diff --git a/README.md b/README.md
index 21764a3..65f0c70 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,7 @@ npm install node-units
 * `importDB(file_name, cb)` - imports a custom unit database, `cb` takes a single argument `err`
 * `importDBSync(file_name)` - the sync version of `importDB`
 * `getDB()` - returns he currently used database of units as an object
-* `convert(type, value, from, to)` - converts `value` of `from` to `to`, returns the result or raises exception if conversion cannot be made
+* `convert(conversion_string)` - where `conversion_string` is of the form `<value> <from_unit> to <to_unit>`
 
 ### Properties
 * `types` - `types` is an object containing constants for each unit group.
@@ -31,10 +31,10 @@ npm install node-units
 ```javascript
 var units = require('node-units');
 
-var result = units.convert('volume', 5, 'gill', 'mL');
+var result = units.convert('5 gills to mL');
 // result == 591.4705
 
-units.convert(units.types.TIME, 5, 'day', 'second');
+units.convert('five days to seconds');
 ```
 
 ### Custom Units
@@ -42,9 +42,9 @@ units.convert(units.types.TIME, 5, 'day', 'second');
 With `node-units` you can import custom unit definitions from files defined like the following:
 ```
 group:
-  long_name,longname,ln    1ln
-  another_unit,au          5ln
-  one_more,om              2au
+  longname,longname,ln    1ln
+  anotherunit,au          5ln
+  onemore,om              2au
 ```
 
 ```javascript
@@ -52,7 +52,7 @@ var units = require('node-units');
 
 units.importDBSync('my_custom.units');
 
-var result = units.convert(units.types.GROUP, 5, 'au', 'one_more');
+var result = units.convert('five au to onemores');
 // result == 10
 ```
 
@@ -68,7 +68,7 @@ var units = require('node-units');
 
 units.importDBSync('my_custom.units');
 
-var result = units.convert('time', 5, 'minute', 's');
+var result = units.convert('5 minutes to s');
 // result == 250
 ```
 
diff --git a/examples/custom/index.js b/examples/custom/index.js
new file mode 100644
index 0000000..c76b27f
--- /dev/null
+++ b/examples/custom/index.js
@@ -0,0 +1,10 @@
+var path = require('path');
+var units = require('../../');
+
+var db = path.join(path.dirname(module.filename), 'my_custom.units');
+units.importDBSync(db);
+
+console.log(units.convert('5 buttons to widgets'));
+
+
+console.log(units.convert('30 jings to jong'));
diff --git a/examples/custom/my_custom.units b/examples/custom/my_custom.units
new file mode 100644
index 0000000..8fd0bf5
--- /dev/null
+++ b/examples/custom/my_custom.units
@@ -0,0 +1,9 @@
+elements:
+  button,btn		5wg
+  widget,wg		2tbl
+  table,tbl		1tbl
+
+things:
+  jing			2jabber
+  jabber		30jong
+  jong			1jong
diff --git a/examples/simple/index.js b/examples/simple/index.js
new file mode 100644
index 0000000..4f85b04
--- /dev/null
+++ b/examples/simple/index.js
@@ -0,0 +1,13 @@
+var units = require('../../');
+
+var result = units.convert('20 quarts to gallons');
+
+console.log(result === 5);
+
+
+try{
+    var value = units.convert('5 days to gallon');
+    console.log(value);
+} catch(e){
+    console.log(e);
+}
diff --git a/lib/default.units b/lib/default.units
index c0c2c03..4140e12 100644
--- a/lib/default.units
+++ b/lib/default.units
@@ -7,9 +7,9 @@ time:
 volume:
   liter,L		1L
   milliliter,mL		0.001L
-  gallon,gal		3.78541L
-  pint			0.473176L
-  quart,qt		0.946353L
+  gallon,gal		8pint
+  pint			0.125gal
+  quart,qt		2pint
   tablespoon,tbl	0.03125pint
   teaspoon,tsp		0.33333333333tbl
   cup			16tbl
diff --git a/lib/index.js b/lib/index.js
index 95d0364..b1abe82 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -1,11 +1,16 @@
 var path = require('path');
 var fs = require('fs');
+var numerizer = require('numerizer');
 
 var types = {};
 
+var conversion_regex = /^(.*?)\s([a-zA-Z]+)\sto\s([a-zA-Z]+)$/i;
+
 var db_regex = /[a-zA-Z]+:\n([\s\t]+([a-zA-Z]+,?)+[\s\t]+[0-9.]+[a-zA-Z]+\n)+/g;
 var unit_database = {};
 
+var forms = [/s$/i, /es$/i, /ies$/i];
+
 var parseSection = function(section){
     var lines = section.split('\n');
     var section_name = lines.shift();
@@ -23,12 +28,12 @@ var parseSection = function(section){
 
 	var names = next[0].replace(/[\s\t]/g, '').split(',');
 	var value = next[1].replace(/[\s\t]/g, '').match(/([0-9.]+)|([a-zA-Z]+)/g);
-	var unit = value[1];
+	var unit = value[1].toLowerCase();
 	value = parseFloat(value[0]);
 
 	names.forEach(function(name){
-	    unit_database[section_name][name] = {'unit': unit,
-						 'value': value};
+	    unit_database[section_name][name.toLowerCase()] = {'unit': unit,
+							       'value': value};
 	});
     }
 };
@@ -81,6 +86,26 @@ var convert = function(type, value, from, to, max_calls){
 };
 
 
+var get_variations = function(unit){
+    var variations = [unit];
+    forms.forEach(function(form){
+	if(unit.match(form)){
+	    variations.push(unit.replace(form, ''));
+	}
+    });
+    return variations;
+};
+
+
+var determine_type = function(variations){
+    for(var i in types){
+	for(var k in variations){
+	    if(unit_database[types[i]][variations[k]] !== undefined){
+		return {'type': types[i], 'unit': variations[k]};
+	    }
+	}
+    }
+};
 
 var default_db = path.join(path.dirname(module.filename), 'default.units');
 importDBSync(default_db);
@@ -92,20 +117,43 @@ return module.exports = {
     getDB: function(){
 	return unit_database;
     },
-    convert: function(type, value, from, to){
-	type = type.toLowerCase();
-
-	if(unit_database[type] == undefined){
-	    throw 'Unit group ' + type + ' does not exist';
-	} else if(unit_database[type][from] == undefined){
-	    throw 'Unit ' + from + ' does not belong to unit group ' + type;
-	} else if(unit_database[type][to] == undefined){
-	    throw 'Unit ' + to + ' does not belong to unit group ' + type;
+    convert: function(str){
+	var type, value, from, to, max_tries;
+
+	var parts = conversion_regex.exec(str);
+	if(parts == null){
+	    throw 'Invalid conversion string: "' + str + '", expected "<value> <from_unit> to <to_unit>"';
+	    return;
+	}
+
+	value = parseFloat(numerizer(parts[1]));
+	var from_variations = get_variations(parts[2].toLowerCase());
+	var to_variations = get_variations(parts[3].toLowerCase());
+
+	var from_type = determine_type(from_variations);
+	var to_type = determine_type(to_variations);
+
+	if(!from_type){
+	    throw 'Unknown unit: "' + parts[2] + '"';
+	    return;
 	}
+	if(!to_type){
+	    throw 'Unknown unit: "' + parts[3] + '"';
+	    return;
+	}
+
+	if(from_type.type !== to_type.type){
+	    throw 'Units "' + from_type.unit + '" and "' + to_type.unit + '" do not belong in the same unit group';
+	    return;
+	}
+
+	type = from_type.type;
+	from = from_type.unit;
+	to = to_type.unit;
 
-	var result = convert(type, value, from, to, 5);
+        var result = convert(type, value, from, to, max_tries);
 	if(result == undefined){
-	    throw 'Conversion of ' + from + ' to ' + to + ' was not possible';
+	    throw 'Conversion of "' + from + '" to "' + to + '" was not possible';
 	} else{
 	    return result;
 	}
diff --git a/package.json b/package.json
index 5448ca1..a51af27 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "node-units",
-  "version": "0.1.0",
+  "version": "0.1.1",
   "description": "Node.JS unit conversion library with customizable units",
   "main": "lib/index.js",
   "directories": {
@@ -21,5 +21,11 @@
     "conversion"
   ],
   "author": "Brett Langdon <brett@blangdon.com> (www.brett.is)",
-  "license": "MIT"
+  "license": "MIT",
+  "dependencies": {
+    "numerizer": "0.0.2"
+  },
+  "devDependencies": {
+    "mocha": "*"
+  }
 }