diff --git a/Doc/library/json.rst b/Doc/library/json.rst
index 71020fd..400e2d2 100644
--- a/Doc/library/json.rst
+++ b/Doc/library/json.rst
@@ -103,7 +103,7 @@
         "json": "obj"
     }
     $ echo '{1.2:3.4}' | python -mjson.tool
-    Expecting property name enclosed in double quotes: line 1 column 1 (char 1)
+    Expecting property name enclosed in double quotes: line 1 column 2 (char 1)
 
 .. highlight:: python
 
diff --git a/Lib/json/__init__.py b/Lib/json/__init__.py
index d6a45d3..0be85da 100644
--- a/Lib/json/__init__.py
+++ b/Lib/json/__init__.py
@@ -95,7 +95,7 @@
         "json": "obj"
     }
     $ echo '{ 1.2:3.4}' | python -m json.tool
-    Expecting property name enclosed in double quotes: line 1 column 2 (char 2)
+    Expecting property name enclosed in double quotes: line 1 column 3 (char 2)
 """
 __version__ = '2.0.9'
 __all__ = [
diff --git a/Lib/json/decoder.py b/Lib/json/decoder.py
index 7e2c68c..dc8916c 100644
--- a/Lib/json/decoder.py
+++ b/Lib/json/decoder.py
@@ -27,7 +27,7 @@
 def linecol(doc, pos):
     lineno = doc.count('\n', 0, pos) + 1
     if lineno == 1:
-        colno = pos
+        colno = pos + 1
     else:
         colno = pos - doc.rindex('\n', 0, pos)
     return lineno, colno
diff --git a/Lib/json/tool.py b/Lib/json/tool.py
index fe47c52..fc5d749 100644
--- a/Lib/json/tool.py
+++ b/Lib/json/tool.py
@@ -7,7 +7,7 @@
         "json": "obj"
     }
     $ echo '{ 1.2:3.4}' | python -m json.tool
-    Expecting property name enclosed in double quotes: line 1 column 2 (char 2)
+    Expecting property name enclosed in double quotes: line 1 column 3 (char 2)
 
 """
 import sys
diff --git a/Misc/NEWS b/Misc/NEWS
index 2c88b61..0b619fb 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -208,6 +208,9 @@
 Library
 -------
 
+- Issue #17225: JSON decoder now counts columns in the first line starting
+  with 1, as in other lines.
+
 - Issue #7842: backported fix for py_compile.compile() syntax error handling.
 
 - Issue #13153: Tkinter functions now raise TclError instead of ValueError when