diff --git a/lib/standard/lsp/routes.rb b/lib/standard/lsp/routes.rb
index ca07c202..f87e386a 100644
--- a/lib/standard/lsp/routes.rb
+++ b/lib/standard/lsp/routes.rb
@@ -181,7 +181,7 @@ def diagnostic(file_uri, text)
             message: msg,
             range: {
               start: {character: loc[:start_column] - 1, line: loc[:start_line] - 1},
-              end: {character: loc[:last_column] - 1, line: loc[:last_line] - 1}
+              end: {character: loc[:last_column], line: loc[:last_line] - 1}
             },
             severity: severity,
             source: "standard"
diff --git a/test/standard/runners/lsp_test.rb b/test/standard/runners/lsp_test.rb
index 35366a80..98833d0e 100644
--- a/test/standard/runners/lsp_test.rb
+++ b/test/standard/runners/lsp_test.rb
@@ -45,17 +45,17 @@ def test_did_open
         diagnostics: [
           {code: "Layout/ArrayAlignment",
            message: "Use one level of indentation for elements following the first line of a multi-line array.",
-           range: {start: {character: 3, line: 2}, end: {character: 3, line: 2}},
+           range: {start: {character: 3, line: 2}, end: {character: 4, line: 2}},
            severity: 3,
            source: "standard"},
           {code: "Layout/ExtraSpacing",
            message: "Unnecessary spacing detected.",
-           range: {start: {character: 4, line: 2}, end: {character: 4, line: 2}},
+           range: {start: {character: 4, line: 2}, end: {character: 5, line: 2}},
            severity: 3,
            source: "standard"},
           {code: "Layout/SpaceInsideArrayLiteralBrackets",
            message: "Do not use space inside array brackets.",
-           range: {start: {character: 4, line: 2}, end: {character: 5, line: 2}},
+           range: {start: {character: 4, line: 2}, end: {character: 6, line: 2}},
            severity: 3,
            source: "standard"}
         ],