---
title: "Total 2026 federal tax as a sole proprietor / LLC vs S-corp vs C-corp for the same profit — SE tax vs FICA vs 21% corporate tax with qualified-dividend double taxation — ranked to the lowest."
method: POST
path: "/v1/business/entity-compare"
tags: ["Business"]
---

# Total 2026 federal tax as a sole proprietor / LLC vs S-corp vs C-corp for the same profit — SE tax vs FICA vs 21% corporate tax with qualified-dividend double taxation — ranked to the lowest.

`POST /v1/business/entity-compare`

## Request

- Base URL: `` (relative, and it does not resolve against the document’s source URL)
- URL: `/v1/business/entity-compare`
- Auth: none declared

Total 2026 federal tax as a sole proprietor / LLC vs S-corp vs C-corp for the same profit — SE tax vs FICA vs 21% corporate tax with qualified-dividend double taxation — ranked to the lowest.

Payment: x402 ($0.10 USDC on eip155:8453). Call unpaid to receive an HTTP 402 with requirements, then retry with the PAYMENT-SIGNATURE header. Method: sole prop: SE + income tax; S-corp: FICA on salary + income tax on passthrough; C-corp: 21% corporate + FICA on salary + income tax on salary + qualified-dividend tax on distribution

## Request body

- object
  - `businessProfit` number, required
  - `ownerSalary` number
  - `filingStatus` 'single' | 'mfj'

## Response `200`

Verified result + provenance (formula, sources, reproducible SHA-256 hash).

## Other responses

- `400`: Invalid input (no charge) — body echoes the JSON Schema.
- `402`: Payment required — PAYMENT-REQUIRED header carries the x402 accepts[] quote.

---

[API](https://skmtc.dev/x402toll/apis/tollbooth-verified-calculators-for-ai-agents.md) · [All operations](https://skmtc.dev/x402toll/apis/tollbooth-verified-calculators-for-ai-agents/llms.txt) · [OpenAPI document](https://skmtc.dev/x402toll/apis/tollbooth-verified-calculators-for-ai-agents/revisions/60cb70a3e1a5?raw)