f "  \"$unit\": \"[unit_scale_suffix $unit]\","
   }
-  puts $f "  \"distance\": \"[unit_scaled_suffix distance]\""
+  puts $f "  \"distance\": \"[unit_scale_suffix distance]\""
   puts $f "}"
   close $f
 }