diff --git a/nengo_gui/static/components/netgraph.js b/nengo_gui/static/components/netgraph.js
index 8b50075c..18c1ed31 100644
--- a/nengo_gui/static/components/netgraph.js
+++ b/nengo_gui/static/components/netgraph.js
@@ -70,6 +70,17 @@ Nengo.NetGraph = function(parent, args) {
         }
     });
 
+    Object.defineProperty(this, 'kept_time', {
+        get: function() {
+            return Nengo.config.kept_time;
+        },
+        set: function(val) {
+            if (val === this.kept_time) { return; }
+            Nengo.config.kept_time = val;
+            sim.time_slider.update_kept_time(val);
+        }
+    });
+
     // Do networks have transparent backgrounds?
     Object.defineProperty(this, 'transparent_nets', {
         get: function() {
diff --git a/nengo_gui/static/config.js b/nengo_gui/static/config.js
index 4bc75b4b..acee34de 100644
--- a/nengo_gui/static/config.js
+++ b/nengo_gui/static/config.js
@@ -26,6 +26,7 @@ Nengo.Config = function(parent, args) {
     define_option("aspect_resize", false);
     define_option("zoom_fonts", false);
     define_option("font_size", 100);
+    define_option("kept_time", 4);
 
     // Ace editor options
     define_option("hide_editor", false);
diff --git a/nengo_gui/static/modal.js b/nengo_gui/static/modal.js
index 0eac0940..d8d7dd4b 100644
--- a/nengo_gui/static/modal.js
+++ b/nengo_gui/static/modal.js
@@ -181,6 +181,10 @@ Nengo.Modal.prototype.tabbed_body = function(tabinfo) {
 Nengo.Modal.prototype.main_config = function() {
     this.clear_body();
 
+    // Range on time kept, currently picked arbitrarily
+    var min_kept_time = 1;
+    var max_kept_time = 10;
+
     var $form = $('<form class="form-horizontal" id ' +
         '="myModalForm"/>').appendTo(this.$body);
     $('<div class="form-group" id="config-fontsize-group">' +
@@ -196,6 +200,21 @@ Nengo.Modal.prototype.main_config = function() {
         '<span class="help-block with-errors">As a percentage of' +
             ' the base size</span>' +
       '</div>' +
+      '<div class="form-group" id="config-kept-time-group">' +
+        '<label for="kept-time" class="control-label">' +
+            'Time kept</label>' +
+        '<div class="input-group col-xs-2">' +
+          '<input type="number" min="' + min_kept_time +
+          '" max="' + max_kept_time + '" step="1" ' +
+            'maxlength="3" class="form-control" id="kept-time"' +
+                ' data-error="' + min_kept_time +
+                ' to ' + max_kept_time + ' seconds"' +
+                ' required>' +
+          '<span class="input-group-addon">s</span>' +
+        '</div>' +
+        '<span class="help-block with-errors">Amount of data to' +
+            ' save on the time slider</span>' +
+      '</div>' +
       '<div class="form-group">' +
         '<div class="checkbox">' +
           '<label for="zoom-fonts" class="control-label">' +
@@ -272,6 +291,14 @@ Nengo.Modal.prototype.main_config = function() {
     });
     $('#config-fontsize').attr('data-my_validator', 'custom');
 
+    $('#kept-time').val(Nengo.netgraph.kept_time);
+    $('#kept-time').bind('keyup input', function () {
+        var kept_time = parseInt($('#kept-time').val());
+        if (kept_time >= min_kept_time && kept_time <= max_kept_time) {
+            Nengo.netgraph.kept_time = kept_time;
+        }
+    });
+
     $('#config-backend').change(function () {
         sim.set_backend($('#config-backend').val());
     });
diff --git a/nengo_gui/static/sim_control.js b/nengo_gui/static/sim_control.js
index aed42f5d..fdd3b2c3 100644
--- a/nengo_gui/static/sim_control.js
+++ b/nengo_gui/static/sim_control.js
@@ -336,6 +336,32 @@ Nengo.TimeSlider.prototype.reset = function() {
     this.sim.div.dispatchEvent(new Event('adjust_time'));
 }
 
+Nengo.TimeSlider.prototype.update_kept_time = function(kept_time) {
+    this.kept_time = kept_time;
+
+    /** update the limits on the time axis */
+    this.kept_scale.domain([this.last_time - this.kept_time, this.last_time]);
+
+    var width = this.sim.div.clientWidth - 290;
+    var height = this.sim.div.clientHeight - 20;
+    this.kept_scale.range([0, width]);
+    this.shown_div.style.width = width * this.shown_time / this.kept_time;
+
+    // If the shown time window will go off screen, move it on screen
+    if (this.first_shown_time < this.last_time - this.kept_time) {
+        this.first_shown_time = this.last_time - this.kept_time;
+    }
+
+    x = this.kept_scale(this.first_shown_time);
+    Nengo.set_transform(this.shown_div, x, 0);
+
+    /** update the time axis display */
+    this.axis_g.call(this.axis);
+
+    /** update any components who need to know the time changed */
+    this.sim.div.dispatchEvent(new Event('adjust_time'));
+}
+
 /**
  * Adjust size and location of parts based on overall size
  */
diff --git a/nengo_gui/static/top_toolbar.js b/nengo_gui/static/top_toolbar.js
index efd18318..07259e0f 100644
--- a/nengo_gui/static/top_toolbar.js
+++ b/nengo_gui/static/top_toolbar.js
@@ -114,6 +114,7 @@ Nengo.Toolbar.prototype.config_modal_show = function() {
                     font_size: Nengo.netgraph.font_size,
                     aspect_resize: Nengo.netgraph.aspect_resize,
                     sync_editor: Nengo.ace.auto_update,
+                    kept_time: sim.time_slider.kept_time,
                     transparent_nets: Nengo.netgraph.transparent_nets};
 
     Nengo.modal.title('Configure Options');
@@ -134,6 +135,7 @@ Nengo.Toolbar.prototype.config_modal_show = function() {
             Nengo.netgraph.zoom_fonts = original["zoom"];
             Nengo.netgraph.font_size = original["font_size"];
             Nengo.netgraph.transparent_nets = original["transparent_nets"];
+            Nengo.netgraph.kept_time = original["kept_time"];
             Nengo.netgraph.aspect_resize = original["aspect_resize"];
             Nengo.ace.auto_update = original["auto_update"];
             $('#cancel-button').attr('data-dismiss', 'modal');