diff --git a/nbgrader/alembic/env.py b/nbgrader/alembic/env.py
index 058378b9d..cdc897f26 100644
--- a/nbgrader/alembic/env.py
+++ b/nbgrader/alembic/env.py
@@ -13,9 +13,8 @@
 
 # add your model's MetaData object here
 # for 'autogenerate' support
-# from myapp import mymodel
-# target_metadata = mymodel.Base.metadata
-target_metadata = None
+from nbgrader.api import Base
+target_metadata = Base.metadata
 
 # other values from the config, defined by the needs of env.py,
 # can be acquired:
diff --git a/nbgrader/alembic/versions/724cde206c17_add_extra_credit_column.py b/nbgrader/alembic/versions/724cde206c17_add_extra_credit_column.py
new file mode 100644
index 000000000..dedb88ddd
--- /dev/null
+++ b/nbgrader/alembic/versions/724cde206c17_add_extra_credit_column.py
@@ -0,0 +1,24 @@
+"""add extra credit column
+
+Revision ID: 724cde206c17
+Revises: 50a4d84c131a
+Create Date: 2017-06-02 13:05:22.347671
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = '724cde206c17'
+down_revision = '50a4d84c131a'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    op.add_column('grade', sa.Column('extra_credit', sa.Float(), nullable=True))
+
+
+def downgrade():
+    op.drop_column('grade', 'extra_credit')
diff --git a/nbgrader/api.py b/nbgrader/api.py
index 0b3ec079d..7928506d6 100644
--- a/nbgrader/api.py
+++ b/nbgrader/api.py
@@ -672,6 +672,9 @@ class Grade(Base):
     #: Score assigned by a human grader
     manual_score = Column(Float())
 
+    #: Extra credit assigned by a human grader
+    extra_credit = Column(Float())
+
     #: Whether a score needs to be assigned manually. This is True by default.
     needs_manual_grade = Column(Boolean, default=True, nullable=False)
 
@@ -682,8 +685,8 @@ class Grade(Base):
     #: for the score.
     score = column_property(case(
         [
-            (manual_score != None, manual_score),
-            (auto_score != None, auto_score)
+            (manual_score != None, manual_score + case([(extra_credit != None, extra_credit)], else_=literal_column("0.0"))),
+            (auto_score != None, auto_score + case([(extra_credit != None, extra_credit)], else_=literal_column("0.0")))
         ],
         else_=literal_column("0.0")
     ))
@@ -713,6 +716,7 @@ def to_dict(self):
             "student": self.student.id,
             "auto_score": self.auto_score,
             "manual_score": self.manual_score,
+            "extra_credit": self.extra_credit,
             "max_score": self.max_score,
             "needs_manual_grade": self.needs_manual_grade,
             "failed_tests": self.failed_tests,
diff --git a/nbgrader/docs/source/api/models.rst b/nbgrader/docs/source/api/models.rst
index dc1ea4333..30b5e53ce 100644
--- a/nbgrader/docs/source/api/models.rst
+++ b/nbgrader/docs/source/api/models.rst
@@ -82,6 +82,8 @@ Master version of an assignment
 
     .. autoattribute:: needs_manual_grade
 
+    .. autoattribute:: kernelspec
+
     .. automethod:: to_dict
 
 .. autoclass:: GradeCell
@@ -257,6 +259,8 @@ Submitted assignments
 
     .. autoattribute:: manual_score
 
+    .. autoattribute:: extra_credit
+
     .. autoattribute:: score
 
     .. autoattribute:: max_score
diff --git a/nbgrader/docs/source/spelling_wordlist.txt b/nbgrader/docs/source/spelling_wordlist.txt
index be768a0ae..79214ce00 100644
--- a/nbgrader/docs/source/spelling_wordlist.txt
+++ b/nbgrader/docs/source/spelling_wordlist.txt
@@ -93,6 +93,7 @@ JUPYTER
 Jupyter
 jupyter
 jupyterhub
+kernelspec
 lgpage
 linkcheck
 linux
diff --git a/nbgrader/server_extensions/formgrader/apihandlers.py b/nbgrader/server_extensions/formgrader/apihandlers.py
index 3106a3467..377eb3515 100644
--- a/nbgrader/server_extensions/formgrader/apihandlers.py
+++ b/nbgrader/server_extensions/formgrader/apihandlers.py
@@ -46,6 +46,7 @@ def put(self, grade_id):
 
         data = self.get_json_body()
         grade.manual_score = data.get("manual_score", None)
+        grade.extra_credit = data.get("extra_credit", None)
         if grade.manual_score is None and grade.auto_score is None:
             grade.needs_manual_grade = True
         else:
diff --git a/nbgrader/server_extensions/formgrader/static/css/formgrade.css b/nbgrader/server_extensions/formgrader/static/css/formgrade.css
index 97d928050..001fcd06a 100644
--- a/nbgrader/server_extensions/formgrader/static/css/formgrade.css
+++ b/nbgrader/server_extensions/formgrader/static/css/formgrade.css
@@ -102,7 +102,7 @@ div.nbgrader_cell .input_area {
     border: none;
 }
 
-.score {
+.score, .extra-credit {
     color: black;
     height: 29px;
     margin-left: 1em;
diff --git a/nbgrader/server_extensions/formgrader/static/js/models.js b/nbgrader/server_extensions/formgrader/static/js/models.js
index 134049cbc..dbe943af7 100644
--- a/nbgrader/server_extensions/formgrader/static/js/models.js
+++ b/nbgrader/server_extensions/formgrader/static/js/models.js
@@ -2,6 +2,7 @@ var GradeUI = Backbone.View.extend({
 
     events: {
         "change .score": "save",
+        "change .extra-credit": "save",
         "click .full-credit": "assignFullCredit",
         "click .no-credit": "assignNoCredit",
         "click .mark-graded": "save"
@@ -10,6 +11,7 @@ var GradeUI = Backbone.View.extend({
     initialize: function () {
         this.$glyph = this.$el.find(".score-saved");
         this.$score = this.$el.find(".score");
+        this.$extra_credit = this.$el.find(".extra-credit");
         this.$mark_graded = this.$el.find(".mark-graded");
 
         this.listenTo(this.model, "change", this.render);
@@ -17,11 +19,13 @@ var GradeUI = Backbone.View.extend({
         this.listenTo(this.model, "sync", this.animateSaved);
 
         this.$score.attr("placeholder", this.model.get("auto_score"));
+        this.$extra_credit.attr("placeholder", 0.0);
         this.render();
     },
 
     render: function () {
         this.$score.val(this.model.get("manual_score"));
+        this.$extra_credit.val(this.model.get("extra_credit"));
         if (this.model.get("needs_manual_grade")) {
             this.$score.addClass("needs_manual_grade");
             if (this.model.get("manual_score") !== null) {
@@ -34,22 +38,36 @@ var GradeUI = Backbone.View.extend({
     },
 
     save: function () {
+        var score, extra_credit;
         if (this.$score.val() === "") {
-            this.model.save({"manual_score": null});
+            score = null;
         } else {
             var val = this.$score.val();
             var max_score = this.model.get("max_score");
             if (val > max_score) {
-                this.animateInvalidValue();
-                this.model.save({"manual_score": max_score});
+                this.animateInvalidValue(this.$score);
+                score = max_score;
             } else if (val < 0) {
-                this.animateInvalidValue();
-                this.model.save({"manual_score": 0});
+                this.animateInvalidValue(this.$score);
+                score = 0;
             } else {
-                this.model.save({"manual_score": val});
+                score = val;
             }
         }
 
+        if (this.$extra_credit.val() == "") {
+            extra_credit = null;
+        } else {
+            var val = this.$extra_credit.val();
+            if (val < 0) {
+                this.animateInvalidValue(this.$extra_credit);
+                extra_credit = 0;
+            } else {
+                extra_credit = val;
+            }
+        }
+
+        this.model.save({"manual_score": score, "extra_credit": extra_credit});
         this.render();
     },
 
@@ -69,14 +87,14 @@ var GradeUI = Backbone.View.extend({
         $(document).trigger("finished_saving");
     },
 
-    animateInvalidValue: function () {
+    animateInvalidValue: function (elem) {
         var that = this;
-        this.$score.animate({
+        elem.animate({
             "background-color": "#FF8888",
             "border-color": "red"
         }, 100, undefined, function () {
             setTimeout(function () {
-                that.$score.animate({
+                elem.animate({
                     "background-color": "white",
                     "border-color": "white"
                 }, 100);
@@ -91,7 +109,7 @@ var GradeUI = Backbone.View.extend({
     },
 
     assignNoCredit: function () {
-        this.model.save({"manual_score": 0});
+        this.model.save({"manual_score": 0, "extra_credit": 0});
         this.$score.select();
         this.$score.focus();
     }
diff --git a/nbgrader/server_extensions/formgrader/templates/formgrade.tpl b/nbgrader/server_extensions/formgrader/templates/formgrade.tpl
index 292774186..c917ab7c9 100644
--- a/nbgrader/server_extensions/formgrader/templates/formgrade.tpl
+++ b/nbgrader/server_extensions/formgrader/templates/formgrade.tpl
@@ -79,6 +79,9 @@ window.MathJax = {
     <span>
       <input class="score tabbable" id="{{ cell.metadata.nbgrader.grade_id }}" style="width: 4em;" type="number" /> / {{ cell.metadata.nbgrader.points | float | round(2) }}
     </span>
+    <span style="margin-left: 1em;">
+      + <input class="extra-credit tabbable" id="{{ cell.metadata.nbgrader.grade_id }}_extra_credit" style="width: 3em;" type="number" /> (extra credit)
+    </span>
   </div>
 {%- endmacro %}
 
diff --git a/nbgrader/tests/api/test_models.py b/nbgrader/tests/api/test_models.py
index 70240fe83..790fc2c15 100644
--- a/nbgrader/tests/api/test_models.py
+++ b/nbgrader/tests/api/test_models.py
@@ -851,6 +851,49 @@ def test_query_code_score_manualgraded(submissions):
     assert [1.5, 3] == sorted(x[1] for x in db.query(api.SubmittedNotebook.id, api.SubmittedNotebook.code_score).all())
     assert [1.5, 3] == sorted(x[1] for x in db.query(api.SubmittedAssignment.id, api.SubmittedAssignment.code_score).all())
 
+def test_query_auto_score_extra_credit(submissions):
+    db, grades, _ = submissions
+
+    grades[0].auto_score = 10
+    grades[1].auto_score = 0
+    grades[2].auto_score = 5
+    grades[3].auto_score = 2.5
+
+    grades[0].extra_credit = 0.5
+    grades[1].extra_credit = 0
+    grades[2].extra_credit = 2.3
+    grades[3].extra_credit = 1.1
+    db.commit()
+
+    assert sorted(x[0] for x in db.query(api.Grade.score).all()) == [0, 3.6, 7.3, 10.5]
+    assert sorted(x[1] for x in db.query(api.SubmittedNotebook.id, api.SubmittedNotebook.score).all()) == [10.5, 10.9]
+    assert sorted(x[1] for x in db.query(api.SubmittedAssignment.id, api.SubmittedAssignment.score).all()) == [10.5, 10.9]
+    assert sorted(x[1] for x in db.query(api.Student.id, api.Student.score).all()) == [10.5, 10.9]
+
+def test_query_manual_score_extra_credit(submissions):
+    db, grades, _ = submissions
+
+    grades[0].auto_score = 10
+    grades[1].auto_score = 0
+    grades[2].auto_score = 5
+    grades[3].auto_score = 2.5
+
+    grades[0].manual_score = 4
+    grades[1].manual_score = 1.5
+    grades[2].manual_score = 9
+    grades[3].manual_score = 3
+
+    grades[0].extra_credit = 0.5
+    grades[1].extra_credit = 0
+    grades[2].extra_credit = 2.3
+    grades[3].extra_credit = 1.1
+    db.commit()
+
+    assert sorted(x[0] for x in db.query(api.Grade.score).all()) == [1.5, 4.1, 4.5, 11.3]
+    assert sorted(x[1] for x in db.query(api.SubmittedNotebook.id, api.SubmittedNotebook.score).all()) == [6, 15.4]
+    assert sorted(x[1] for x in db.query(api.SubmittedAssignment.id, api.SubmittedAssignment.score).all()) == [6, 15.4]
+    assert sorted(x[1] for x in db.query(api.Student.id, api.Student.score).all()) == [6, 15.4]
+
 def test_query_num_submissions(submissions):
     db = submissions[0]
 
@@ -1187,7 +1230,7 @@ def test_grade_to_dict(submissions):
         assert set(gd.keys()) == {
             'id', 'name', 'notebook', 'assignment', 'student', 'auto_score',
             'manual_score', 'max_score', 'needs_manual_grade', 'failed_tests',
-            'cell_type'}
+            'cell_type', 'extra_credit'}
 
         assert gd['id'] == g.id
         assert gd['name'] == g.name
@@ -1196,6 +1239,7 @@ def test_grade_to_dict(submissions):
         assert gd['student'] == g.student.id
         assert gd['auto_score'] is None
         assert gd['manual_score'] is None
+        assert gd['extra_credit'] is None
         assert gd['needs_manual_grade']
         assert not gd['failed_tests']
         assert gd['cell_type'] == g.cell_type
diff --git a/nbgrader/tests/nbextensions/formgrade_utils.py b/nbgrader/tests/nbextensions/formgrade_utils.py
index 36ecb9ea9..f25401f24 100644
--- a/nbgrader/tests/nbextensions/formgrade_utils.py
+++ b/nbgrader/tests/nbextensions/formgrade_utils.py
@@ -137,6 +137,10 @@ def _get_score_box(browser, index):
     return browser.find_elements_by_css_selector(".score")[index]
 
 
+def _get_extra_credit_box(browser, index):
+    return browser.find_elements_by_css_selector(".extra-credit")[index]
+
+
 def _save_comment(browser, index):
     _send_keys_to_body(browser, Keys.ESCAPE)
     glyph = browser.find_elements_by_css_selector(".comment-saved")[index]
diff --git a/nbgrader/tests/nbextensions/test_formgrader.py b/nbgrader/tests/nbextensions/test_formgrader.py
index 1937b0a2d..eeeec21a1 100644
--- a/nbgrader/tests/nbextensions/test_formgrader.py
+++ b/nbgrader/tests/nbextensions/test_formgrader.py
@@ -441,45 +441,75 @@ def test_tabbing(browser, port, gradebook):
     assert utils._get_active_element(browser) == utils._get_score_box(browser, 0)
     assert utils._get_index(browser) == 2
 
+    # tab to the next and check that the first extra credit is selected
+    utils._send_keys_to_body(browser, Keys.TAB)
+    assert utils._get_active_element(browser) == utils._get_extra_credit_box(browser, 0)
+    assert utils._get_index(browser) == 3
+
     # tab to the next and check that the second points is selected
     utils._send_keys_to_body(browser, Keys.TAB)
     assert utils._get_active_element(browser) == utils._get_score_box(browser, 1)
-    assert utils._get_index(browser) == 3
+    assert utils._get_index(browser) == 4
+
+    # tab to the next and check that the second extra credit is selected
+    utils._send_keys_to_body(browser, Keys.TAB)
+    assert utils._get_active_element(browser) == utils._get_extra_credit_box(browser, 1)
+    assert utils._get_index(browser) == 5
 
     # tab to the next and check that the second comment is selected
     utils._send_keys_to_body(browser, Keys.TAB)
     assert utils._get_active_element(browser) == utils._get_comment_box(browser, 1)
-    assert utils._get_index(browser) == 4
+    assert utils._get_index(browser) == 6
 
     # tab to the next and check that the third points is selected
     utils._send_keys_to_body(browser, Keys.TAB)
     assert utils._get_active_element(browser) == utils._get_score_box(browser, 2)
-    assert utils._get_index(browser) == 5
+    assert utils._get_index(browser) == 7
+
+    # tab to the next and check that the third extra credit is selected
+    utils._send_keys_to_body(browser, Keys.TAB)
+    assert utils._get_active_element(browser) == utils._get_extra_credit_box(browser, 2)
+    assert utils._get_index(browser) == 8
 
     # tab to the next and check that the fourth points is selected
     utils._send_keys_to_body(browser, Keys.TAB)
     assert utils._get_active_element(browser) == utils._get_score_box(browser, 3)
-    assert utils._get_index(browser) == 6
+    assert utils._get_index(browser) == 9
+
+    # tab to the next and check that the fourth extra credit is selected
+    utils._send_keys_to_body(browser, Keys.TAB)
+    assert utils._get_active_element(browser) == utils._get_extra_credit_box(browser, 3)
+    assert utils._get_index(browser) == 10
 
     # tab to the next and check that the fifth points is selected
     utils._send_keys_to_body(browser, Keys.TAB)
     assert utils._get_active_element(browser) == utils._get_score_box(browser, 4)
-    assert utils._get_index(browser) == 7
+    assert utils._get_index(browser) == 11
+
+    # tab to the next and check that the fifth extra credit is selected
+    utils._send_keys_to_body(browser, Keys.TAB)
+    assert utils._get_active_element(browser) == utils._get_extra_credit_box(browser, 4)
+    assert utils._get_index(browser) == 12
 
     # tab to the next and check that the third comment is selected
     utils._send_keys_to_body(browser, Keys.TAB)
     assert utils._get_active_element(browser) == utils._get_comment_box(browser, 2)
-    assert utils._get_index(browser) == 8
+    assert utils._get_index(browser) == 13
 
     # tab to the next and check that the sixth points is selected
     utils._send_keys_to_body(browser, Keys.TAB)
     assert utils._get_active_element(browser) == utils._get_score_box(browser, 5)
-    assert utils._get_index(browser) == 9
+    assert utils._get_index(browser) == 14
+
+    # tab to the next and check that the sixth extra credit is selected
+    utils._send_keys_to_body(browser, Keys.TAB)
+    assert utils._get_active_element(browser) == utils._get_extra_credit_box(browser, 5)
+    assert utils._get_index(browser) == 15
 
     # tab to the next and check that the fourth comment is selected
     utils._send_keys_to_body(browser, Keys.TAB)
     assert utils._get_active_element(browser) == utils._get_comment_box(browser, 3)
-    assert utils._get_index(browser) == 10
+    assert utils._get_index(browser) == 16
 
     # tab to the next and check that the next arrow is selected
     utils._send_keys_to_body(browser, Keys.TAB)
@@ -565,6 +595,37 @@ def test_save_score(browser, port, gradebook, index):
         assert "needs_manual_grade" in elem.get_attribute("class").split(" ")
 
 
+@pytest.mark.nbextensions
+@pytest.mark.parametrize("index", range(6))
+def test_save_extra_credit(browser, port, gradebook, index):
+    utils._load_formgrade(browser, port, gradebook)
+    elem = utils._get_extra_credit_box(browser, index)
+
+    if elem.get_attribute("value") != "":
+        elem.click()
+        elem.clear()
+        utils._save_score(browser, index)
+        utils._load_formgrade(browser, port, gradebook)
+        elem = utils._get_extra_credit_box(browser, index)
+        assert elem.get_attribute("value") == ""
+
+    # set the grade
+    elem.click()
+    elem.send_keys("{}".format((index + 1) / 10.0))
+    utils._save_score(browser, index)
+    utils._load_formgrade(browser, port, gradebook)
+    elem = utils._get_extra_credit_box(browser, index)
+    assert elem.get_attribute("value") == "{}".format((index + 1) / 10.0)
+
+    # clear the grade
+    elem.click()
+    elem.clear()
+    utils._save_score(browser, index)
+    utils._load_formgrade(browser, port, gradebook)
+    elem = utils._get_extra_credit_box(browser, index)
+    assert elem.get_attribute("value") == ""
+
+
 @pytest.mark.nbextensions
 def test_same_part_navigation(browser, port, gradebook):
     problem = gradebook.find_notebook("Problem 1", "Problem Set 1")
@@ -578,24 +639,24 @@ def test_same_part_navigation(browser, port, gradebook):
     # Click the second comment box and navigate to the next submission
     utils._get_comment_box(browser, 1).click()
     utils._send_keys_to_body(browser, Keys.CONTROL, ".")
-    utils._wait_for_formgrader(browser, port, "submissions/{}/?index=4".format(submissions[1].id))
+    utils._wait_for_formgrader(browser, port, "submissions/{}/?index=6".format(submissions[1].id))
     assert utils._get_active_element(browser) == utils._get_comment_box(browser, 1)
 
     # Click the third score box and navigate to the previous submission
     utils._get_score_box(browser, 2).click()
     utils._send_keys_to_body(browser, Keys.CONTROL, ",")
-    utils._wait_for_formgrader(browser, port, "submissions/{}/?index=5".format(submissions[0].id))
+    utils._wait_for_formgrader(browser, port, "submissions/{}/?index=7".format(submissions[0].id))
     assert utils._get_active_element(browser) == utils._get_score_box(browser, 2)
 
     # Click the third comment box and navigate to the next submission
     utils._get_comment_box(browser, 2).click()
     utils._send_keys_to_body(browser, Keys.CONTROL, ".")
-    utils._wait_for_formgrader(browser, port, "submissions/{}/?index=7".format(submissions[1].id))
+    utils._wait_for_formgrader(browser, port, "submissions/{}/?index=11".format(submissions[1].id))
     assert utils._get_active_element(browser) == utils._get_score_box(browser, 4)
 
     # Navigate to the previous submission
     utils._send_keys_to_body(browser, Keys.CONTROL, ",")
-    utils._wait_for_formgrader(browser, port, "submissions/{}/?index=7".format(submissions[0].id))
+    utils._wait_for_formgrader(browser, port, "submissions/{}/?index=11".format(submissions[0].id))
     assert utils._get_active_element(browser) == utils._get_score_box(browser, 4)