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":
Richard HAYWARD
(1813 Surrey, England - 1 Jun 1884 Croydon, Surrey, England)
Mary UNKNOWN
(Abt 1830 Surrey, England - DECEASED)
└─Emma HAYWARD
(1849 Croydon, Surrey, England - 6 Jan 1914 Footscray, Victoria, Australia)
Alexander RILEY
(12 Mar 1840 Carlton, Yorkshire, England - 5 Nov 1883 Smythesdale, Victoria, Australia)
└─John Robert RILEY
(1875 Haddon, Victoria, Australia - 22 May 1947 Geelong, Victoria, Australia)
Annie WATSON
(1880 Pointnepean, Victoria, Australia - 27 May 1948 Melbourne, Victoria, Australia)
└─Robert Watson RILEY
(7 May 1911 Point Nepean, Victoria, Australia - 6 Sep 1987 Malvern, Victoria, Australia)
1813 - 1884 (71 years)
Alexander RILEY 
(12 Mar 1840 Carlton, Yorkshire, England - 5 Nov 1883 Smythesdale, Victoria, Australia)