diff --git a/src/pycalver/v1version.py b/src/pycalver/v1version.py
index dac43a0..af1af25 100644
--- a/src/pycalver/v1version.py
+++ b/src/pycalver/v1version.py
@@ -103,7 +103,10 @@ def _parse_field_values(field_values: FieldValues) -> version.V1VersionInfo:
     bid = fvals['bid'] if 'bid' in fvals else "0001"
 
     year = int(fvals['year']) if 'year' in fvals else None
-    doy  = int(fvals['doy' ]) if 'doy' in fvals else None
+    if year is not None and year < 100:
+        year += 2000
+
+    doy = int(fvals['doy']) if 'doy' in fvals else None
 
     month: typ.Optional[int]
     dom  : typ.Optional[int]
@@ -211,6 +214,10 @@ def _parse_version_info(pattern_groups: PatternGroups) -> version.V1VersionInfo:
     >>> (vnfo.year, vnfo.month, vnfo.quarter, vnfo.bid, vnfo.tag)
     (2018, 11, 4, '0099', 'final')
 
+    >>> vnfo = _parse_version_info({'year': "18", 'month': "11"})
+    >>> (vnfo.year, vnfo.month, vnfo.quarter)
+    (2018, 11, 4)
+
     >>> vnfo = _parse_version_info({'year': "2018", 'doy': "11", 'bid': "099", 'tag': "b"})
     >>> (vnfo.year, vnfo.month, vnfo.dom, vnfo.bid, vnfo.tag)
     (2018, 1, 11, '099', 'beta')
diff --git a/src/pycalver/v2version.py b/src/pycalver/v2version.py
index 4ee941d..f3a85cd 100644
--- a/src/pycalver/v2version.py
+++ b/src/pycalver/v2version.py
@@ -109,6 +109,10 @@ def _parse_version_info(field_values: FieldValues) -> version.V2VersionInfo:
     >>> (vinfo.year_y, vinfo.month, vinfo.quarter, vinfo.bid, vinfo.tag)
     (2018, 11, 4, '0099', 'final')
 
+    >>> vinfo = _parse_version_info({'year_y': "18", 'month': "11"})
+    >>> (vinfo.year_y, vinfo.month, vinfo.quarter)
+    (2018, 11, 4)
+
     >>> vinfo = _parse_version_info({'year_y': "2018", 'doy': "11", 'bid': "099", 'tag': "beta"})
     >>> (vinfo.year_y, vinfo.month, vinfo.dom, vinfo.doy, vinfo.bid, vinfo.tag)
     (2018, 1, 11, 11, '099', 'beta')
@@ -162,6 +166,11 @@ def _parse_version_info(field_values: FieldValues) -> version.V2VersionInfo:
     year_y: MaybeInt = int(fvals['year_y']) if 'year_y' in fvals else None
     year_g: MaybeInt = int(fvals['year_g']) if 'year_g' in fvals else None
 
+    if year_y is not None and year_y < 1000:
+        year_y += 2000
+    if year_g is not None and year_g < 1000:
+        year_g += 2000
+
     month: MaybeInt = int(fvals['month']) if 'month' in fvals else None
     doy  : MaybeInt = int(fvals['doy'  ]) if 'doy' in fvals else None
     dom  : MaybeInt = int(fvals['dom'  ]) if 'dom' in fvals else None