# Discover premium tax resources for startups and small businesses

Our custom calculators, expert-written articles, and webinars will help prepare your company for tax season—or any season.

## Popular articles

### [Tax planning for small businesses](/content/learn/startups/tax-planning/index.html)

*Author: The Carta Policy Team*
*Date: October 2023*
Small businesses owners and entrepreneurs can use these tax planning strategies to save on taxes and maximize business growth.

### [Business tax deadlines 2026: Corporations and LLCs](/content/learn/startups/tax-planning/business-tax-deadlines/index.html)

*Founder Education*
*Date: March 2026*
Key tax deadlines are coming up in 2026 for LLC and corporation businesses. Here are the dates and IRS forms you need to know.

### [How taxes work for LLCs](/content/learn/startups/tax-planning/llc-taxation/index.html)

*Founder Education*
*Date: April 2025*
Learn how LLC taxation works, what makes LLCs “pass-through” entities, how different types of equity are taxed, and why LLCs avoid double taxation.

### [Tax advisors](/content/learn/startups/tax-planning/tax-advisor/index.html)

*Equity Education*
*Date: November 2022*
A tax advisor works with you to model different scenarios that can help minimize your tax liability while staying compliant with the U.S. tax code.

## Documents and forms

### [What is a Schedule K-1 tax form?](/content/learn/startups/tax-planning/schedule-k-1-tax-form/index.html)

### [Understanding Form 1120-S: Tax return for an S-Corporation](/content/learn/startups/tax-planning/form-1120s/index.html)

### [What is Form 3921?](/content/learn/startups/equity-management/form-3921/index.html)

Meet Carta’s Equity Tax Advisors
Our team is available for unlimited 1:1 sessions, hosting company-wide webinars, and featured in our on-demand education videos.

### [The qualified small business stock (QSBS) tax benefit](/content/learn/startups/tax-planning/qsbs/index.html)

### [Introducing QSBS Attestation](/content/product-updates/introducing-qsbs-attestation/index.html)

### [QSBS stacking and packing](/content/learn/startups/tax-planning/qsbs/stacking-packing/index.html)

How to pay less taxes on your startup shares
In this episode of Startup Essentials, we break down all the basics that founders, employees, and investors need to know about QSBS — a federal tax exclusion that could provide an enormous tax break when selling shares of a company.

### [QSBS calculator](/content/learn/resources/qsbs-calculator/index.html)  
### [2025 AMT calculator](/content/amt-calculator/index.html)  
### [Tax season resources](/content/resources/tax-filing-season/index.html)

## Taxes and employee equity

### [Form 6251 and AMT](/content/learn/equity/stock-options/taxes/form-6251/index.html)

*Equity*
*Date: January 2026*
IRS Form 6251 is a worksheet that helps you determine if you owe AMT and how much. You can also calculate your estimated AMT using our AMT calculator.

### [Filing an 83(b) election: What every founder needs to know](/content/learn/equity/stock-options/taxes/83b-election/index.html)

### [How stock options are taxed: A complete guide](/content/learn/equity/stock-options/taxes/index.html)

### [How to answer three common employee stock option tax questions](/content/learn/startups/compensation/employee-equity/employee-questions/index.html)

### [The alternative minimum tax (AMT), explained](/content/learn/equity/stock-options/taxes/amt/index.html)

### [Cashless exercise](/content/learn/equity/stock-options/exercising/cashless-exercise/index.html)

### [The $100K ISO limit](/content/learn/equity/stock-options/taxes/100k-iso-limit/index.html)