diff --git a/lib/rscons/application.rb b/lib/rscons/application.rb
index 216f5e6..2e6db12 100644
--- a/lib/rscons/application.rb
+++ b/lib/rscons/application.rb
@@ -21,7 +21,7 @@ module Rscons
 
     # Create Application instance.
     def initialize
-      @n_threads = determine_n_threads
+      @n_threads = Util.determine_n_threads
       @vars = VarSet.new
     end
 
@@ -157,39 +157,6 @@ module Rscons
       rv
     end
 
-    # Determine the number of threads to use by default.
-    #
-    # @return [Integer]
-    #   The number of threads to use by default.
-    def determine_n_threads
-      # If the user specifies the number of threads in the environment, then
-      # respect that.
-      if ENV["RSCONS_NTHREADS"] =~ /^(\d+)$/
-        return $1.to_i
-      end
-
-      # Otherwise try to figure out how many threads are available on the
-      # host hardware.
-      begin
-        case RbConfig::CONFIG["host_os"]
-        when /linux/
-          return File.read("/proc/cpuinfo").scan(/^processor\s*:/).size
-        when /mswin|mingw/
-          if `wmic cpu get NumberOfLogicalProcessors /value` =~ /NumberOfLogicalProcessors=(\d+)/
-            return $1.to_i
-          end
-        when /darwin/
-          if `sysctl -n hw.ncpu` =~ /(\d+)/
-            return $1.to_i
-          end
-        end
-      rescue
-      end
-
-      # If we can't figure it out, default to 1.
-      1
-    end
-
   end
 
 end
diff --git a/lib/rscons/util.rb b/lib/rscons/util.rb
index 710e2dc..0c6ba25 100644
--- a/lib/rscons/util.rb
+++ b/lib/rscons/util.rb
@@ -26,6 +26,39 @@ module Rscons
         command.map { |c| c =~ /\s/ ? "'#{c}'" : c }.join(' ')
       end
 
+      # Determine the number of threads to use by default.
+      #
+      # @return [Integer]
+      #   The number of threads to use by default.
+      def determine_n_threads
+        # If the user specifies the number of threads in the environment, then
+        # respect that.
+        if ENV["RSCONS_NTHREADS"] =~ /^(\d+)$/
+          return $1.to_i
+        end
+
+        # Otherwise try to figure out how many threads are available on the
+        # host hardware.
+        begin
+          case RbConfig::CONFIG["host_os"]
+          when /linux/
+            return File.read("/proc/cpuinfo").scan(/^processor\s*:/).size
+          when /mswin|mingw/
+            if `wmic cpu get NumberOfLogicalProcessors /value` =~ /NumberOfLogicalProcessors=(\d+)/
+              return $1.to_i
+            end
+          when /darwin/
+            if `sysctl -n hw.ncpu` =~ /(\d+)/
+              return $1.to_i
+            end
+          end
+        rescue
+        end
+
+        # If we can't figure it out, default to 1.
+        1
+      end
+
       # Return a string showing the path specified, or if more than one, then
       # the first path with a "(+D)" afterward, where D is the number of
       # remaining paths.
diff --git a/spec/rscons/application_spec.rb b/spec/rscons/application_spec.rb
index 6a754ea..05a0f68 100644
--- a/spec/rscons/application_spec.rb
+++ b/spec/rscons/application_spec.rb
@@ -26,71 +26,5 @@ module Rscons
       end
     end
 
-    describe ".determine_n_threads" do
-      context "when specified by environment variable" do
-        before(:each) do
-          expect(ENV).to receive(:[]).with("RSCONS_NTHREADS").and_return("3")
-        end
-        it "returns the user-specified number of threads to use" do
-          expect(Rscons.application.__send__(:determine_n_threads)).to eq(3)
-        end
-      end
-
-      context "when not specified by environment variable" do
-        before(:each) do
-          expect(ENV).to receive(:[]).with("RSCONS_NTHREADS").and_return(nil)
-        end
-
-        context "on Linux" do
-          before(:each) do
-            expect(RbConfig::CONFIG).to receive(:[]).with("host_os").and_return("linux")
-          end
-          it "returns the number of processors from /proc/cpuinfo" do
-            expect(File).to receive(:read).with("/proc/cpuinfo").and_return(<<EOF)
-processor : 0
-processor   : 1
-EOF
-            expect(Rscons.application.__send__(:determine_n_threads)).to eq(2)
-          end
-        end
-
-        context "on Windows" do
-          before(:each) do
-            expect(RbConfig::CONFIG).to receive(:[]).with("host_os").and_return("mingw")
-          end
-          it "returns the number of logical processors that wmic reports" do
-            expect(Rscons.application).to receive(:`).with("wmic cpu get NumberOfLogicalProcessors /value").and_return("NumberOfLogicalProcessors=7")
-            expect(Rscons.application.__send__(:determine_n_threads)).to eq(7)
-          end
-        end
-
-        context "on Darwin" do
-          before(:each) do
-            expect(RbConfig::CONFIG).to receive(:[]).with("host_os").and_return("darwin")
-          end
-          it "returns the number of threads that sysctl reports" do
-            expect(Rscons.application).to receive(:`).with("sysctl -n hw.ncpu").and_return("6")
-            expect(Rscons.application.__send__(:determine_n_threads)).to eq(6)
-          end
-        end
-
-        context "on an unknown platform" do
-          before(:each) do
-            expect(RbConfig::CONFIG).to receive(:[]).with("host_os").and_return("other")
-          end
-          it "returns 1" do
-            expect(Rscons.application.__send__(:determine_n_threads)).to eq(1)
-          end
-        end
-
-        context "when an error occurs" do
-          it "returns 1" do
-            expect(RbConfig::CONFIG).to receive(:[]).with("host_os").and_raise("foo")
-            expect(Rscons.application.__send__(:determine_n_threads)).to eq(1)
-          end
-        end
-      end
-    end
-
   end
 end
diff --git a/spec/rscons/util_spec.rb b/spec/rscons/util_spec.rb
index ba08801..4c39c5e 100644
--- a/spec/rscons/util_spec.rb
+++ b/spec/rscons/util_spec.rb
@@ -29,6 +29,72 @@ module Rscons
       end
     end
 
+    describe ".determine_n_threads" do
+      context "when specified by environment variable" do
+        before(:each) do
+          expect(ENV).to receive(:[]).with("RSCONS_NTHREADS").and_return("3")
+        end
+        it "returns the user-specified number of threads to use" do
+          expect(Util.determine_n_threads).to eq(3)
+        end
+      end
+
+      context "when not specified by environment variable" do
+        before(:each) do
+          expect(ENV).to receive(:[]).with("RSCONS_NTHREADS").and_return(nil)
+        end
+
+        context "on Linux" do
+          before(:each) do
+            expect(RbConfig::CONFIG).to receive(:[]).with("host_os").and_return("linux")
+          end
+          it "returns the number of processors from /proc/cpuinfo" do
+            expect(File).to receive(:read).with("/proc/cpuinfo").and_return(<<EOF)
+processor : 0
+processor   : 1
+EOF
+            expect(Util.determine_n_threads).to eq(2)
+          end
+        end
+
+        context "on Windows" do
+          before(:each) do
+            expect(RbConfig::CONFIG).to receive(:[]).with("host_os").and_return("mingw")
+          end
+          it "returns the number of logical processors that wmic reports" do
+            expect(Util).to receive(:`).with("wmic cpu get NumberOfLogicalProcessors /value").and_return("NumberOfLogicalProcessors=7")
+            expect(Util.determine_n_threads).to eq(7)
+          end
+        end
+
+        context "on Darwin" do
+          before(:each) do
+            expect(RbConfig::CONFIG).to receive(:[]).with("host_os").and_return("darwin")
+          end
+          it "returns the number of threads that sysctl reports" do
+            expect(Util).to receive(:`).with("sysctl -n hw.ncpu").and_return("6")
+            expect(Util.determine_n_threads).to eq(6)
+          end
+        end
+
+        context "on an unknown platform" do
+          before(:each) do
+            expect(RbConfig::CONFIG).to receive(:[]).with("host_os").and_return("other")
+          end
+          it "returns 1" do
+            expect(Util.determine_n_threads).to eq(1)
+          end
+        end
+
+        context "when an error occurs" do
+          it "returns 1" do
+            expect(RbConfig::CONFIG).to receive(:[]).with("host_os").and_raise("foo")
+            expect(Util.determine_n_threads).to eq(1)
+          end
+        end
+      end
+    end
+
     describe ".find_executable" do
       context "when given a path with directory components" do
         it "returns the path if it is executable" do