Bring last year's returns, every income form you receive (W-2s, 1099s, K-1s), records of deductible expenses and estimated payments, and, if you own a business, a year-end profit and loss statement, balance sheet and payroll reports. The most useful habit is to send what you have as it arrives rather than waiting for the last form.
A complete set of documents is the single biggest factor in how quickly and accurately your return gets done. Not every item below will apply to you. Use the lists to check what you have, and flag anything you are unsure about rather than leaving it out.
Before you start: what changed this year?
The documents matter less than the changes behind them. Before you gather anything, write down what was different about 2026. Did you marry or divorce, have a child, buy or sell a home, move to or from Colorado, start a business, sell investments, or retire? Each of those changes the return, and each tends to produce paperwork you might not think of as a tax document, like a closing statement or a divorce decree. A short note with those changes saves your CPA time and saves you follow-up questions.
Documents everyone needs
- Social Security numbers and dates of birth for you, your spouse and any dependents
- Last year’s federal and Colorado returns, if we did not prepare them
- Bank account and routing numbers for a refund or payment
- A government-issued photo ID
- Any IRS or Colorado Department of Revenue letters received during the year
Income documents
- W-2s from every employer. For 2026 wages, employers must furnish them by February 1, 2027, per the IRS instructions for Forms W-2 and W-3.
- 1099-NEC for contract work. Starting with 2026 payments, a business generally issues one only when it pays you $2,000 or more, up from $600, according to IRS Publication 15. Income below that is still taxable, so bring your own totals.
- 1099-K from payment apps and card processors. These are now issued only when payments exceed $20,000 and transactions exceed 200, after the threshold reverted.
- 1099-INT and 1099-DIV for interest and dividends.
- 1099-B for sales of stocks, funds or crypto, including cost basis.
- 1099-R for retirement plan and IRA distributions, and SSA-1099 for Social Security benefits.
- Schedule K-1s from partnerships, S corporations, estates and trusts. If a business you own elected to pay Colorado tax at the entity level, bring the Colorado K-1 (DR 0106K) too.
- Rental property records: rents received, expenses, and closing statements for any property bought or sold.
- Anything else: alimony under older divorce agreements, gambling winnings, jury pay, or income from outside the U.S.
Deduction and credit documents
- Form 1098 for mortgage interest, and property tax statements
- Receipts or acknowledgment letters for charitable gifts, including non-cash donations
- Medical expenses, if they were large this year
- Form 1098-E for student loan interest and Form 1098-T for tuition
- Child and dependent care costs, with each provider’s name, address and tax ID
- Form 1095-A if you bought health coverage through Connect for Health Colorado or another marketplace
- Records of energy-related home improvements, with invoices
- Dates and amounts of every federal and Colorado estimated tax payment you made for 2026, including any payment made in January 2027
That last item causes more back-and-forth than any other. Estimated payments are easy to forget, and a payment the return does not know about shows up as a balance due and a notice later.
For business owners
If you are a sole proprietor, a partner or an S corporation shareholder, bring the documents above plus:
- A year-end profit and loss statement and balance sheet, with bank and credit card accounts reconciled through December 31
- Payroll reports: quarterly Forms 941, annual W-2 and W-3 totals, and Colorado wage withholding filings
- A list of 1099s you issued to contractors, with the W-9s behind them
- Fixed asset purchases: invoices showing the date each item was bought and placed in service
- Loan statements showing year-end balances and interest paid
- Vehicle mileage logs with dates, destinations and business purpose
- Home office details: the square footage used regularly and exclusively for business and the total square footage of the home
- Health insurance premiums and retirement plan contributions paid for owners
- Colorado and Denver filings: state sales tax returns, Denver sales or use tax returns and Occupational Privilege Tax returns, if they apply to you
If you use QuickBooks Online, Xero or similar software, giving your CPA accountant access is usually faster and cleaner than exporting reports.
Why dates matter as much as dollars
Two 2026 rules show why dates on your records matter.
First, the IRS business standard mileage rate changed mid-year: 72.5 cents a mile from January 1 through June 30, 2026, and 76 cents from July 1 through December 31. Suppose, for illustration, you drove 8,000 business miles, half in each part of the year. With a dated log, the deduction is $2,900 plus $3,040, or $5,940. Without dates, the safe assumption is the lower rate on every mile, or $5,800.
Second, equipment purchases depend on when an asset was acquired and placed in service. IRS Publication 946 explains that 100% bonus depreciation was reinstated for qualifying property acquired and placed in service after January 19, 2025. An invoice with a date answers the question. A credit card line that just says the vendor’s name does not.
A simple way to stay organized
Keep one folder, physical or digital, labeled for the tax year. Drop each document in as it arrives from January through March. When the stack stops growing, compare it with last year’s return: every 1099, K-1 and account that appeared last year should appear again, or you should know why it does not. That one comparison catches most missing items before your CPA has to ask.
If you would rather have someone keep this organized all year, our accounting and bookkeeping team can, and our tax planning and preparation work starts from records that are already clean.
Common questions
When should I send my documents to my CPA?
Send forms as they arrive rather than in one batch. Employers must furnish 2026 W-2s by February 1, 2027, but partnership and S corporation K-1s often arrive in March or later, so a return that waits on a K-1 may need an extension.
What if I am missing a form?
Tell your CPA what is missing rather than leaving it out. Most income still has to be reported even if a form never arrives, and many missing documents can be pulled from an online account at your bank, brokerage or the IRS.
Do I need a 1099 for income from a payment app?
Payment apps and card processors issue Form 1099-K only when payments exceed $20,000 and the transactions exceed 200. Income below that threshold is still taxable, so bring your own records of what you received.
Why does my CPA want my mileage log by date?
The IRS business mileage rate changed partway through 2026, from 72.5 cents a mile for January through June to 76 cents a mile from July 1. Miles driven in the second half of the year are worth more, but only if you can show when you drove them.