diff --git a/game.js b/game.js
index 135d556..176b131 100644
--- a/game.js
+++ b/game.js
@@ -3,7 +3,7 @@ var strolling = false;
 var maxStomachDigest = 10;
 var maxBowelsDigest = 10;
 
-var metric = true;
+var unit = "metric";
 
 var verbose = true;
 
@@ -41,7 +41,7 @@ var macro =
 
 function look()
 {
-  var line1 = "You are a " + length(macro.height, metric, true) + " tall " + macro.species + ". You weigh " + mass(macro.mass, metric) + ".";
+  var line1 = "You are a " + length(macro.height, unit, true) + " tall " + macro.species + ". You weigh " + mass(macro.mass, unit) + ".";
 
   var line2 = ""
 
@@ -90,9 +90,13 @@ function change_location()
 
 function toggle_units()
 {
-  metric = !metric;
+  switch(unit) {
+    case "metric": unit = "customary"; break;
+    case "customary": unit = "approx"; break;
+    case "approx": unit = "metric"; break;
+  }
 
-  document.getElementById("button-units").innerHTML = "Units: " + (metric ? "Metric" : "Customary");
+  document.getElementById("button-units").innerHTML = "Units: " + unit.charAt(0).toUpperCase() + unit.slice(1);
 
   update();
 }
@@ -361,8 +365,8 @@ function update(lines = [])
 
   log.scrollTop = log.scrollHeight;
 
-  document.getElementById("height").innerHTML = "Height: " + (metric ? metricLength(macro.height) : customaryLength(macro.height));
-  document.getElementById("mass").innerHTML = "Mass: " + (metric ? metricMass(macro.mass) : customaryMass(macro.mass));
+  document.getElementById("height").innerHTML = "Height: " + length(macro.height, unit);
+  document.getElementById("mass").innerHTML = "Mass: " + mass(macro.mass, unit);
 
   for (var type in victims) {
     if (victims.hasOwnProperty(type)) {
@@ -414,10 +418,10 @@ function grow()
   var heightDelta = newHeight - oldHeight;
   var massDelta = newMass - oldMass;
 
-  var heightStr = metric ? metricLength(heightDelta) : customaryLength(heightDelta);
-  var massStr = metric ? metricMass(massDelta) : customaryMass(massDelta);
+  var heightStr = length(heightDelta, unit);
+  var massStr = mass(massDelta, unit);
 
-  update(["Power surges through you as you grow " + heightStr + " and gain " + massStr,newline]);
+  update(["Power surges through you as you grow " + heightStr + " taller and gain " + massStr + " of mass",newline]);
 }
 
 // pop the list and digest that object
diff --git a/units.js b/units.js
index ba7ae67..5f431e8 100644
--- a/units.js
+++ b/units.js
@@ -2,14 +2,29 @@ function round(number,precision=3) {
   return Math.round(number*Math.pow(10,precision)) / Math.pow(10,precision);
 }
 
-function mass(kg, metric=true, singular=false) {
-  return metric ? metricMass(kg, singular) : customaryMass(kg, singular);
+function mass(kg, type="metric", singular=false) {
+  switch(type) {
+    case "metric": return metricMass(kg, singular); break;
+    case "customary": return customaryMass(kg, singular); break;
+    case "approx": return approxMass(kg, singular); break;
+  }
 }
 
-function length(m, metric=true, singular=false) {
-  return metric ? metricLength(m, singular) : customaryLength(m, singular);
+function length(m, type="metric", singular=false) {
+  switch(type) {
+    case "metric": return metricLength(m, singular); break;
+    case "customary": return customaryLength(m, singular); break;
+    case "approx": return approxLength(m, singular); break;
+  }
 }
 
+function volume(m3, type="metric", singular=false) {
+  switch(type) {
+    case "metric": return metricVolume(m3, singular); break;
+    case "customary": return customaryVolume(m3, singular); break;
+    case "approx": return approxVolume(m3, singular); break;
+  }
+}
 function metricMass(kg, singular=false) {
   if (kg < 1) {
     var mass = round(kg * 1000,0);
@@ -47,6 +62,25 @@ function customaryMass(kg, singular=false) {
   }
 }
 
+function approxMass(kg, singular=false) {
+  if (kg < 10000) {
+    var mass = round(kg/1000,2);
+    return (singular || mass == 1 ? "a car" : mass + " cars");
+  } else if (kg < 100000) {
+    var mass = round(kg/6000,2);
+    return (singular || mass == 1 ? "an elephant" : mass + " elephants");
+  } else if (kg < 1000000000) {
+    var mass = round(kg/54431.1,2);
+    return (singular || mass == 1 ? "a tank" : mass + " tanks");
+  } else if (kg < 1e21) {
+    var mass = round(kg/1.01605e8,2);
+    return (singular || mass == 1 ? "an aircraft carrier" : mass + " aircraft carriers");
+  } else {
+    var mass = round(kg/5.972e24,4);
+    return (singular || mass == 1 ? "the Earth" : mass + " Earths");
+  }
+}
+
 function metricLength(m, singular=false) {
   if (m < 1) {
     var length = round(m * 100,0);
@@ -75,3 +109,86 @@ function customaryLength(m, singular=false) {
     return length + (singular || length == 1 ? " mile" : " miles");
   }
 }
+
+function approxLength(m, singular=false) {
+  if (m < 1000) {
+    var length = round(m/49,1);
+    return length + (singular || length == 1 ? " football field" : " football fields");
+  } else if (m < 5000000) {
+    var length = round(m/449,1);
+    return length + (singular || length == 1 ? " Empire State Building" : " Empire State Buildings");
+  } else if (m < 3474574*2) {
+    var length = round(m/3474574,1);
+    return length + (singular || length == 1 ? " moon" : " moons");
+  } else if (m < 12.742e6*100) {
+    var length = round(m/12.742e6,1);
+    return length + (singular || length == 1 ? " earth" : " earths");
+  } else if (m < 149.6e12) {
+    var length = round(m/149.6e9,1);
+    return length + (singular || length == 1 ? " AU" : " AUs");
+  } else {
+    var length = round(m/9.4607e15,4);
+    return length + (singular || length == 1 ? " light year" : " light years");
+  }
+}
+
+function metricVolume(m3, singular=false) {
+  if (m3 < 1) {
+    var volume = round(m3/1000, 1);
+    return volume + (singular || volume == 1 ? " liter" : " liters");
+  } else if (m3 < 1000000) {
+    var volume = round(m3, 0);
+    return volume + (singular || volume == 1 ? " cubic meter" : " cubic meters");
+  } else if (m3 < 1e12){
+    var volume = round(m3/1e9, 6);
+    return volume + (singular || volume == 1 ? " cubic kilometer" : " cubic kilometers");
+  } else {
+    var volume = round(m3/1e9, 0);
+    return volume + (singular || volume == 1 ? " cubic kilometer" : " cubic kilometers");
+  }
+}
+
+function customaryVolume(m3, singular=false) {
+  var gallons = m3 * 264.172;
+  if (gallons < 1/16) {
+    var volume = round(gallons*128,0);
+    return volume + (singular || volume == 1 ? " fluid ounce" : " fluid ounces");
+  } else if (gallons < 1/4) {
+    var volume = round(gallons*16,1);
+    return volume + (singular || volume == 1 ? " cup" : " cups");
+  } else if (gallons < 1/2) {
+    var volume = round(gallons*8,1);
+    return volume + (singular || volume == 1 ? " pint" : " pints");
+  } else if (gallons < 1) {
+    var volume = round(gallons*4,1);
+    return volume + (singular || volume == 1 ? " quart" : " quarts");
+  } else if (gallons < 100) {
+    var volume = round(gallons,1);
+    return volume + (singular || volume == 1 ? " gallon" : " gallons");
+  } else {
+    var volume = round(gallons,0);
+    return volume + (singular || volume == 1 ? " gallon" : " gallons");
+  }
+}
+
+function approxVolume(m3, singular=false) {
+  if (m3 < 1/10000) {
+    var volume = round(m3*1e6,0);
+    return (singular || volume == 1 ? "a shot" : volume + " shots");
+  } else if (m3 < 1) {
+    var volume = round(m3*2000,0);
+    return (singular || volume == 1 ? "a glass" : volume + " glasses");
+  } else if (m3 < 10) {
+    var volume = round(m3*2.64,1);
+    return(singular || volume == 1 ? "a bathtub" : volume + " bathtubs");
+  } else if (m3 < 1e9) {
+    var volume = round(m3/1000,2);
+    return (singular || volume == 1 ? "an Olympic swimming pool" : volume + " Olympic swimming pools");
+  } else if (m3 < 1e15) {
+    var volume = round(m3/1.8919e10,3);
+    return (singular || volume == 1 ? "a Great Salt Lake" : volume + " Great Salt Lakes");
+  } else {
+    var volume = round(m3/3.547e17, 3);
+    return (singular || volume == 1 ? "an ocean" : volume + " oceans");
+  }
+}