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: John BRIDGER
(Lambeth, Surrey, England;Sep 1847 - Mar 1900)
Mother: Julia SULLIVAN
(Lambeth, Surrey, England;Jun 1847 - Between Jan and Mar 1910)
Ellen BRIDGER
(Abt 1868 London, England - Jul 1943 Uxbridge, Middlesex, England)
Arthur DAY
(1 May 1864 Minting, Lincolnshire, England - Between Oct and Dec 1924 St George's, Hanover Square, London, England)
└─Kate E DAY
(Abt 1897 - Jan 1965 St Pancras, Middlesex, England)
James William BALDOCK
(25 Jul 1898 London, England - Jul 1952 Stepney, Middlesex, England)
: └─Stanley JEFFREYS
(14 Sep 1938 London, England - 26 Oct 2021 Eastbourne, Sussex, England)
Abt 1868 - 1943 (~ 75 years)
Arthur DAY 
(1 May 1864 Minting, Lincolnshire, England - Between Oct and Dec 1924 St George's, Hanover Square, London, England)