diff --git a/doc/man/taskrc.5.in b/doc/man/taskrc.5.in
index edcd7997c..21d52e30a 100644
--- a/doc/man/taskrc.5.in
+++ b/doc/man/taskrc.5.in
@@ -362,9 +362,9 @@ Enables or disables pattern support on the command line, such as /foo/.
 Defaults to on.
 
 .TP
-.B expressions=on
-Enables or disables algebraic expression support on the command line, such as
-"due<eom and (pri=H or pri=M)".  Defaults to on.
+.B expressions=infix|postfix
+Sets a preference for infix expressions (1 + 2) or postfix expressions (1 2 +).
+Defaults to infix.
 
 .TP
 .B dom=on
diff --git a/src/Config.cpp b/src/Config.cpp
index a32400c67..df2d9eaa7 100644
--- a/src/Config.cpp
+++ b/src/Config.cpp
@@ -98,7 +98,7 @@ std::string Config::_defaults =
   "burndown.bias=0.666                            # Weighted mean bias toward recent data\n"
   "regex=no                                       # Assume all search/filter strings are regexes\n"
   "xterm.title=no                                 # Sets xterm title for some commands\n"
-  "expressions=on                                 # Support for algebraic expressions\n"
+  "expressions=infix                              # Prefer infix over postfix expressions\n"
   "patterns=on                                    # Support for regex patterns\n"
   "dom=on                                         # Support DOM access\n"
   "json.array=off                                 # Enclose JSON output in [ ]\n"
diff --git a/src/args.cpp b/src/args.cpp
index a4e9e5669..9f480f5df 100644
--- a/src/args.cpp
+++ b/src/args.cpp
@@ -126,6 +126,7 @@ int main (int argc, const char** argv)
     a3t.entity ("operator",   ">=");
     a3t.entity ("operator",   "!~");
     a3t.entity ("operator",   "!=");
+    a3t.entity ("operator",   "==");
     a3t.entity ("operator",   "=");
     a3t.entity ("operator",   ">");
     a3t.entity ("operator",   "~");
@@ -140,6 +141,9 @@ int main (int argc, const char** argv)
     a3t.entity ("operator",   "<");
     a3t.entity ("operator",   "(");
     a3t.entity ("operator",   ")");
+    a3t.entity ("operator",   "%");
+    a3t.entity ("operator",   "^");
+    a3t.entity ("operator",   "!");
 
     Tree* tree = a3t.parse ();
     if (tree)
diff --git a/src/commands/CmdCalc.cpp b/src/commands/CmdCalc.cpp
index 2786a9d13..0f061a7c7 100644
--- a/src/commands/CmdCalc.cpp
+++ b/src/commands/CmdCalc.cpp
@@ -26,12 +26,28 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 #include <Context.h>
+#include <Eval.h>
+#include <Dates.h>
 #include <main.h>
 #include <i18n.h>
 #include <CmdCalc.h>
 
 extern Context context;
 
+////////////////////////////////////////////////////////////////////////////////
+static bool domSource (const std::string& name, Variant& value)
+{
+  Task t;
+  std::string resolved = context.dom.get (name, t);
+  if (resolved != name)
+  {
+    value = Variant (resolved);
+    return true;
+  }
+
+  return false;
+}
+
 ////////////////////////////////////////////////////////////////////////////////
 CmdCalc::CmdCalc ()
 {
@@ -45,12 +61,35 @@ CmdCalc::CmdCalc ()
 ////////////////////////////////////////////////////////////////////////////////
 int CmdCalc::execute (std::string& output)
 {
-  int rc = 0;
+  // Configurable infix/postfix
+  bool infix = true;
+  if (context.config.get ("expressions") == "infix")
+    infix = true;
+  else if (context.config.get ("expressions") == "postfix")
+    infix = false;
 
-  // TODO Configurable infix/postfix
-  // TODO Configurable date/number precedence
+  // Create an evaluator with DOM access.
+  Eval e;
+  e.addSource (namedDates);
+  e.addSource (domSource);
+  e.ambiguity (false);  // TODO Could/should be configurable.
 
-  return rc;
+  // Compile all the args into one expression.
+  std::string expression;
+  std::vector <std::string> words = context.a3.extract_words ();
+  std::vector <std::string>::iterator word;
+  for (word = words.begin (); word != words.end (); ++word)
+    expression += *word + " ";
+
+  // Evaluate according to preference.
+  Variant result;
+  if (infix)
+    e.evaluateInfixExpression (expression, result);
+  else
+    e.evaluatePostfixExpression (expression, result);
+
+  output = (std::string) result + "\n";
+  return 0;
 }
 
 ////////////////////////////////////////////////////////////////////////////////