Not tax advice. Computation tools only. Have a professional review before filing.
openaccountants/skills/ca-estimated-tax-540es.md
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v1California
1---
2name: CA Estimated Tax (540-ES)
3description: Computes California estimated tax payments under Form 540-ES with the 30/40/0/30 installment schedule.
4type: california
5---
6 
7# CA Estimated Tax (540-ES)
8 
9Computes California estimated tax payments under Form 540-ES with the 30/40/0/30 installment schedule.
10 
11## Overview
12 
13This skill is part of the CA Freelance Software Developer tax workflow for tax year 2025.
14 
15## Filing Requirements
16 
17Applicable to sole proprietors and single-member LLCs filing as disregarded entities for federal tax purposes.
18 
19## Computation Rules
20 
21Detailed computation rules and thresholds for tax year 2025. This section will be populated with the full skill content from the production Claude skills.
22 
23## Self-Checks
24 
25- [ ] Verify all inputs against source documents
26- [ ] Cross-check totals with prior year return
27- [ ] Confirm applicable thresholds for TY 2025
28 
29## Disclaimer
30 
31This skill provides computational guidance only. It is not official tax advice. Always have outputs reviewed by a qualified tax professional before filing.

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Quality

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Deep research against tax authority sources. Not yet tested on real data.

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About

Computes California estimated tax payments under Form 540-ES with the 30/40/0/30 installment schedule.

US-CAty-2025

3 of 6 in the US-CA workflow: