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":
Alfred William BELLAMY
(13 Jan 1866 Chagford, Devon, England - Dec 1952 Islington, Middlesex, England)
Annie BENNETT
(5 Apr 1883 Barton, Gloucestershire, England - Between Oct and Dec 1970 Haringey, Middlesex, England)
├─Alfred William BELLAMY
(5 Mar 1911 London, England - Mar 1980 Bournemouth, Dorset, England)
└─Reginald G BELLAMY
(Jan 1915 Islington, Middlesex, England - 28 Sep 2009 Barnet, Hertfordshire, England)
1866 - 1952 (86 years)
Annie BENNETT 
(5 Apr 1883 Barton, Gloucestershire, England - Between Oct and Dec 1970 Haringey, Middlesex, England)