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":
Amelia COOPER
(3 Sep 1838 Slaugham, Sussex, England - 13 Feb 1876 Bermondsey, Surrey, England)
John Thomas YEO
(28 Nov 1841 Whitechapel, Middlesex, England - 21 Feb 1908 Southwark, Surrey, England)
└─Amelia Emma YEO
(4 Jul 1861 Bermondsey, Surrey, England - 23 Feb 1917 Walworth, Surrey, England)
Thomas Aloysius HOWARD
(Abt 1859 Galway, Ireland - 11 Jan 1908 Walworth, Surrey, England)
└─Charles HOWARD
(18 May 1896 Walworth, Surrey, England - 30 Nov 1977 Bickley, Kent, England)
Violet Mary Ann GILES
(Abt 17 Dec 1901 London, England - Nov 1982 Bromley, Kent, England)
└─Irene Violet HOWARD
(30 Jan 1923 Southwark, Surrey, England - 10 Jul 2006 Coventry, Warwickshire, England)
1838 - 1876 (37 years)
John Thomas YEO 
(28 Nov 1841 Whitechapel, Middlesex, England - 21 Feb 1908 Southwark, Surrey, England)