diff --git a/taxcalc/calculator.py b/taxcalc/calculator.py
index d0b92a598..14129d585 100644
--- a/taxcalc/calculator.py
+++ b/taxcalc/calculator.py
@@ -105,7 +105,7 @@ def __init__(self, policy=None, records=None, verbose=False,
         if self.__policy.current_year < self.__records.data_year:
             self.__policy.set_year(self.__records.data_year)
         if consumption is None:
-            self.__consumption = Consumption()
+            self.__consumption = Consumption(policy.nyrs)
         elif isinstance(consumption, Consumption):
             self.__consumption = copy.deepcopy(consumption)
         else:
diff --git a/taxcalc/consumption.py b/taxcalc/consumption.py
index 0be9ea904..bfc12b4e1 100644
--- a/taxcalc/consumption.py
+++ b/taxcalc/consumption.py
@@ -28,14 +28,16 @@ class instance: Consumption
     """
 
     JSON_START_YEAR = Policy.JSON_START_YEAR
-    DEFAULT_NUM_YEARS = Policy.DEFAULT_NUM_YEARS
+    NUM_YEARS = Policy.NUM_YEARS
     DEFAULTS_FILE_NAME = 'consumption.json'
     DEFAULTS_FILE_PATH = os.path.abspath(os.path.dirname(__file__))
 
-    def __init__(self):
+    def __init__(self, nyrs=NUM_YEARS):
+        # put JSON contents of DEFAULTS_FILE_NAME into self._vals dictionary
         super().__init__()
+        print("Consumption num years = ", nyrs)
         self.initialize(Consumption.JSON_START_YEAR,
-                        Consumption.DEFAULT_NUM_YEARS)
+                        nyrs)
 
     @staticmethod
     def read_json_update(obj):
diff --git a/taxcalc/growdiff.py b/taxcalc/growdiff.py
index e4cc4ac9e..8f45d6727 100644
--- a/taxcalc/growdiff.py
+++ b/taxcalc/growdiff.py
@@ -28,14 +28,18 @@ class instance: GrowDiff
     """
 
     JSON_START_YEAR = Policy.JSON_START_YEAR
-    DEFAULT_NUM_YEARS = Policy.DEFAULT_NUM_YEARS
+    NUM_YEARS = Policy.NUM_YEARS
     DEFAULTS_FILE_NAME = 'growdiff.json'
     DEFAULTS_FILE_PATH = os.path.abspath(os.path.dirname(__file__))
 
-    def __init__(self):
+    def __init__(self, nyrs=NUM_YEARS):
+        # Update defaults to user defined budget window
+        self.defaults = super().get_defaults()
+        label = self.defaults["schema"]["labels"]["year"]
+        label["validators"]["range"]["max"] = GrowDiff.JSON_START_YEAR + nyrs - 1
         super().__init__()
         self.initialize(GrowDiff.JSON_START_YEAR,
-                        GrowDiff.DEFAULT_NUM_YEARS)
+                        nyrs)
 
     @staticmethod
     def read_json_update(obj, topkey):
diff --git a/taxcalc/parameters.py b/taxcalc/parameters.py
index d3eac686f..f4e3d1b85 100644
--- a/taxcalc/parameters.py
+++ b/taxcalc/parameters.py
@@ -102,19 +102,12 @@ def __init__(self, start_year=None, num_years=None, last_known_year=None,
                 self.DEFAULTS_FILE_NAME
             )
 
-        # def get_defaults(self):
-        """
-        Method to allow for the defaults to be modified.
-        """
-        label = self.default["schema"]["labels"]["year"]
-        label["validators"]["range"]["max"] = 2074#year_to_extend
-        return self.defaults
-
+        last_budget_year = start_year + num_years - 1
         if last_known_year is None:
             self._last_known_year = start_year
         else:
             assert last_known_year >= start_year
-            assert last_known_year <= self.LAST_BUDGET_YEAR
+            assert last_known_year <= last_budget_year
             self._last_known_year = last_known_year
 
         self._removed_params = removed or self.REMOVED_PARAMS
@@ -129,8 +122,17 @@ def __init__(self, start_year=None, num_years=None, last_known_year=None,
             kwargs["initial_state"] = {
                 "year": start_year or self.JSON_START_YEAR
             }
+        # Update defaults to user defined budget window
+        self.defaults = super().get_defaults()
+        label = self.defaults["schema"]["labels"]["year"]
+        label["validators"]["range"]["max"] = start_year + num_years - 1
         super().__init__(**kwargs)
 
+    # def get_defaults(self):
+    #     label = self.defaults["schema"]["labels"]["year"]
+    #     label["validators"]["range"]["max"] = 2074
+    #     return self.defaults
+
     def adjust(
         self, params_or_path, print_warnings=True, raise_errors=True, **kwargs
     ):
@@ -827,4 +829,4 @@ def is_paramtools_format(params: Union[TaxcalcReform, ParamToolsAdjustment]):
         else:
             # Not doing a specific check to see if the value is a list
             # since it could be a list or just a scalar value.
-            return True
+            return True
\ No newline at end of file
diff --git a/taxcalc/policy.py b/taxcalc/policy.py
index 435f3c3c1..4a8279417 100644
--- a/taxcalc/policy.py
+++ b/taxcalc/policy.py
@@ -40,9 +40,8 @@ class instance: Policy
     JSON_START_YEAR = 2013  # remains the same unless earlier data added
     LAST_KNOWN_YEAR = 2025  # last year for which indexed param vals are known
     # should increase LAST_KNOWN_YEAR by one every calendar year
-    LAST_BUDGET_YEAR = 2074  # last extrapolation year
-    # should increase LAST_BUDGET_YEAR by one every calendar year
-    DEFAULT_NUM_YEARS = LAST_BUDGET_YEAR - JSON_START_YEAR + 1
+    DEFAULT_LAST_BUDGET_YEAR = 2034  # last extrapolation year
+    NUM_YEARS = DEFAULT_LAST_BUDGET_YEAR - JSON_START_YEAR + 1
 
     # NOTE: the following three data structures use internal parameter names:
     # (1) specify which Policy parameters have been removed or renamed
@@ -81,11 +80,9 @@ class instance: Policy
     # (3) specify which Policy parameters are wage (rather than price) indexed
     WAGE_INDEXED_PARAMS = ['SS_Earnings_c', 'SS_Earnings_thd']
 
-    def __init__(self, gfactors=None, **kwargs):
+    def __init__(self, gfactors=None, last_budget_year=DEFAULT_LAST_BUDGET_YEAR,  **kwargs):
         # put JSON contents of DEFAULTS_FILE_NAME into self._vals dictionary
         super().__init__()
-        # print(self.__dict__)
-        # self._vals["schema"]["labels"]["year"]["validators"]["range"]["max"] = 2074
         # handle gfactors argument
         if gfactors is None:
             self._gfactors = GrowFactors()
@@ -95,27 +92,13 @@ def __init__(self, gfactors=None, **kwargs):
             raise ValueError('gfactors is not None or a GrowFactors instance')
         # read default parameters and initialize
         syr = Policy.JSON_START_YEAR
-        nyrs = Policy.DEFAULT_NUM_YEARS
+        self.nyrs = last_budget_year - syr + 1
         self._inflation_rates = None
         self._wage_growth_rates = None
-        self.initialize(syr, nyrs, Policy.LAST_KNOWN_YEAR,
+        self.initialize(syr, self.nyrs, Policy.LAST_KNOWN_YEAR,
                         Policy.REMOVED_PARAMS,
                         Policy.REDEFINED_PARAMS,
                         Policy.WAGE_INDEXED_PARAMS, **kwargs)
-        print("Defaults = ", self.defaults)
-        # json_params = self.get_defaults()
-        # label = json_params["schema"]["labels"]["year"]
-        # label["validators"]["range"]["max"] = 2074
-        #         return self.defaults
-        # json_params["schema"]["labels"]["year"]["validators"]["range"]["max"] = 2074
-        # self.defaults = json_params
-        self.initialize(syr, nyrs, Policy.LAST_KNOWN_YEAR,
-                        Policy.REMOVED_PARAMS,
-                        Policy.REDEFINED_PARAMS,
-                        Policy.WAGE_INDEXED_PARAMS, **kwargs)
-        # quit()
-        print("Num years = ", nyrs)
-        # self.defaults = self.get_defaults()
 
     @staticmethod
     def tmd_constructor(growfactors_path):  # pragma: no cover
@@ -191,4 +174,4 @@ def set_rates(self):
 
         self._wage_growth_rates = self._gfactors.wage_growth_rates(
             self.start_year, self.end_year
-        )
+        )
\ No newline at end of file