Definitely by 1910 I think. Thats when Britain got nerfed really badly.

What*

Right around the 2nd industrial revolution, ~1870s.

aka the "guilded age"

1776
*mic drop*

Originally posted by HypersleepyNaputunia:

When were the 2 powers abouy equal in strength and dominance
1910?
1920?
1945?

Once Bretton Woods was signed, that was the downfall of the UK as an empire.

Originally posted by Fake:

1776
*mic drop*

That is just so wrong. You do know they still needed to cosy up to the British by Civil War times, right?

Anyway 1960 is the year OP is looking for

They never did 🇬🇧💪

Windscale.

Originally posted by HypersleepyNaputunia:

When were the 2 powers abouy equal in strength and dominance
1910?
1920?
1945?

1890 for economy

1942 for military

Originally posted by Talby:

Right around the 2nd industrial revolution, ~1870s.

aka the "guilded age"

dont think so usa still recover from civil war and reform southern part, also western cost was not full developed

Originally posted by Fuki:

Anyway 1960 is the year OP is looking for

sorry man, but in 1960 uk already being bullied by usa and soviet in suez canal crisis

Right after WW1 the writing was already on the wall for every European Empire. WW2 just ensured that most colonies would break away within a few decades. You can argue that during the American Civil War, the US temporarily surpassed the UK in military power and potential manufacturing, but after the war, militarily at least the US cut their military to a level they really were not a threat to the Empire.

The US peaked right at the end of the cold war, it had unsustainable spending to bankrupt the Soviet Union, and ultimately ended up bankrupting itself when it decided to outsource it's technology and manufacturing capacity overseas. Europe has followed that trend which limits any nation rising to be competitive to the third world, so Asia will be the major players for a few decades until they fall into the same trap of losing manufacturing.