diff --git a/Cog.xcodeproj/xcshareddata/xcschemes/SecondsFormatterTests.xcscheme b/Cog.xcodeproj/xcshareddata/xcschemes/SecondsFormatterTests.xcscheme
new file mode 100644
index 000000000..478910225
--- /dev/null
+++ b/Cog.xcodeproj/xcshareddata/xcschemes/SecondsFormatterTests.xcscheme
@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "1240"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <Testables>
+         <TestableReference
+            skipped = "NO">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "3D42D2732642BEA0002A170C"
+               BuildableName = "SecondsFormatterTests.xctest"
+               BlueprintName = "SecondsFormatterTests"
+               ReferencedContainer = "container:Cog.xcodeproj">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>
diff --git a/Formatters/SecondsFormatter.m b/Formatters/SecondsFormatter.m
index e28f598cb..17fccb80f 100644
--- a/Formatters/SecondsFormatter.m
+++ b/Formatters/SecondsFormatter.m
@@ -34,64 +34,129 @@
 	if (isnan(floatValue)) { return @"NaN"; }
 	if (isinf(floatValue)) { return @"Inf"; }
 	
-	int totalSeconds		= (int)floatValue;
+	BOOL isNegative = floatValue < 0;
+
+	int totalSeconds = (int)(isNegative ? -floatValue : floatValue);
 	
 	int seconds	= totalSeconds % 60;
 	int minutes	= totalSeconds / 60;
 	int hours = 0;
 	int days = 0;
 	
-	while(60 <= minutes) {
+	while (60 <= minutes) {
 		minutes -= 60;
 		++hours;
 	}
 	
-	while(24 <= hours) {
+	while (24 <= hours) {
 		hours -= 24;
 		++days;
 	}
 	
 	NSString *result = nil;
 	
-	if(0 < days) {
-		result = [NSString stringWithFormat:@"%i:%.2i:%.2i:%.2i", days, hours, minutes, seconds];
+	const char *signPrefix = isNegative ? "-" : "";
+	
+	if (0 < days) {
+		result = [NSString stringWithFormat:@"%s%i:%.2i:%.2i:%.2i", signPrefix, days, hours, minutes, seconds];
 	}
-	else if(0 < hours) {
-		result = [NSString stringWithFormat:@"%i:%.2i:%.2i", hours, minutes, seconds];
+	else if (0 < hours) {
+		result = [NSString stringWithFormat:@"%s%i:%.2i:%.2i", signPrefix, hours, minutes, seconds];
 	}
-	else if(0 < minutes) {
-		result = [NSString stringWithFormat:@"%i:%.2i", minutes, seconds];
+	else if (0 < minutes) {
+		result = [NSString stringWithFormat:@"%s%i:%.2i", signPrefix, minutes, seconds];
 	}
 	else {
-		result = [NSString stringWithFormat:@"0:%.2i", seconds];
+		result = [NSString stringWithFormat:@"%s0:%.2i", signPrefix, seconds];
 	}
 	
 	return result;
 }
 
-- (BOOL)getObjectValue:(out id  _Nullable __autoreleasing *)object forString:(NSString *)string errorDescription:(out NSString * _Nullable __autoreleasing *)error
+- (BOOL)getObjectValue:(out id  _Nullable __autoreleasing *)object
+			 forString:(NSString *)string
+	  errorDescription:(out NSString * _Nullable __autoreleasing *)error
 {
-	NSScanner		*scanner		= nil;
-	BOOL			result			= NO;
-	int				value			= 0;
-	int				seconds			= 0;
+	NSScanner *scanner = [NSScanner scannerWithString:string];
 	
-	scanner		= [NSScanner scannerWithString:string];
+	BOOL result = NO;
 	
-	while(NO == [scanner isAtEnd]) {
+	const int segmentCount = 4;
+	const int lastSegment = segmentCount - 1;
+	int segments[segmentCount] = {-1, -1, -1, -1};
+	int lastScannedSegment = -1;
+
+	BOOL isNegative = NO;
+	
+	if ([scanner isAtEnd] == NO) {
+		isNegative = [scanner scanString:@"-" intoString:NULL];
 		
-		// Grab a value
-		if([scanner scanInt:&value]) {
-			seconds		*= 60;
-			seconds		+= value;
-			result		= YES;
+		int segmentIndex = 0;
+		
+		while (NO == [scanner isAtEnd]) {
+			// Grab a value
+			if ([scanner scanInt:&(segments[segmentIndex])] == NO) {
+				segments[segmentIndex] = -1;
+				break;
+			}
+			
+			if (segmentIndex == lastSegment) {
+				break;
+			}
+			
+			// Grab the separator, if present
+			if ([scanner scanString:@":" intoString:NULL] == NO) {
+				break;
+			}
+			
+			segmentIndex += 1;
 		}
 		
-		// Grab the separator, if present
-		[scanner scanString:@":" intoString:NULL];
+		lastScannedSegment = segmentIndex;
 	}
 	
-	if(result && NULL != object) {
+	int seconds = 0;
+	
+	const BOOL hasDaysSegment = (lastScannedSegment == 3);
+	const BOOL hasHoursSegment = (lastScannedSegment >= 2);
+
+	for (int i = 0; i <= lastScannedSegment; i += 1) {
+		if (segments[i] < 0) {
+			break;
+		}
+		
+		if (hasDaysSegment &&
+			(i == 1)) {
+			// Special case for days.
+			seconds *= 24;
+		}
+		else {
+			seconds *= 60;
+		}
+		
+		const BOOL isDaysSegment = (hasDaysSegment && (i == 0));
+		const BOOL isHoursSegment = (hasHoursSegment && (((lastScannedSegment == 3) && (i == 1)) || ((lastScannedSegment == 2) && (i == 0))));
+
+		if (isDaysSegment ||
+			((isDaysSegment == NO) &&
+			 ((isHoursSegment && (segments[i] < 24)) ||
+			  ((isHoursSegment == NO) &&
+			   (segments[i] < 60))))) {
+			seconds += segments[i];
+		}
+		else {
+			result = NO;
+			break;
+		}
+		
+		if (i == 0) {
+			result = YES;
+		}
+	}
+	
+	if (isNegative) { seconds *= -1; }
+
+	if (result && NULL != object) {
 		*object = [NSNumber numberWithInt:seconds];
 	}
 	else if(NULL != error) {
diff --git a/SecondsFormatterTests/SecondsFormatterTests.m b/SecondsFormatterTests/SecondsFormatterTests.m
index 9253458dd..56e1b5069 100644
--- a/SecondsFormatterTests/SecondsFormatterTests.m
+++ b/SecondsFormatterTests/SecondsFormatterTests.m
@@ -27,11 +27,6 @@
 	[super tearDown];
 }
 
-- (void)testExample {
-    // This is an example of a functional test case.
-    // Use XCTAssert and related functions to verify your tests produce the correct results.
-}
-
 - (void)testPositive
 {
 	NSDictionary *testsDict =
@@ -62,6 +57,66 @@
 	}];
 }
 
+- (void)testNegative
+{
+	NSDictionary *testsDict =
+	@{
+		// key: test name, value: test string
+		@"Negative One Second": @"-0:01",
+		@"Negative One Minute": @"-1:00",
+		@"Negative One Hour": @"-1:00:00",
+		@"Negative One Day": @"-1:00:00:00",
+		@"Negative One of Each": @"-1:01:01:01",
+	};
+	
+#define TEST_INFO	@"Test name: %@, Source string: %@", testName, string
+	
+	NSFormatter *secondsFormatter = [[SecondsFormatter alloc] init];
+	
+	[testsDict enumerateKeysAndObjectsUsingBlock:
+	 ^(NSString *testName, NSString *string, BOOL * _Nonnull stop) {
+		NSNumber *value;
+		BOOL result =
+		[secondsFormatter getObjectValue:&value
+							   forString:string
+						errorDescription:NULL];
+		XCTAssertTrue(result, TEST_INFO);
+		NSString *timeString = [secondsFormatter stringForObjectValue:value];
+		XCTAssertEqualObjects(string, timeString, TEST_INFO);
+	}];
+}
+
+- (void)testMalformed
+{
+	NSDictionary *testsDict =
+	@{
+		// key: test name, value: test string
+		@"Empty String": @"",
+		@"Random String": @"abc",
+		@"Solitary Minus": @"-",
+		@"Malformed Seconds": @"0:60",
+		@"Malformed Minutes": @"60:00",
+		@"Malformed Hours": @"24:00:00",
+		@"Illegal #1": @":00",
+		@"Illegal #2": @"-:00",
+	};
+	
+#define TEST_INFO	@"Test name: %@, Source string: %@", testName, string
+	
+	NSFormatter *secondsFormatter = [[SecondsFormatter alloc] init];
+	
+	[testsDict enumerateKeysAndObjectsUsingBlock:
+	 ^(NSString *testName, NSString *string, BOOL * _Nonnull stop) {
+		NSNumber *value;
+		BOOL result =
+		[secondsFormatter getObjectValue:&value
+							   forString:string
+						errorDescription:NULL];
+		XCTAssertFalse(result, TEST_INFO);
+	}];
+}
+
+
 #if 0
 - (void)testPerformanceExample
 {