Eli5 Do tax rates kick in at each cutoff? Or if you earn a set amount your full income is taxed at the same rate

Question

Just wondering when looking at jobs putting me into higher tax brackets, if tax was say 20% for earning £30k, and £31k a year was taxed at 25%, would my first 30k of income be taxed at the 20% or my full salary taxed at 25%? And if so then how do you ever make jumping up to the next tax band viable?

In: Economics

Answer 1

* In the US they kick in at each level.
* If the the rate for $50,000 a year is A
* And the rate for $100,000 a year is B
* And the you made $120,000 last year:
* You pay the A rate on the first $50,000
* You pay the B rate on the rest.