diff --git a/Readme.md b/Readme.md
index b5a4b1f..3fc5413 100644
--- a/Readme.md
+++ b/Readme.md
@@ -46,6 +46,7 @@ These are keys in the options object you can pass to the progress bar along with
 These are tokens you can use in the format of your progress bar.
 
 - `:bar` the progress bar itself
+- `:wheel` rotating progress indicator
 - `:current` current tick number
 - `:total` total ticks
 - `:elapsed` time elapsed in seconds
diff --git a/examples/backnforth.js b/examples/backnforth.js
index ffc0dc6..e10f2a6 100644
--- a/examples/backnforth.js
+++ b/examples/backnforth.js
@@ -26,7 +26,7 @@ function forward() {
 function backward() {
   bar.tick(-1, { title: 'backward' });
   if (bar.curr == 0) {
-    bar.terminate();
+    bar.done();
   } else {
     setTimeout(backward, 20);
   }
diff --git a/examples/indeterminable.js b/examples/indeterminable.js
new file mode 100644
index 0000000..6e325f3
--- /dev/null
+++ b/examples/indeterminable.js
@@ -0,0 +1,22 @@
+/**
+ * An example to show how node-progress handles progress bar
+ * with unknown total number of ticks
+ */
+
+var ProgressBar = require('../');
+
+var bar = new ProgressBar(' [:wheel][:bar] :current/:total :elapseds :percent :etas', {
+    complete: '='
+  , incomplete: ' '
+  , width: 50
+  , total: -1 // total number of ticks is unknown
+});
+
+(function next() {
+  bar.tick(1);
+  if (bar.curr >= 150) {
+    bar.done();
+  } else {
+    setTimeout(next, 50);
+  }
+})();
diff --git a/lib/node-progress.js b/lib/node-progress.js
index 6480ffa..737c800 100644
--- a/lib/node-progress.js
+++ b/lib/node-progress.js
@@ -30,6 +30,7 @@ exports = module.exports = ProgressBar;
  * Tokens:
  *
  *   - `:bar` the progress bar itself
+ *   - `:wheel` rotating progress indicator
  *   - `:current` current tick number
  *   - `:total` total ticks
  *   - `:elapsed` time elapsed in seconds
@@ -57,8 +58,9 @@ function ProgressBar(fmt, options) {
 
   this.fmt = fmt;
   this.curr = options.curr || 0;
+  this.updates = 0;
   this.total = options.total;
-  this.width = options.width || this.total;
+  this.width = options.width || (this.total > 0 ? this.total : Infinity);
   this.clear = options.clear
   this.chars = {
     complete   : options.complete || '=',
@@ -80,6 +82,8 @@ function ProgressBar(fmt, options) {
  */
 
 ProgressBar.prototype.tick = function(len, tokens){
+  if (this.complete) return;
+
   if (len !== 0)
     len = len || 1;
 
@@ -98,13 +102,23 @@ ProgressBar.prototype.tick = function(len, tokens){
   }
 
   // progress complete
-  if (this.curr >= this.total) {
-    if (this.renderThrottleTimeout) this.render();
-    this.complete = true;
-    this.terminate();
-    this.callback(this);
-    return;
-  }
+  if (this.total > 0 && this.curr >= this.total) this.done();
+};
+
+/**
+ * complete the progress bar with optional `tokens`.
+ *
+ * @param {object} tokens
+ * @api public
+ */
+
+ProgressBar.prototype.done = function(tokens){
+  if (tokens) this.tokens = tokens;
+
+  this.complete = true;
+  this.render();
+  this.terminate();
+  this.callback(this);
 };
 
 /**
@@ -123,44 +137,69 @@ ProgressBar.prototype.render = function (tokens) {
 
   if (!this.stream.isTTY) return;
 
-  var ratio = this.curr / this.total;
-  ratio = Math.min(Math.max(ratio, 0), 1);
-
-  var percent = ratio * 100;
-  var incomplete, complete, completeLength;
+  this.updates++;
   var elapsed = new Date - this.start;
-  var eta = (percent == 100) ? 0 : elapsed * (this.total / this.curr - 1);
   var rate = this.curr / (elapsed / 1000);
+  var ratio, eta, percent;
+  if (this.total > 0) {
+    ratio = this.curr / this.total;
+    ratio = Math.min(Math.max(ratio, 0), 1);
+    percent = ratio * 100;
+    eta = (percent == 100) ? 0 : elapsed * (this.total / this.curr - 1);
+    eta = (isNaN(eta) || !isFinite(eta)) ? '0.0' : (eta / 1000).toFixed(1);
+    percent = percent.toFixed(0);
+  } else {
+    // indeterminable progress bar (unknown total)
+    percent = this.complete ? '100' : '?';
+    eta = this.complete ? '0.0' : '?';
+  }
 
   /* populate the bar template with percentages and timestamps */
   var str = this.fmt
+    .replace(':wheel', this.complete ? '+' : ['/', '-', '\\', '|'][this.updates % 4])
     .replace(':current', this.curr)
-    .replace(':total', this.total)
+    .replace(':total', this.total > 0 ? this.total : '?')
     .replace(':elapsed', isNaN(elapsed) ? '0.0' : (elapsed / 1000).toFixed(1))
-    .replace(':eta', (isNaN(eta) || !isFinite(eta)) ? '0.0' : (eta / 1000)
-      .toFixed(1))
-    .replace(':percent', percent.toFixed(0) + '%')
+    .replace(':eta', eta)
+    .replace(':percent', percent + '%')
     .replace(':rate', Math.round(rate));
 
   /* compute the available space (non-zero) for the bar */
   var availableSpace = Math.max(0, this.stream.columns - str.replace(':bar', '').length);
   if(availableSpace && process.platform === 'win32'){
-    availableSpace = availableSpace - 1; 
+    availableSpace = availableSpace - 1;
   }
-  
+
   var width = Math.min(this.width, availableSpace);
 
   /* TODO: the following assumes the user has one ':bar' token */
-  completeLength = Math.round(width * ratio);
-  complete = Array(Math.max(0, completeLength + 1)).join(this.chars.complete);
-  incomplete = Array(Math.max(0, width - completeLength + 1)).join(this.chars.incomplete);
-
-  /* add head to the complete string */
-  if(completeLength > 0)
-    complete = complete.slice(0, -1) + this.chars.head;
+  var bar;
+  if (this.complete) {
+    // complete progress bar
+    bar = Array(width + 1).join(this.chars.complete);
+  } else if (this.total > 0) {
+    var incomplete, complete, completeLength;
+    completeLength = Math.round(width * ratio);
+    complete = Array(Math.max(0, completeLength + 1)).join(this.chars.complete);
+    incomplete = Array(Math.max(0, width - completeLength + 1)).join(this.chars.incomplete);
+
+    /* add head to the complete string */
+    if(completeLength > 0)
+      complete = complete.slice(0, -1) + this.chars.head;
+
+    bar = complete + incomplete;
+  } else {
+    // incomplete indeterminable progress bar
+    bar = Array(width);
+    for (var i = 0; i < width; i++) {
+      var dist = (((i - this.updates) % width) + width) % width; // (i - this.updates) mod width
+      bar[i] = dist < 3 ? this.chars.complete : this.chars.incomplete;
+    }
+    bar = bar.join('');
+  }
 
   /* fill in the actual progress bar */
-  str = str.replace(':bar', complete + incomplete);
+  str = str.replace(':bar', bar);
 
   /* replace the extra tokens */
   if (this.tokens) for (var key in this.tokens) str = str.replace(':' + key, this.tokens[key]);
@@ -188,10 +227,14 @@ ProgressBar.prototype.render = function (tokens) {
  */
 
 ProgressBar.prototype.update = function (ratio, tokens) {
-  var goal = Math.floor(ratio * this.total);
-  var delta = goal - this.curr;
+  if (this.total > 0) {
+    var goal = Math.floor(ratio * this.total);
+    var delta = goal - this.curr;
 
-  this.tick(delta, tokens);
+    this.tick(delta, tokens);
+  } else if (ratio == 1) {
+    this.done(tokens);
+  }
 };
 
 /**