Basel III minimum capital requirements
The Basel Committee's minimum capital ratios and buffers, in one table.
| Requirement | Level | Basis |
|---|---|---|
| Common Equity Tier 1 | 4.5% | RWA |
| Tier 1 capital | 6.0% | RWA |
| Total capital (Tier 1 + Tier 2) | 8.0% | RWA |
| Capital conservation buffer | 2.5% (CET1) | RWA |
| Countercyclical capital buffer | 0 to 2.5% (CET1) | RWA |
| G-SIB higher loss absorbency | By bucket | RWA |
| Leverage ratio | 3% (Tier 1) | Exposure measure |
| G-SIB leverage buffer | 50% of G-SIB surcharge | Exposure measure |
How the layers stack
A bank must meet the 4.5% CET1, 6% Tier 1 and 8% total capital minimums at all times. On top of that, the capital conservation buffer is 2.5% of RWA and must be met with CET1; the countercyclical buffer varies between 0 and 2.5% of RWA and must also be met with CET1. Because CET1 is used first to meet the Tier 1 and total capital minimums, any shortfall in Additional Tier 1 or Tier 2 reduces the CET1 available for buffers.
Local rules differ
Basel III is a global standard that jurisdictions implement through their own laws (for example EU, UK and US rules). They may apply stricter requirements or different transition dates. Always check your supervisor's rules.
Frequently asked questions
What are the Basel III minimum capital ratios?
4.5% CET1, 6% Tier 1 and 8% total capital, as a share of risk-weighted assets, plus a 3% leverage ratio on Tier 1.
What is the capital conservation buffer?
An extra 2.5% of RWA in CET1 on top of the minimums. Falling into the buffer restricts distributions.
Are these requirements the same everywhere?
No. Jurisdictions implement Basel III in their own rules and may be stricter or earlier.
Sources: Basel Committee on Banking Supervision, Basel Framework (RBC20 calculation of minimum risk-based capital requirements; LEV20 leverage ratio) and Basel III international regulatory framework for banks, bis.org; BIS FSI summary of the capital conservation and countercyclical buffers. Checked 10 October 2026.