The following pictures show n unit octagons packed inside the smallest known square (of side s).
1. 
s = 1 + √2 = 2.41421+
Trivial.
2. 
s = 2 + 3√2/2 = 4.12132+
Found by Jonathan Viquerat
in May 2026.
3.-4. 
s = 2 + 2√2 = 4.82842+
Trivial.
5. 
s = 3 + 2√2 = 5.82842+
Found by Jonathan Viquerat
in May 2026.
6. 
s = (11√2+17)/5 = 6.51126+
Found by Jonathan Viquerat
in May 2026.
7. 
s = (5√2+7)/2 = 7.03553+
Found by Jonathan Viquerat
in May 2026.
8.-9. 
s = 3 + 3√2 = 7.24264+
Trivial.
10. 
s = 4+3√2 = 8.24264+
Found by Jonathan Viquerat
in May 2026.
11. 
s = 8.57596+
Found by Jonathan Viquerat
in May 2026.
12. 
s = (23√2+38)/8 = 8.81586+
Found by Jonathan Viquerat
in May 2026.
13. 
s = 9.19909+
Found by Jonathan Viquerat
in May 2026.
14. 
s = (7√2+9)/2 = 9.44974+
Found by Jonathan Viquerat
in May 2026.
15.-16. 
s = 4 + 4√2 = 9.65685+
Trivial.
17. 
s = 10.44973+
Found by Jonathan Viquerat
in May 2026.
18. 
s = (17√2+29)/5 = 10.60832+
Found by Jonathan Viquerat
in May 2026.
19. 
s = 10.96620+
Found by Haowei Lin
in July 2026.
20. 
s = (39√2+67)/11 = 11.10493+
Found by Jonathan Viquerat
in May 2026.
21. 
s = 11.47891+
Found by Grigory Merzon
in August 2026.
22. 
s = 11.63403+
Found by Grigory Merzon
in August 2026.
23. 
s = 11.86396+
Found by Joshua Wolk
in September 2026.
24.-25. 
s = 5 + 5√2 = 12.07106+
Trivial.
26. 
s = 12.75167+
Found by Joshua Wolk
in September 2026.
27. 
s = 12.91949+
Found by Joshua Wolk
in September 2026.
28. 
s = 13.11977+
Found by Joshua Wolk
in September 2026.
29. 
s = 13.30840+
Found by Joshua Wolk
in September 2026.
30. 
s = 13.38847+
Found by Joshua Wolk
in September 2026.
31. 
s = 13.73323+
Found by Joshua Wolk
in September 2026.
32. 
s = 13.94285+
Found by Joshua Wolk
in September 2026.
33. 
s = 14.05624+
Found by Joshua Wolk
in September 2026.
34. 
s = 14.27818+
Found by Joshua Wolk
in September 2026.
35.-36. 
s = 6 + 6√2 = 14.48528+
Trivial.
37. 
s = 14.97438+
Found by Joshua Wolk
in September 2026.
38. 
s = 15.10712+
Found by Joshua Wolk
in September 2026.
39. 
s = 15.20118+
Found by Joshua Wolk
in September 2026.
40. 
s = 15.51710+
Found by Joshua Wolk
in September 2026.
41. 
s = 15.66801+
Found by Joshua Wolk
in September 2026.
42. 
s = 15.68731+
Found by Joshua Wolk
in September 2026.
43. 
s = 16.03641+
Found by Joshua Wolk
in September 2026.
44. 
s = 16.22423+
Found by Joshua Wolk
in September 2026.
45. 
s = 16.38335+
Found by Joshua Wolk
in September 2026.
46. 
s = 16.47425+
Found by Joshua Wolk
in September 2026.
47. 
s = 16.69239+
Found by Joshua Wolk
in September 2026.
48.-49. 
s = 7 + 7√2 = 16.89950+
Trivial.
50. 
s = 17.29153+
Found by Joshua Wolk
in September 2026.