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: Thomas Henry STONE
(Bethnal Green, Middlesex, England;Mar 1856 - Jun 1911)
Mother: Elizabeth CAPES
(Apr 1859 Bethnal Green, Middlesex, England - DECEASED)
Cecil John STONE
(25 Oct 1886 Bethnal Green, Middlesex, England - 1 Sep 1941 Hackney, Middlesex, England)
Emily Agnes BARWICK
(30 Oct 1884 Bethnal Green, Middlesex, England - DECEASED)
(m. 27 Aug 1911 Bethnal Green, Middlesex, England)
├─Cecil Norman STONE
(18 Sep 1912 Bethnal Green, Middlesex, England - 17 Dec 1989 London, England)
└─Alfred Leonard STONE
(4 May 1914 Bethnal Green, Middlesex, England - 28 Oct 1994 Pembrokeshire, Wales)
Pamela M MAY
(Jun 1926 Cirencester, Gloucestershire, England - 2017)
(m. Oct 1950 Edmonton, Middlesex, England)
1886 - 1941 (54 years)
Emily Agnes BARWICK 
(30 Oct 1884 Bethnal Green, Middlesex, England - DECEASED)