diff --git a/macdate.py b/macdate.py
new file mode 100755
index 0000000..9c8e903
--- /dev/null
+++ b/macdate.py
@@ -0,0 +1,63 @@
+#!/usr/bin/env python3
+
+import sys
+from datetime import datetime, timedelta
+
+
+# Copied from machfs MakeHFS
+def hfsdat(x):
+    if x.lower() == "now":
+        x = datetime.now().isoformat()
+
+    if len(x) == 8 and all(c in "0123456789ABCDEF" for c in x.upper()):
+        try:
+            return int(x, base=16)
+        except ValueError:
+            pass
+
+    epoch = "19040101000000"  # ISO8601 with the non-numerics stripped
+
+    # strip non-numerics and pad out using the epoch (cheeky)
+    stripped = "".join(c for c in x if c in "0123456789")
+    stripped = stripped[: len(epoch)] + epoch[len(stripped) :]
+
+    tformat = "%Y%m%d%H%M%S"
+
+    delta = datetime.strptime(stripped, tformat) - datetime.strptime(epoch, tformat)
+    delta = int(delta.total_seconds())
+
+    if not 0 <= delta <= 0xFFFFFFFF:
+        print("Warning: moving %r into the legacy MacOS date range (1904-2040)" % x)
+
+    delta = min(delta, 0xFFFFFFFF)
+    delta = max(delta, 0)
+
+    return delta
+
+
+# Copied from ExtractBinDates.py
+def macdatestr(srcint):
+    dt = datetime(1904, 1, 1) + timedelta(seconds=srcint)
+    st = dt.isoformat()
+    st = st.replace("T", " ")
+    return st
+
+
+def secs2date(secs):
+    print(f"${secs:08x} = {macdatestr(secs)}")
+
+
+def date2secs(date):
+    secs = hfsdat(date)
+    print(f"{macdatestr(secs)} = ${secs:08x}")
+
+
+for a in sys.argv[1:]:
+    if a.startswith("$"):
+        secs = int(a[1:], 16)
+        secs2date(secs)
+    elif a.startswith("0x"):
+        secs = int(a[2:], 16)
+        secs2date(secs)
+    else:
+        date2secs(a)