# 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

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

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

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

Equity Education  
November 2022  
Tax advisors  
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?**](https://fund-forecasting@carta.com/learn/startups/tax-planning/schedule-k-1-tax-form/)

[**Understanding Form 1120-S: Tax return for an S-Corporation**](https://fund-forecasting@carta.com/learn/startups/tax-planning/form-1120s/)

[**What is Form 3921?**](https://fund-forecasting@carta.com/learn/startups/equity-management/form-3921/)

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.

## Understanding QSBS

[**The qualified small business stock (QSBS) tax benefit**](https://fund-forecasting@carta.com/learn/startups/tax-planning/qsbs/)

[**Introducing QSBS Attestation**](https://fund-forecasting@carta.com/product-updates/introducing-qsbs-attestation/)

[**QSBS stacking and packing**](https://fund-forecasting@carta.com/learn/startups/tax-planning/qsbs/stacking-packing/)

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.

## Popular tools

[**QSBS calculator** 
View tool](https://fund-forecasting@carta.com/learn/resources/qsbs-calculator/)

[**2025 AMT calculator** 
View tool](https://fund-forecasting@carta.com/amt-calculator/)

[**Tax season resources** 
Learn more](https://fund-forecasting@carta.com/resources/tax-filing-season/)

## Taxes and employee equity

Author: The Carta Team  
Date: March 2024  
featured article  
Form 6251 and AMT  
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.

Equity  
January 2026  
Filing an 83(b) election: What every founder needs to know  
Learn what a Section 83(b) election is and how it can lower your future tax bill. Get clarity on important due dates, filing information, and what to include in form 83(b).

Equity  
January 2026  
How stock options are taxed: A complete guide  
Learn about stock options taxes, including the tax treatment differences between ISOs and NSOs, holding periods, exercising, and the alternative minimum tax.

Founder Education  
October 2022  
How to answer three common employee stock option tax questions  
Learn how to think about answering questions about stock options and taxes—and when you should direct employees to a third-party Equity Tax Advisor.

Taxes  
April 2026  
The alternative minimum tax (AMT), explained  
Learn about the alternative minimum tax (AMT), how it can create a tax liability when you exercise incentive stock options, and how to calculate AMT for your tax return.

Employee Resource Center  
June 2024  
Cashless exercise  
Learn how a cashless exercise of stock options works, including tax implications to consider when exercising ISOs or NSOs.

Equity Education  
July 2022  
The $100K ISO limit  
The ISO $100K limit prevents employees from treating more than $100,000 worth of exercisable options as incentive stock options in a single year. Learn more.