Capital Adequacy Ratio Calculator — Basel III CAR

Calculate CET1, Tier 1, and Total Capital ratios against Basel III minimums and buffer thresholds. Built for banking students and finance professionals.

July 13, 2026

CET1 Capital ($)

Additional Tier 1 Capital ($)

Tier 2 Capital ($)

Risk-Weighted Assets — RWA ($)

CET1 RatioWell-capitalized

9.00%

Minimum 4.5% · Well-capitalized (with buffer) 7.0%

Tier 1 RatioWell-capitalized

10.00%

Minimum 6.0% · Well-capitalized (with buffer) 8.5%

Total Capital Ratio (CAR)Well-capitalized

11.50%

Minimum 8.0% · Well-capitalized (with buffer) 10.5%

Tier 1 Capital (CET1 + Additional Tier 1) = $10,000,000. Total Regulatory Capital (Tier 1 + Tier 2) = $11,500,000.

CET1 Ratio = CET1 Capital ÷ RWA. Tier 1 Ratio = (CET1 + Additional Tier 1) ÷ RWA. Total Capital Ratio = (Tier 1 + Tier 2) ÷ RWA. Basel III sets minimums of 4.5% / 6.0% / 8.0%, plus a 2.5% capital conservation buffer on top (met with CET1) for commonly cited "well-capitalized" thresholds of 7.0% / 8.5% / 10.5%. This is an educational, illustrative calculator — it does not reflect national-discretion add-ons (countercyclical buffer, G-SIB surcharge, Pillar 2 add-ons) that apply to real banks. It is not a regulatory compliance tool.

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Reference Values

Last verified: Jul 11, 2026

Category	Range	What It Means	Status
CET1 Ratio formula	CET1 Capital ÷ RWA	Common Equity Tier 1 — the highest-quality capital (common stock, retained earnings, disclosed reserves) divided by Risk-Weighted Assets.	Good
Tier 1 Ratio formula	(CET1 + Additional Tier 1) ÷ RWA	Total "going-concern" capital — capital that absorbs losses while the bank keeps operating — divided by RWA.	Good
Total Capital Ratio formula	(Tier 1 + Tier 2) ÷ RWA	All regulatory capital, including "gone-concern" Tier 2 capital, divided by RWA. Also called the Capital Adequacy Ratio (CAR).	Good
CET1 minimum	4.5% of RWA	Basel III regulatory floor. Falling below this triggers supervisory intervention, not just a conservation-buffer restriction.	Okay
Tier 1 minimum	6.0% of RWA	Basel III regulatory floor for total going-concern capital.	Okay
Total Capital minimum	8.0% of RWA	Basel III regulatory floor for CET1 + Additional Tier 1 + Tier 2 combined.	Okay
Capital Conservation Buffer (CCB)	+2.5% of RWA, met with CET1	An extra CET1 cushion on top of the minimums, introduced after the 2008 crisis. Breaching it doesn't close the bank, but it automatically restricts dividends, share buybacks, and discretionary bonus payouts.	Good
CET1 + buffer (well-capitalized) ★	7.0% of RWA	4.5% minimum + 2.5% conservation buffer — the commonly cited "comfortable" CET1 threshold.	★ Best
Tier 1 + buffer (well-capitalized) ★	8.5% of RWA	6.0% minimum + 2.5% conservation buffer.	★ Best
Total Capital + buffer (well-capitalized) ★	10.5% of RWA	8.0% minimum + 2.5% conservation buffer — the commonly cited "well-capitalized" Total Capital threshold.	★ Best
Tier 1 composition ("going-concern")	Common equity, retained earnings, disclosed reserves, qualifying instruments	Capital that absorbs losses while the bank is still a going concern, letting it keep operating and lending.	Good
Tier 2 composition ("gone-concern")	Subordinated debt, certain hybrid instruments, general loan-loss reserves	Lower-quality capital that only absorbs losses in liquidation (a "gone concern") — it cushions depositors and senior creditors after Tier 1 is wiped out.	Good

Source: Bank for International Settlements, "Basel III: A global regulatory framework for more resilient banks and banking systems" and BIS "Definition of Capital in Basel III — Executive Summary" (bis.org); Wikipedia "Basel III" for an accessible summary of minimum ratios and the capital conservation buffer.

Worked Examples

Well-Capitalized Regional Bank

CET1 Capital: $9,000,000
Additional Tier 1: $1,000,000
Tier 2 Capital: $1,500,000
RWA: $100,000,000

CET1 9.00% / Tier 1 10.00% / Total Capital 11.50%

CET1 = 9,000,000 ÷ 100,000,000 = 9.00% (passes both the 4.5% minimum and the 7.0% buffer threshold). Tier 1 = 10,000,000 ÷ 100,000,000 = 10.00% (passes the 8.5% buffer threshold). Total Capital = 11,500,000 ÷ 100,000,000 = 11.50% (passes the 10.5% buffer threshold). All three ratios clear both the bare minimum and the conservation buffer.

Bank Exactly at Basel III Minimums

CET1 Capital: $4,500,000
Additional Tier 1: $1,500,000
Tier 2 Capital: $2,000,000
RWA: $100,000,000

CET1 4.50% / Tier 1 6.00% / Total Capital 8.00%

CET1 = 4,500,000 ÷ 100,000,000 = 4.50% (exactly the floor). Tier 1 = 6,000,000 ÷ 100,000,000 = 6.00% (exactly the floor). Total Capital = 8,000,000 ÷ 100,000,000 = 8.00% (exactly the floor). This bank clears every regulatory minimum but sits below all three buffer-inclusive thresholds (7.0% / 8.5% / 10.5%), meaning the capital conservation buffer is breached — automatic restrictions on dividends, buybacks, and discretionary bonuses would apply.

Undercapitalized Bank (Fails Minimums)

CET1 Capital: $2,500,000
Additional Tier 1: $500,000
Tier 2 Capital: $800,000
RWA: $100,000,000

CET1 2.50% / Tier 1 3.00% / Total Capital 3.80%

CET1 = 2,500,000 ÷ 100,000,000 = 2.50% (fails the 4.5% minimum). Tier 1 = 3,000,000 ÷ 100,000,000 = 3.00% (fails the 6.0% minimum). Total Capital = 3,800,000 ÷ 100,000,000 = 3.80% (fails the 8.0% minimum). All three ratios miss the regulatory floor, not just the buffer — this level would trigger prompt supervisory action in a real jurisdiction.

Strong Core Capital, Thin Tier 2 (Total Ratio Shortfall)

CET1 Capital: $7,200,000
Additional Tier 1: $500,000
Tier 2 Capital: $200,000
RWA: $100,000,000

CET1 7.20% / Tier 1 7.70% / Total Capital 7.90%

CET1 = 7,200,000 ÷ 100,000,000 = 7.20% (passes the minimum and the 7.0% buffer). Tier 1 = 7,700,000 ÷ 100,000,000 = 7.70% (passes the 6.0% minimum but misses the 8.5% buffer). Total Capital = 7,900,000 ÷ 100,000,000 = 7.90% (misses the 8.0% minimum). A bank can have excellent core CET1 capital and still fail the overall Total Capital minimum if its Tier 2 layer is too thin — the three ratios have to be checked independently.

Community Bank Passing Minimums, Missing the Buffer

CET1 Capital: $5,500,000
Additional Tier 1: $800,000
Tier 2 Capital: $1,750,000
RWA: $100,000,000

CET1 5.50% / Tier 1 6.30% / Total Capital 8.05%

CET1 = 5,500,000 ÷ 100,000,000 = 5.50% (passes the 4.5% minimum, misses the 7.0% buffer). Tier 1 = 6,300,000 ÷ 100,000,000 = 6.30% (passes the 6.0% minimum, misses the 8.5% buffer). Total Capital = 8,050,000 ÷ 100,000,000 = 8.05% (barely passes the 8.0% minimum, well short of the 10.5% buffer threshold). Every ratio clears its regulatory floor but none reach the buffer-inclusive "well-capitalized" level.

How to Use This Calculator

1

Enter CET1 Capital

Common Equity Tier 1 — common stock, retained earnings, and disclosed reserves. The highest-quality capital layer.
2

Enter Additional Tier 1 Capital

Qualifying instruments beyond CET1 that still count as going-concern capital (combined with CET1, this makes up total Tier 1).
3

Enter Tier 2 Capital

Subordinated debt, qualifying hybrid instruments, and general loan-loss reserves — the gone-concern layer.
4

Enter Risk-Weighted Assets (RWA)

The bank's total assets after risk-weighting. Read the CET1, Tier 1, and Total Capital ratios instantly, each flagged against the Basel III minimum and the buffer-inclusive well-capitalized threshold.

What Each Value Means

CET1 Ratio (% of RWA): Common Equity Tier 1 capital divided by Risk-Weighted Assets — the strictest and most closely watched of the three Basel III ratios.
Tier 1 Ratio (% of RWA): Total going-concern capital (CET1 + Additional Tier 1) divided by Risk-Weighted Assets.
Total Capital Ratio (CAR) (% of RWA): All regulatory capital (Tier 1 + Tier 2) divided by Risk-Weighted Assets — the headline Capital Adequacy Ratio.
Capital Conservation Buffer (% of RWA): An additional 2.5% of CET1 capital (as a share of RWA) required on top of every Basel III minimum. Breaching it restricts dividends, buybacks, and bonuses without closing the bank.
Risk-Weighted Assets (RWA) (USD): A bank's total assets scaled by risk weight — safer assets count for less, riskier assets count for more — used as the denominator for every Basel III capital ratio.

Frequently Asked Questions

What's the difference between Tier 1 and Tier 2 capital?

Tier 1 is "going-concern" capital — common equity, retained earnings, disclosed reserves, and certain qualifying instruments that absorb losses while the bank keeps operating normally. Tier 2 is "gone-concern" capital — subordinated debt, certain hybrid instruments, and general loan-loss reserves that only step in to absorb losses if the bank is being wound down, protecting depositors and senior creditors after Tier 1 has already been wiped out. Regulators weight Tier 1 more heavily because it's higher quality and available sooner in a stress scenario.

Why does the capital conservation buffer exist?

The capital conservation buffer was added in Basel III specifically because of what happened in the 2008 financial crisis: many banks technically met their minimum capital requirements right up until they failed, because minimums alone gave supervisors no early warning room and gave banks no incentive to build a cushion during good times. The buffer adds an extra 2.5% of CET1 capital on top of every minimum. A bank can dip into the buffer without being shut down, but doing so automatically triggers restrictions on dividends, share buybacks, and discretionary bonus payouts — a graduated, automatic brake that kicks in well before a bank is actually insolvent.

What counts as Risk-Weighted Assets (RWA), and why not just use total assets?

Risk-Weighted Assets scale each asset on a bank's balance sheet by a risk weight before adding them up — a low-risk asset like a government bond might carry close to a 0% weight, while an unsecured business loan might carry 100% or more. Using RWA instead of raw total assets means a bank holding mostly safe assets needs less capital than a bank holding the same dollar amount in riskier loans, which better reflects true loss exposure. This calculator asks you to enter RWA directly since the risk-weighting calculation itself depends on a detailed, asset-by-asset regulatory framework (the Basel standardized or internal-ratings-based approaches) that's outside the scope of a single tool.

What happens if a bank falls below the Basel III minimums, not just the buffer?

Falling below a hard minimum (4.5% CET1, 6.0% Tier 1, or 8.0% Total Capital) is more serious than a buffer breach — it typically triggers prompt supervisory intervention under a jurisdiction's prompt-corrective-action framework, which can include mandated capital raises, restrictions on growth, or in severe cases regulatory takeover. A buffer breach (ratios between the minimum and the minimum-plus-2.5%) is comparatively routine and self-correcting through automatic payout restrictions; missing the underlying minimum itself is a solvency-adjacent regulatory event.

Is this a real bank compliance tool?

No. This calculator applies the published Basel III formulas and headline minimums for education and illustration — it's built for finance students, analysts, and banking professionals who want to sanity-check a CAR calculation quickly. Real-world capital requirements layer on additional national-discretion add-ons (a countercyclical buffer that varies by jurisdiction and can range higher in credit booms, a Global Systemically Important Bank surcharge for the largest institutions, and supervisory Pillar 2 add-ons specific to each bank), none of which this tool applies. Never use this calculator as a substitute for an actual regulatory capital filing or a bank's official capital adequacy assessment process.