How to Calculate Total Reserves: Formula, Ratios, and Steps

To calculate how to calculate total reserves for a depository institution, add required reserves to excess reserves: required reserves equal the reserve requirement ratio applied to each tier of your net transaction accounts, and excess reserves equal your vault cash plus your balance at the Federal Reserve Bank, minus required reserves.¹ One fact reshapes the arithmetic right now: since March 26, 2020, the Federal Reserve has set every reserve requirement ratio to zero percent, and they remain zero in 2026.² Required reserves are therefore zero for every institution, and total reserves currently equal whatever balances a bank voluntarily holds at its Reserve Bank plus its vault cash. The tiered framework still exists in regulation and is still indexed each year, so the full calculation matters for compliance work, exam preparation, and any future decision by the Fed to raise ratios again.

The Formula

Total Reserves = Required Reserves + Excess Reserves

Required reserves are what a bank must hold based on the reserve requirement ratio applied to its net transaction accounts. Excess reserves are everything held above that minimum. Add the two and you have total reserves. With ratios at zero, required reserves drop out, and total reserves equal the bank’s reserve balances at its Federal Reserve Bank combined with its vault cash.¹

Pull the Three Numbers You Need

Before any math, gather three figures from your institution’s books, using close-of-business balances for each day of the reporting period.

Net transaction accounts. Start with total transaction accounts, which include demand deposits, automatic transfer service (ATS) accounts, and share draft accounts. Subtract allowable deductions: cash items in the process of collection, and balances due from other domestic depository institutions that are subject to immediate withdrawal. What remains is your net transaction account balance.³
Vault cash. Physical currency and coin on your premises. Under the lagged reserve requirement system, vault cash from a prior computation period counts toward the corresponding maintenance period.⁴
Reserve balance at the Federal Reserve Bank. The funds in your institution’s master account at its district Reserve Bank.

Weekly FR 2900 filers must base the deposit data on the contractual liability to counterparties, including accrued interest.⁵ Accuracy is worth the effort at this stage. Federal Reserve staff review submitted numbers closely and will ask for revisions if something looks off.

Apply the Tiered Ratios to Net Transaction Accounts

Regulation D, at 12 CFR Part 204, sets up a tiered structure for reserve requirements on net transaction accounts.⁶ Every ratio currently sits at zero, but the Board is required by statute to index the tier thresholds each year and does so through a Federal Register notice. For 2026 the thresholds are:²

Exemption amount: net transaction accounts from $0 to $39.2 million, at a 0 percent reserve requirement.
Low reserve tranche: balances from $39.2 million to $674.1 million, at 0 percent (historically 3 percent).
Above the low reserve tranche: balances over $674.1 million, at 0 percent (historically 10 percent).

The exemption amount rose from $37.8 million in 2025 to $39.2 million in 2026, and the low reserve tranche moved from $645.8 million to $674.1 million.²

Calculate Required Reserves

Apply the ratio for each tier to the portion of net transaction accounts that falls within it, then add the tier amounts together. If the historical ratios were in force, a bank with $800 million in net transaction accounts would owe nothing on the first $39.2 million (exemption), 3 percent on the next $634.9 million (the slice between $39.2 million and $674.1 million), and 10 percent on the remaining $125.9 million above the tranche. Total those three amounts and you have required reserves.

Under the current zero-percent regime, this step produces zero for every institution regardless of size. The Board’s 2026 Federal Register notice states plainly that the annual indexation “will not affect depository institutions’ reserve requirements, which will remain zero.”² If the Fed ever restores non-zero ratios, this tiered multiplication is the step that produces the required reserve figure you plug into the total.

Calculate Excess Reserves

Excess Reserves = (Vault Cash + Reserve Balance at the Fed) − Required Reserves

Add vault cash from the applicable computation period to the master account balance at the Reserve Bank, then subtract required reserves. A positive result is the cushion above the legal minimum. With required reserves at zero, excess reserves equal the full amount of vault cash and Fed balances combined.

Banks track this figure because balances in the master account earn interest. Since July 29, 2021, the Federal Reserve has paid a single Interest on Reserve Balances (IORB) rate on all balances held in master accounts, replacing the earlier split between the IOER rate on excess reserves and the IORR rate on required reserves.⁷ The IORB rate is 3.65 percent as of March 2026.⁸ It is set by the Board of Governors and is one of the main tools for implementing the FOMC’s monetary policy decisions.

Sum and Reconcile

Add required reserves to excess reserves. The result is total reserves. Record it in your accounting system and reconcile against the general ledger. The number should match the combined vault cash and Federal Reserve Bank balances on your daily balance sheets. If it doesn’t, find the discrepancy before you report the data, because Reserve Bank staff scrutinize submissions and will request explanations for unexplained movements.⁵ If errors surface after submission, notify your Reserve Bank contact about the nature of the errors and the periods affected. The Reserve Bank will decide whether revised data need to be filed.

Match the Numbers to the Right Dates

The calculation only works if the deposit figures and reserve holdings come from the correct periods. Institutions that file the FR 2900 weekly maintain their reserve balances over a 14-day maintenance period, which begins on the third Thursday after the corresponding computation period ends.⁹ Quarterly reporters follow a similar schedule, with maintenance intervals starting on either the fourth or fifth Thursday after their reporting period ends.

The lag between measuring deposits and holding reserves is deliberate. Under the lagged reserve requirement system adopted in 1998, the computation period for weekly reporters starts roughly 30 days before its corresponding maintenance period.⁴ Vault cash from that computation period is what counts toward required reserves during the maintenance window. The gap gives institutions time to calculate what they owe and arrange their holdings before the maintenance period opens. The FR 2900 report itself is filed through the Federal Reserve’s electronic platform, Reporting Central.¹⁰

What Happens If You Fall Short

With ratios at zero, no institution can be deficient on required reserves right now, so deficiency charges are effectively moot. When ratios are above zero, Reserve Banks assess a deficiency charge at 1 percentage point above the primary credit rate in effect on the first day of the month when the deficiency occurred, applied to the daily average deficiency across the maintenance period.¹¹ The Board can waive the charge case by case. Separate from Regulation D, the regulatory infrastructure around deposit reporting and other Regulation D provisions remains active, so accurate calculation and timely filing still matter even in a zero-ratio environment.

1
Federal Reserve Board. Aggregate Reserves of Depository Institutions and the Monetary Base
2
Federal Register. Regulation D: Reserve Requirements of Depository Institutions
3
eCFR. 12 CFR 204.2 – Definitions
4
Federal Reserve Board. Reserve Requirements
5
Board of Governors of the Federal Reserve System. Instructions for the Preparation of Report of Deposits and Vault Cash Reporting Form FR 2900
6
eCFR. 12 CFR Part 204 – Reserve Requirements of Depository Institutions (Regulation D)
7
Federal Reserve Board. Interest on Reserve Balances (IORB) Frequently Asked Questions
8
Federal Reserve Board. Interest on Reserve Balances
9
eCFR. 12 CFR 204.5 – Maintenance of Required Reserves
10
Federal Reserve Bank Services. Reporting Central
11
eCFR. 12 CFR 204.6 – Charges for Deficiencies