How do I calculate the non-interest income to revenue ratio?

Divide the bank's non-interest income by its total revenue. Total revenue equals net interest income plus non-interest income. The result, expressed as a percentage, shows how much of the bank's revenue comes from fees and other non-lending sources rather than from interest on loans and securities.

The formula is:

Non-Interest Income to Revenue = Non-Interest Income / (Net Interest Income + Non-Interest Income)

The result is expressed as a percentage.

Step-by-Step Calculation

1. Find non-interest income on the income statement. This line item captures all revenue the bank earns outside of lending, from service fees to trading gains. The detailed breakdown of what falls under this category is covered below. 2. Find net interest income on the income statement. This is total interest income minus total interest expense, representing the bank's earnings from its core lending and investing activities. 3. Add non-interest income and net interest income together. The sum is the bank's total revenue. 4. Divide non-interest income by total revenue.

Worked example: A bank reports net interest income of $300 million and non-interest income of $95 million. Total revenue = $300M + $95M = $395 million. Non-interest income to revenue = $95M / $395M = 24.1%. That means roughly one-quarter of this bank's revenue comes from sources other than lending.

What Counts as Non-Interest Income

The specific line items vary by bank and business model, but common categories include:

Service charges and fees on deposit accounts

Wealth management and trust fees

Mortgage origination and servicing fees

Card and payment processing interchange

Insurance commissions

Investment banking advisory fees

Trading gains and losses

Gains and losses on securities sales

Bank-owned life insurance (BOLI) income

The notes to the financial statements typically provide a detailed breakdown of these categories. Pay attention to which ones are the largest, since that tells you where the bank's fee-generating capabilities are concentrated. A bank earning most of its non-interest income from wealth management has a very different revenue profile than one relying heavily on mortgage banking.

Adjustments for a Cleaner Ratio

Securities gains and losses can distort the ratio in any given quarter because they tend to be lumpy and non-recurring. Some analysts exclude securities gains and losses from both the numerator and the denominator to calculate a "core" non-interest income ratio that better reflects recurring fee income capacity. Gains or losses on sales of branches, subsidiaries, or other assets should also be treated as one-time items.

If you're comparing the ratio across quarters or across banks, stripping out these volatile items gives you a more stable view of how much fee revenue the bank actually generates on an ongoing basis.

What the Ratio Tells You

This ratio is fundamentally about revenue diversification. A bank that earns a large share of its revenue from fees is less dependent on the interest rate cycle. When rates fall and net interest margins compress, banks with strong fee income streams tend to hold up better because a meaningful portion of their revenue is not tied to the spread between lending and borrowing rates.

That said, a higher ratio is not automatically better. Fee businesses come with their own cost structures and risks. Wealth management requires well-compensated relationship managers. Investment banking carries volatile deal flow. Mortgage banking is highly cyclical, surging during refinancing booms and declining when rates rise. The quality and stability of the fee income matters as much as its size.

Typical Ranges by Bank Type

The ratio varies widely depending on a bank's size and business mix:

Community banks often fall in the 10% to 20% range. Their revenue is heavily concentrated in lending, with fee income coming primarily from deposit service charges and occasional mortgage origination.

Regional banks typically range from 20% to 35%. They tend to have more developed fee businesses in areas like wealth management, treasury services, and insurance.

Large diversified banks can exceed 40% to 50%. Institutions with major capital markets, trading, or asset management divisions generate substantial non-interest income that can rival or exceed their net interest income.

These ranges shift with interest rate conditions. During periods of very low rates, net interest income gets compressed, which mechanically pushes the non-interest income ratio higher even if fee income dollars haven't changed. The reverse happens when rates rise sharply.

Connection to the Efficiency Ratio

A bank with high non-interest income may show a higher efficiency ratio because fee businesses like wealth management require significant compensation expense. But it may also have a lower net overhead ratio because fee income offsets a larger share of total operating expenses. The non-interest income ratio helps explain why some banks with seemingly high efficiency ratios still generate strong returns on assets and equity.

This is one reason you should not evaluate the efficiency ratio in isolation. Two banks with 65% efficiency ratios can have very different earnings profiles if one generates 40% of revenue from fees and the other generates 15%.

Common Calculation Mistakes

The most frequent error is using total interest income as the denominator instead of net interest income. Total interest income does not account for the bank's funding costs, so using it inflates the denominator and understates the non-interest income ratio. Always use net interest income (interest income minus interest expense) as the lending revenue component.

Another common mistake is comparing banks at different points in the interest rate cycle without adjusting for how rates affect the denominator. A bank's non-interest income in dollar terms may be perfectly stable, but its ratio can swing noticeably as net interest income expands or contracts with rate movements.

Where to Find the Inputs

Both net interest income and non-interest income appear on the income statement in 10-K and 10-Q filings. Detailed non-interest income breakdowns are typically in the notes to the financial statements. Some banks report this ratio directly in their earnings releases or investor presentations, sometimes labeled as "fee income ratio" or "non-interest revenue share."