To calculate the reserve ratio, divide a bank’s total reserves by its net transaction account deposits and multiply by 100. Total reserves are the sum of vault cash and the balance the bank holds at a Federal Reserve Bank. Net transaction account deposits are the bank’s checking and other demand deposit accounts after allowable deductions. The result, expressed as a percentage, shows how much of the bank’s deposit base is sitting in immediately available cash.
The Formula
Reserve Ratio = (Total Reserves ÷ Net Transaction Account Deposits) × 100
Two inputs drive the calculation, and each has a specific definition under Regulation D.
Total reserves have two components. The first is vault cash: U.S. currency and coin the institution holds as an asset on its premises. The second is the balance the bank maintains at a Federal Reserve Bank. Add them together to get the numerator.1eCFR. 12 CFR Part 204 – Reserve Requirements of Depository Institutions (Regulation D)
Net transaction account deposits are the denominator. Start with total transaction accounts — primarily checking and other demand deposits owed to the public — then subtract allowable deductions like cash items in the process of collection and demand balances owed by other depository institutions. Deposits owed to other depository institutions and to the U.S. government are not included in the base to begin with.1eCFR. 12 CFR Part 204 – Reserve Requirements of Depository Institutions (Regulation D)
A Worked Example
Suppose a bank holds $80,000 in vault cash and $120,000 on deposit at the Federal Reserve. Total reserves come to $200,000. If net transaction account deposits total $2,000,000, the calculation runs:
$200,000 ÷ $2,000,000 = 0.10
0.10 × 100 = 10 percent
The bank is holding 10 percent of its deposit base in liquid reserves.
Reading the Result
A higher ratio means more liquidity but less money out earning interest through loans. A lower ratio means more lending capacity and thinner cash on hand for withdrawals. The number by itself is not a pass-or-fail grade; it is a snapshot of how the bank has balanced liquidity against lending on a given day.
Context matters when interpreting it. Since the Federal Reserve reduced the required reserve ratio to zero percent on March 26, 2020, any positive ratio you calculate today reflects reserves the bank is choosing to hold, not reserves it is required to hold.2Federal Reserve Board. Reserve Requirements Banks collectively hold approximately $2.9 trillion in balances at the Federal Reserve as of early 2026, largely because those balances earn the Interest on Reserve Balances (IORB) rate — 3.65 percent as of February 2026, effective December 11, 2025.3Federal Reserve Economic Data. Interest Rate on Reserve Balances (IORB Rate) So a bank showing a ratio well above zero is often earning risk-free interest on those balances, not sitting on idle cash.
Where the Numbers Come From
Banks compile the deposit and reserve figures on Form FR 2900, the Report of Deposits and Vault Cash.4Federal Reserve. Instructions for the Preparation of Report of Deposits and Vault Cash Reporting Form FR 2900 If you are calculating a ratio for a specific institution, the FR 2900 inputs are the authoritative source. Building the two numbers involves four steps.
- Sum transaction accounts. Add demand deposits due to the public — chiefly checking accounts — along with other liquid deposits. Exclude deposits owed to other depository institutions and to the U.S. government.
- Subtract deductions. Remove cash items in the process of collection and demand balances owed by other depository institutions. What remains is net transaction accounts, the denominator of the ratio.1eCFR. 12 CFR Part 204 – Reserve Requirements of Depository Institutions (Regulation D)
- Separate time deposits. Small time deposits (under $100,000) and large time deposits are reported separately and do not enter the transaction account total. The FR 2900 instructions explain how to classify accounts that resemble time deposits but function as transaction accounts.5Federal Reserve System. FR 2900 Report of Deposits and Vault Cash File Upload User Guide
- Record vault cash. Total U.S. currency and coin held on the institution’s premises. Add that to the Federal Reserve balance to get total reserves, the numerator.
Liabilities That Do Not Count
Some things a bank owes are not “deposits” for Regulation D purposes and do not belong in the denominator. Excluded categories include trust funds properly segregated from the bank’s general assets, accounts payable, conditional or contingent obligations, and obligations whose proceeds are not used for lending or investment — such as debt issued to buy equipment or business premises.1eCFR. 12 CFR Part 204 – Reserve Requirements of Depository Institutions (Regulation D) Deposits payable only at offices outside the United States are also excluded. Miscategorizing any of these can throw the calculation off in either direction.
The Requirement Itself Is Zero, but the Framework Is Live
The Board reduced the required ratio to zero across all three tiers of net transaction accounts in March 2020, which freed roughly $200 billion in reserves banks could redirect to lending.2Federal Reserve Board. Reserve Requirements The tier thresholds still get indexed each year. For 2026, the reserve requirement exemption amount is $39.2 million in net transaction accounts, and the low reserve tranche is $674.1 million.6Federal Register. Regulation D: Reserve Requirements of Depository Institutions Under 12 USC 461, the Board can set the ratio as high as 3 percent on the lower tranche and up to 14 percent on the upper tier.7Office of the Law Revision Counsel. 12 USC 461 – Reserve Requirements
Practically, this means the ratio you calculate is currently a liquidity metric rather than a compliance check. If the Board raises the ratio above zero, the same formula and the same FR 2900 inputs are what will determine whether an institution meets its requirement.
Reserve Ratio Is Not Capital Adequacy Ratio
The reserve ratio is sometimes confused with the capital adequacy ratio, but they measure different things. The reserve ratio compares liquid cash and Federal Reserve balances to deposits, showing whether a bank can handle day-to-day withdrawals. The capital adequacy ratio compares a bank’s capital — equity and certain reserves — to its risk-weighted assets, showing whether the bank can absorb unexpected losses on loans and investments.8Federal Deposit Insurance Corporation. An Evaluation of the Denominator of the Reserve Ratio FDIC Staff Study Capital adequacy uses sophisticated risk modeling; the reserve ratio is the simpler arithmetic laid out above. If your goal is to gauge liquidity, the reserve ratio is the right number. If your goal is to gauge loss-absorbing strength, it is not.