diff --git a/include/sta/Units.hh b/include/sta/Units.hh
index a33f9f0f..8b54be5f 100644
--- a/include/sta/Units.hh
+++ b/include/sta/Units.hh
@@ -42,10 +42,15 @@ public:
   void operator=(const Unit &unit);
   float scale() const { return scale_; }
   void setScale(float scale);
+  // Mkmunpf abbreviation for scale.
   std::string scaleAbbreviation() const;
-  const char *suffix() const { return suffix_.c_str(); }
+  // 1Mkmunpf or scale
+  std::string scaleString() const;
+  std::string suffix() const { return suffix_; }
+  // scaleString + suffix
+  std::string scaleSuffix() const;
   // scale abbreviation + suffix
-  const char *scaledSuffix() const { return scaled_suffix_.c_str(); }
+  std::string scaleAbbrevSuffix() const { return scale_abbrev_suffix_; }
   void setSuffix(const char *suffix);
   int digits() const { return digits_; }
   void setDigits(int digits);
@@ -57,11 +62,11 @@ public:
 		       int digits) const;
 
 private:
-  void setScaledSuffix();
+  void setScaleAbbrevSuffix();
 
   float scale_;			// multiplier from user units to internal units
   std::string suffix_;		// print suffix
-  std::string scaled_suffix_;
+  std::string scale_abbrev_suffix_;
   int digits_;			// print digits (after decimal pt)
 };
 
diff --git a/liberty/LibertyWriter.cc b/liberty/LibertyWriter.cc
index 10cce09b..2c4dd1a7 100644
--- a/liberty/LibertyWriter.cc
+++ b/liberty/LibertyWriter.cc
@@ -137,20 +137,20 @@ LibertyWriter::writeHeader()
   fprintf(stream_, "  simulation                     : false;\n");
   const Unit *cap_unit = library_->units()->capacitanceUnit();
   fprintf(stream_, "  capacitive_load_unit (1,%s);\n",
-          cap_unit->scaledSuffix());
+          cap_unit->scaleAbbrevSuffix().c_str());
   fprintf(stream_, "  leakage_power_unit             : 1pW;\n");
   const Unit *current_unit = library_->units()->currentUnit();
   fprintf(stream_, "  current_unit                   : \"1%s\";\n",
-          current_unit->scaledSuffix());
+          current_unit->scaleAbbrevSuffix().c_str());
   const Unit *res_unit = library_->units()->resistanceUnit();
   fprintf(stream_, "  pulling_resistance_unit        : \"1%s\";\n",
-          res_unit->scaledSuffix());
+          res_unit->scaleAbbrevSuffix().c_str());
   const Unit *time_unit = library_->units()->timeUnit();
   fprintf(stream_, "  time_unit                      : \"1%s\";\n",
-          time_unit->scaledSuffix());
+          time_unit->scaleAbbrevSuffix().c_str());
   const Unit *volt_unit = library_->units()->voltageUnit();
   fprintf(stream_, "  voltage_unit                   : \"1%s\";\n",
-          volt_unit->scaledSuffix());
+          volt_unit->scaleAbbrevSuffix().c_str());
   fprintf(stream_, "  library_features(report_delay_calculation);\n");
   fprintf(stream_, "\n");
 
diff --git a/liberty/Units.cc b/liberty/Units.cc
index 6358de31..8dcbb4f0 100644
--- a/liberty/Units.cc
+++ b/liberty/Units.cc
@@ -40,7 +40,7 @@ Unit::Unit(const char *suffix) :
   suffix_(suffix),
   digits_(3)
 {
-  setScaledSuffix();
+  setScaleAbbrevSuffix();
 }
 
 Unit::Unit(float scale,
@@ -50,13 +50,13 @@ Unit::Unit(float scale,
   suffix_(suffix),
   digits_(digits)
 {
-  setScaledSuffix();
+  setScaleAbbrevSuffix();
 }
 
 void
-Unit::setScaledSuffix()
+Unit::setScaleAbbrevSuffix()
 {
-  scaled_suffix_ = scaleAbbreviation() + suffix_;
+  scale_abbrev_suffix_ = scaleAbbreviation() + suffix_;
 }
 
 void
@@ -64,7 +64,7 @@ Unit::operator=(const Unit &unit)
 {
   scale_ = unit.scale_;
   suffix_ = unit.suffix_;
-  scaled_suffix_ = unit.scaled_suffix_;
+  scale_abbrev_suffix_ = unit.scale_abbrev_suffix_;
   digits_ = unit.digits_;
 }
 
@@ -84,11 +84,34 @@ void
 Unit::setScale(float scale)
 {
   scale_ = scale;
-  setScaledSuffix();
+  setScaleAbbrevSuffix();
 }
 
 std::string
 Unit::scaleAbbreviation() const
+{
+  if (fuzzyEqual(scale_, 1E+6))
+    return "M";
+  else if (fuzzyEqual(scale_, 1E+3))
+    return "k";
+  if (fuzzyEqual(scale_, 1.0))
+    return "";
+  else if (fuzzyEqual(scale_, 1E-3))
+    return "m";
+  else if (fuzzyEqual(scale_, 1E-6))
+    return "u";
+  else if (fuzzyEqual(scale_, 1E-9))
+    return "n";
+  else if (fuzzyEqual(scale_, 1E-12))
+    return "p";
+  else if (fuzzyEqual(scale_, 1E-15))
+    return "f";
+  else
+    return "?";
+}
+
+std::string
+Unit::scaleString() const
 {
   if (fuzzyEqual(scale_, 1E+6))
     return "1M";
@@ -110,11 +133,17 @@ Unit::scaleAbbreviation() const
     return stdstrPrint("%.1e", scale_);
 }
 
+std::string
+Unit::scaleSuffix() const
+{
+  return scaleString() + suffix_;
+}
+
 void
 Unit::setSuffix(const char *suffix)
 {
   suffix_ = suffix;
-  setScaledSuffix();
+  setScaleAbbrevSuffix();
 }
 
 void
diff --git a/tcl/CmdUtil.tcl b/tcl/CmdUtil.tcl
index 17a9b75c..d6b44ef3 100644
--- a/tcl/CmdUtil.tcl
+++ b/tcl/CmdUtil.tcl
@@ -122,7 +122,7 @@ define_cmd_args "report_units" {}
 proc report_units { args } {
   check_argc_eq0 "report_units" $args
   foreach unit {"time" "capacitance" "resistance" "voltage" "current" "power" "distance"} {
-    report_line " $unit [unit_scaled_suffix $unit]"
+    report_line " $unit [unit_scale_suffix $unit]"
   }
 }
 
diff --git a/util/Util.i b/util/Util.i
index 6b89c89b..6c7ec10f 100644
--- a/util/Util.i
+++ b/util/Util.i
@@ -23,6 +23,7 @@
 // This notice may not be removed or altered from any source distribution.
 
 %module util
+%include <std_string.i>
 
 %{
 
@@ -425,7 +426,7 @@ unit_scale_abbreviation (const char *unit_name)
     return "";
 }
 
-const char *
+std::string
 unit_suffix(const char *unit_name)
 {
   Unit *unit = Sta::sta()->units()->find(unit_name);
@@ -435,12 +436,23 @@ unit_suffix(const char *unit_name)
     return "";
 }
 
-const char *
-unit_scaled_suffix(const char *unit_name)
+std::string
+unit_scale_suffix(const char *unit_name)
+{
+  Unit *unit = Sta::sta()->units()->find(unit_name);
+  if (unit) {
+    return unit->scaleSuffix();
+  }
+  else
+    return "";
+}
+
+std::string
+unit_scale_abbrev_suffix(const char *unit_name)
 {
   Unit *unit = Sta::sta()->units()->find(unit_name);
   if (unit)
-    return unit->scaledSuffix();
+    return unit->scaleAbbrevSuffix();
   else
     return "";
 }