diff --git a/Lib/test/certdata/make_ssl_certs.py b/Lib/test/certdata/make_ssl_certs.py
index 848ddd2c2ac14c..b6da13f3ec191c 100644
--- a/Lib/test/certdata/make_ssl_certs.py
+++ b/Lib/test/certdata/make_ssl_certs.py
@@ -1,6 +1,7 @@
 """Make the custom certificate and private key files used by test_ssl
 and friends."""
 
+import argparse
 import os
 import pprint
 import shutil
@@ -8,7 +9,8 @@
 from subprocess import *
 
 startdate = "20180829142316Z"
-enddate = "20371028142316Z"
+enddate_default = "20371028142316Z"
+days_default = "7000"
 
 req_template = """
     [ default ]
@@ -79,8 +81,8 @@
     default_startdate = {startdate}
     enddate = {enddate}
     default_enddate = {enddate}
-    default_days = 7000
-    default_crl_days = 7000
+    default_days = {days}
+    default_crl_days = {days}
     certificate = pycacert.pem
     private_key = pycakey.pem
     serial    = $dir/serial
@@ -117,7 +119,7 @@
 here = os.path.abspath(os.path.dirname(__file__))
 
 
-def make_cert_key(hostname, sign=False, extra_san='',
+def make_cert_key(cmdlineargs, hostname, sign=False, extra_san='',
                   ext='req_x509_extensions_full', key='rsa:3072'):
     print("creating cert for " + hostname)
     tempnames = []
@@ -130,11 +132,12 @@ def make_cert_key(hostname, sign=False, extra_san='',
             hostname=hostname,
             extra_san=extra_san,
             startdate=startdate,
-            enddate=enddate
+            enddate=cmdlineargs.enddate,
+            days=cmdlineargs.days
         )
         with open(req_file, 'w') as f:
             f.write(req)
-        args = ['req', '-new', '-nodes', '-days', '7000',
+        args = ['req', '-new', '-nodes', '-days', cmdlineargs.days,
                 '-newkey', key, '-keyout', key_file,
                 '-extensions', ext,
                 '-config', req_file]
@@ -175,7 +178,7 @@ def make_cert_key(hostname, sign=False, extra_san='',
 def unmake_ca():
     shutil.rmtree(TMP_CADIR)
 
-def make_ca():
+def make_ca(cmdlineargs):
     os.mkdir(TMP_CADIR)
     with open(os.path.join('cadir','index.txt'),'a+') as f:
         pass # empty file
@@ -192,7 +195,8 @@ def make_ca():
             hostname='our-ca-server',
             extra_san='',
             startdate=startdate,
-            enddate=enddate
+            enddate=cmdlineargs.enddate,
+            days=cmdlineargs.days
         )
         t.write(req)
         t.flush()
@@ -228,8 +232,13 @@ def write_cert_reference(path):
 
 
 if __name__ == '__main__':
+    parser = argparse.ArgumentParser(description='Make the custom certificate and private key files used by test_ssl and friends.')
+    parser.add_argument('--days', default=days_default)
+    parser.add_argument('--enddate', default=enddate_default)
+    cmdlineargs = parser.parse_args()
+
     os.chdir(here)
-    cert, key = make_cert_key('localhost', ext='req_x509_extensions_simple')
+    cert, key = make_cert_key(cmdlineargs, 'localhost', ext='req_x509_extensions_simple')
     with open('ssl_cert.pem', 'w') as f:
         f.write(cert)
     with open('ssl_key.pem', 'w') as f:
@@ -246,24 +255,24 @@ def write_cert_reference(path):
         f.write(cert)
 
     # For certificate matching tests
-    make_ca()
-    cert, key = make_cert_key('fakehostname', ext='req_x509_extensions_simple')
+    make_ca(cmdlineargs)
+    cert, key = make_cert_key(cmdlineargs, 'fakehostname', ext='req_x509_extensions_simple')
     with open('keycert2.pem', 'w') as f:
         f.write(key)
         f.write(cert)
 
-    cert, key = make_cert_key('localhost', sign=True)
+    cert, key = make_cert_key(cmdlineargs, 'localhost', sign=True)
     with open('keycert3.pem', 'w') as f:
         f.write(key)
         f.write(cert)
 
-    cert, key = make_cert_key('fakehostname', sign=True)
+    cert, key = make_cert_key(cmdlineargs, 'fakehostname', sign=True)
     with open('keycert4.pem', 'w') as f:
         f.write(key)
         f.write(cert)
 
     cert, key = make_cert_key(
-        'localhost-ecc', sign=True, key='param:secp384r1.pem'
+        cmdlineargs, 'localhost-ecc', sign=True, key='param:secp384r1.pem'
     )
     with open('keycertecc.pem', 'w') as f:
         f.write(key)
@@ -283,7 +292,7 @@ def write_cert_reference(path):
         'RID.1 = 1.2.3.4.5',
     ]
 
-    cert, key = make_cert_key('allsans', sign=True, extra_san='\n'.join(extra_san))
+    cert, key = make_cert_key(cmdlineargs, 'allsans', sign=True, extra_san='\n'.join(extra_san))
     with open('allsans.pem', 'w') as f:
         f.write(key)
         f.write(cert)
@@ -300,12 +309,12 @@ def write_cert_reference(path):
     ]
 
     # IDN SANS, signed
-    cert, key = make_cert_key('idnsans', sign=True, extra_san='\n'.join(extra_san))
+    cert, key = make_cert_key(cmdlineargs, 'idnsans', sign=True, extra_san='\n'.join(extra_san))
     with open('idnsans.pem', 'w') as f:
         f.write(key)
         f.write(cert)
 
-    cert, key = make_cert_key('nosan', sign=True, ext='req_x509_extensions_nosan')
+    cert, key = make_cert_key(cmdlineargs, 'nosan', sign=True, ext='req_x509_extensions_nosan')
     with open('nosan.pem', 'w') as f:
         f.write(key)
         f.write(cert)