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":
Father: Robert BAKER
(1830 Elmswell, Suffolk, England - Jun 1909 Stow, Suffolk, England)
Mother: Elizabeth FAIERS
(Abt 1839 Elmswell, Suffolk, England - Jul 1896 Stow, Suffolk, England)
Robert James BAKER
(Jun 1865 Elmswell, Suffolk, England - 17 May 1937 Bury, Suffolk, England)
Mary Ann Ada BALLS
(Abt 1873 Saint Horkesley, Essex, England - 12 Dec 1914 Rattlesden, Suffolk, England)
└─Cecil William BAKER
(26 Sep 1901 Quetta, India - 4 Apr 1984 Norwich, Norfolk, England)
Hattie Alice MESSENGER
(20 Nov 1907 Maldon, Essex, England - Aug 2000 Norwich, Norfolk, England)
1865 - 1937 (~ 71 years)
Mary Ann Ada BALLS 
(Abt 1873 Saint Horkesley, Essex, England - 12 Dec 1914 Rattlesden, Suffolk, England)