diff --git a/geomagio/Util.py b/geomagio/Util.py
index ee2cff6a011f58cd7a77d38e43b80ef5650c0b83..a72f6a05bd8fd2fe826e6f1d80a7b7494eb833d5 100644
--- a/geomagio/Util.py
+++ b/geomagio/Util.py
@@ -1,5 +1,6 @@
 import urllib2
 import numpy
+import os
 from obspy.core import Stats, Trace
 
 
@@ -22,6 +23,86 @@ class ObjectView(object):
         return str(self.__dict__)
 
 
+def get_file_from_url(url, createParentDirectory=False):
+    """Get a file for writing.
+
+    Ensures parent directory exists.
+
+    Parameters
+    ----------
+    url : str
+        path to file
+    createParentDirectory : bool
+        whether to create parent directory if it does not exist.
+        useful when preparing to write to the returned file.
+
+    Returns
+    -------
+    str
+        path to file without file:// prefix
+
+    Raises
+    ------
+    Exception
+        if url does not start with file://
+    """
+    if not url.startswith('file://'):
+        raise Exception('Only file urls are supported by get_file_from_url')
+    filename = url.replace('file://', '')
+    if createParentDirectory:
+        parent = os.path.dirname(filename)
+        if not os.path.exists(parent):
+            os.makedirs(parent)
+    return filename
+
+
+def get_intervals(starttime, endtime, size=86400, align=True, trim=False):
+    """Divide an interval into smaller intervals.
+
+    Divides the interval [starttime, endtime] into chunks.
+
+    Parameters
+    ----------
+    starttime : obspy.core.UTCDateTime
+        start of time interval to divide
+    endtime : obspy.core.UTCDateTime
+        end of time interval to divide
+    size : int
+        size of each interval in seconds.
+    align : bool
+        align intervals to unix epoch.
+        (works best when size evenly divides a day)
+    trim : bool
+        whether to trim first/last interval to starttime and endtime.
+
+    Returns
+    -------
+    list<dict>
+        each dictionary has the keys "starttime" and "endtime"
+        which represent [intervalstart, intervalend).
+    """
+    if align:
+        # align based on size
+        time = starttime - (starttime.timestamp % size)
+    else:
+        time = starttime
+    intervals = []
+    while time < endtime:
+        start = time
+        time = time + size
+        end = time
+        if trim:
+            if start < starttime:
+                start = starttime
+            if end > endtime:
+                end = endtime
+        intervals.append({
+            'start': start,
+            'end': end
+        })
+    return intervals
+
+
 def read_url(url):
     """Open and read url contents.
 
diff --git a/test/Util_test.py b/test/Util_test.py
new file mode 100644
index 0000000000000000000000000000000000000000..01618de6a0473e0246a3e007c3bc0b5a0b287fe3
--- /dev/null
+++ b/test/Util_test.py
@@ -0,0 +1,66 @@
+#! /usr/bin/env python
+import os.path
+import shutil
+from nose.tools import assert_equals, assert_false
+from geomagio import Util
+from obspy.core import UTCDateTime
+
+
+def test_get_file_for_url__throws_exception():
+    """Util_test.test_get_file_for_url__throws_exception()
+    """
+    # throws exception for non "file://" urls
+    try:
+        Util.get_file_from_url('http://someserver/path')
+        assert_false('expected exception')
+    except Exception:
+        pass
+
+
+def test_get_file_for_url__parses_file_urls():
+    """Util_test.test_get_file_for_url__parses_file_urls()
+    """
+    # parses file urls
+    f = Util.get_file_from_url('file://./somefile')
+    assert_equals(f, './somefile')
+
+
+def test_get_file_for_url__creates_directories():
+    """Util_test.test_get_file_for_url__creates_directories()
+    """
+    # creates directories if requested
+    if os.path.isdir('/tmp/_geomag_algorithms_test_'):
+        shutil.rmtree('/tmp/_geomag_algorithms_test_')
+    f = Util.get_file_from_url('file:///tmp/_geomag_algorithms_test_/somefile',
+            createParentDirectory=True)
+    if not os.path.isdir('/tmp/_geomag_algorithms_test_'):
+        assert_false('directory not created')
+    shutil.rmtree('/tmp/_geomag_algorithms_test_')
+    assert_equals(f, '/tmp/_geomag_algorithms_test_/somefile')
+
+
+def test_get_interval__defaults():
+    """Util_test.test_get_interval()
+    """
+    starttime = UTCDateTime('2015-01-01T00:00:00Z')
+    endtime = UTCDateTime('2015-02-01T00:00:00Z')
+    intervals = Util.get_intervals(starttime, endtime)
+    assert_equals(len(intervals), 31)
+
+
+def test_get_interval__custom_size():
+    """Util_test.test_get_interval__custom_size()
+    """
+    starttime = UTCDateTime('2015-01-01T00:00:00Z')
+    endtime = UTCDateTime('2015-01-02T00:00:00Z')
+    intervals = Util.get_intervals(starttime, endtime, size=3600)
+    assert_equals(len(intervals), 24)
+
+
+def test_get_interval__trim():
+    """Util_test.test_get_interval__trim()
+    """
+    starttime = UTCDateTime('2015-01-01T01:00:00Z')
+    endtime = UTCDateTime('2015-01-02T00:00:00Z')
+    intervals = Util.get_intervals(starttime, endtime, trim=True)
+    assert_equals(intervals[0]['start'], starttime)