Some 136 countries have agreed a global minimum 15% corporation tax, meaning multinational corporations will pay the rate in each country they operate in.
The reforms were agreed in principle by the G7 at talks chaired by the chancellor Rishi Sunak in June.
The aim is for these rules to be implemented and effective from 2023.
The deal struck means that firms with at least a 10% profit margin will see 25% of any profit above the 10% profit margin reallocated and then subjected to tax in the countries they operate.
Previously countries had only agreed to reallocating “between 20% and 30%”.
Sunak said: “I am proud that the UK has taken a leading role in the world’s efforts to upgrade the global tax system for the modern age – a key priority of our G7 presidency.
“We now have a clear path to a fairer tax system, where large global players pay their fair share wherever they do business.”