The paper length is not relevant since the chart flows from one page to the next.
Mobile
in.
mm
Portrait
2.75
70
For smart phones, not for printing
Landscape
5.5
140
For smart phones, not for printing
USA & Canada
in.
mm
Letter Portrait
8.5
216
Also Legal Portrait
Letter Landscape
11
279
Legal Landscape
14
356
Also Ledger Portrait
Ledger Landscape
17
432
International
in.
mm
A5 Portrait
5.82
148
A4 Portrait
8.25
210
Also A5 Landscape
A4 Landscape
11.71
297
Also A3 Landscape
A3 Landscape
16.54
420
The Text+ programs assume that the right and left margins are each about 25mm (1/2 inch) wide.
On the Format for Printing page, differences in page margins can be accommodated by the "fudge factor":
George JOHNSON
(25 Mar 1852 Fremantle, Western Australia, Australia - 14 Feb 1927)
Ellen Maria TROTT (13 May 1857 Bunbury, Western Australia, Australia - 1 Feb 1924 Wellington, Western Australia, Australia)(m. 1880)
└─Alfred Aubrey Holton JOHNSON (5 Dec 1889 Fremantle, Western Australia, Australia - 9 Sep 1969 Perth, Western Australia, Australia)
Edwena Ellen Delores NEWPORT (27 Sep 1893 York, Western Australia, Australia - 7 Sep 1969 North Perth, Western Australia, Australia)(m. 25 Jun 1913 Northam, Western Australia, Australia)
1852 - 1927 (74 years)
Ellen Maria TROTT 
(13 May 1857 Bunbury, Western Australia, Australia -