Quarterly income is the total money you earned, or the profit your business generated, during a three-month period. You calculate it by adding up every dollar of revenue received during those three months and subtracting the expenses incurred over the same window; the result is your net quarterly income. The gross figure is the revenue alone, before anything comes out. Both numbers have their uses, and which one people ask for depends on what they’re trying to see.
The reason to track it at all comes down to two things. Individuals with income that isn’t subject to employer withholding generally have to make estimated tax payments to the IRS four times a year, based on what they earned each quarter.1Internal Revenue Service. Form 1040-ES, Estimated Tax for Individuals Businesses use the quarterly number to track performance, file reports with regulators, and correct course before the year closes.
How the Quarterly Calendar Works
A standard calendar year splits into four three-month blocks:
- Q1: January through March
- Q2: April through June
- Q3: July through September
- Q4: October through December
Some organizations run on a fiscal year that starts on a different date. The federal government’s fiscal year begins October 1, so its Q1 is October through December. The three-month structure stays intact whichever start date you use, which is what makes quarter-over-quarter and year-over-year comparisons meaningful.
Gross vs. Net Quarterly Income
Gross quarterly income is total revenue collected during the three-month window before any deductions. For a freelancer that’s every client payment; for a retailer it’s total sales. The number can look strong while telling you very little about whether you actually made money.
Net quarterly income is what remains after you subtract expenses: operating costs, materials, payroll, interest, and taxes. This is the profitability figure. A business can post healthy gross revenue and still lose money if expenses run higher. When a lender, an investor, or the IRS wants to understand your financial position, net income is almost always the number that matters.
How to Calculate Quarterly Income
The core math is straightforward. Add every dollar of revenue earned across the three months of the quarter to get gross quarterly income. Add every expense incurred during those same three months and subtract that total from revenue. What’s left is your net quarterly income.
Cost of Goods Sold for Product Sellers
If you sell physical products, calculate cost of goods sold before you get to profit. The formula is beginning inventory plus purchases during the quarter, minus ending inventory. That tells you what you actually spent on the goods that left your shelves, as opposed to what’s still sitting in stock. Subtract cost of goods sold from revenue to reach gross profit, then subtract the rest of your operating expenses to reach net income.
A Worked Example
Say you run a small online store. In Q2, sales total $45,000. You started the quarter with $8,000 in inventory, purchased $12,000 more, and ended with $6,000 unsold. Cost of goods sold is $14,000 ($8,000 + $12,000 − $6,000), leaving $31,000 in gross profit. If operating expenses for the quarter, including rent, software subscriptions, shipping, and contractor payments, total $18,000, your net quarterly income is $13,000.
Cash vs. Accrual: When Revenue Counts
The accounting method you use decides which quarter a transaction lands in, and the choice can move thousands of dollars between periods.
Under cash accounting, income counts when the money hits your account and expenses count when you pay them. Invoice a client $5,000 in March and receive payment in April, and that revenue belongs to Q2, not Q1. Most freelancers and small businesses use the cash method because it tracks what’s actually in the bank.
Under accrual accounting, income counts when you earn it, meaning when you deliver the goods or complete the service, regardless of when you get paid. That same March invoice would count as Q1 revenue even if the check clears in April. Expenses follow the same rule: recorded when incurred, not when paid.
The IRS lets most small businesses choose. Corporations and partnerships whose average annual gross receipts over the prior three years exceed $32 million are generally required to use accrual accounting.2Internal Revenue Service. Revenue Procedure 2025-32 – 2026 Adjusted Items The base statutory threshold is $25 million, adjusted annually for inflation.3Office of the Law Revision Counsel. 26 U.S. Code 448 – Limitation on Use of Cash Method of Accounting
Records You Need to Get the Number Right
An accurate quarterly figure comes out of organized records. At minimum, pull together:
- Revenue records: sales receipts, client invoices, and payment processor reports covering every dollar that came in.
- Bank and brokerage statements, which capture interest, dividends, and anything that doesn’t show up on an invoice.
- Expense records: receipts for supplies, rent, utilities, contractor invoices, and subscriptions.
- Payroll reports, if you have employees, including wages, benefits, and employer-side payroll taxes for the quarter.
- Beginning and ending inventory counts, if you sell physical products, for the cost of goods sold calculation.
Most accounting software will consolidate these and produce a quarterly profit and loss statement on demand. If you track income by hand, monthly bank statements are the floor: they catch deposits and payments you’d otherwise forget. Basing your quarterly figures on verified transactions rather than estimates is what keeps tax payments accurate later on.
Where the Number Gets Used
Quarterly income feeds more than your tax return. A short tour of the places it turns up:
Estimated Taxes
Self-employed people, freelancers, landlords, and anyone else earning income without employer withholding generally have to make quarterly estimated tax payments using Form 1040-ES if they expect to owe at least $1,000 in federal income tax after subtracting withholding and refundable credits.4Internal Revenue Service. About Form 1040-ES, Estimated Tax for Individuals The payment periods don’t split into even three-month blocks, so mark the actual IRS due dates rather than assuming they fall at the end of each calendar quarter.1Internal Revenue Service. Form 1040-ES, Estimated Tax for Individuals
SEC Reporting
Publicly traded companies file Form 10-Q with the Securities and Exchange Commission for each of the first three quarters of their fiscal year, disclosing unaudited financial results.5eCFR. 17 CFR 240.13a-13 – Quarterly Reports on Form 10-Q The fourth quarter is folded into the annual 10-K. These are the quarterly snapshots investors and analysts read to judge whether a company is on plan.
Loan Applications
Lenders evaluating self-employed borrowers often ask for quarterly profit and loss statements or bank statements covering the most recent two to four quarters. A W-2 employee’s income verifies quickly; a business owner’s does not. Quarterly documents let the lender see whether income is stable, climbing, or leaning on one strong quarter that may not repeat.
Marketplace Subsidies
Premium tax credits through the ACA Marketplace are based on projected annual income. When your quarterly earnings change significantly, reporting the change promptly adjusts your monthly premium to match. Failing to report higher income can mean paying back part or all of the credit at tax time.6CMS. Report Life Changes When You Have Marketplace Coverage Reporting a drop can raise your subsidy and lower your monthly payments right away.
Social Security Earnings Test
If you’re collecting Social Security retirement benefits before full retirement age and still working, your benefits are reduced once earnings pass certain limits. In 2026, the annual limit is $24,480 for beneficiaries who won’t reach full retirement age during the year, with $1 in benefits withheld for every $2 earned above that threshold. In the year you reach full retirement age, the limit rises to $65,160, with $1 withheld for every $3 above it.7Social Security Administration. Receiving Benefits While Working Watching quarterly income shows you early whether you’re on pace to cross those lines.
Unemployment Benefits
State unemployment agencies set weekly benefit amounts using a base period of quarterly wages from your recent work history. Most states use the first four of the last five completed calendar quarters before the claim. Some calculate benefits from your highest-earning quarter; others average across multiple quarters.8U.S. Department of Labor. Monetary Entitlement One strong quarter and three weak ones can produce very different benefit amounts depending on your state’s formula.