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":
Andrew Joseph FORREST
(May 1894 Cork, Ireland - 13 Nov 1944 Kalguddering, Western Australia, Australia)
Anastasia Elizabeth WILLIAMS (1 Aug 1892 Toodyay, Western Australia, Australia - 8 May 1986 Wongan Hills, Western Australia, Australia)(m. 1921 Fremantle, Western Australia, Australia)
└─Betty Patricia FORREST (20 Dec 1921 Goomalling, Western Australia, Australia - Jul 2020 Wongan Hills, Western Australia, Australia)
Alan James ELLIS (19 Apr 1920 Perth, Western Australia, Australia - 13 May 2004)
(m. 1941 Victoria Plains, Western Australia, Australia)
1894 - 1944 (~ 50 years)
Anastasia Elizabeth WILLIAMS 
(1 Aug 1892 Toodyay, Western Australia, Australia -