Sales Tax

What Salestax is for

"What's the sales tax on this in California?", "which state has the cheapest sales tax?", "if this total already includes tax, what was the price before?" — a US sales-tax calculator bundling real, current rates rather than guessing or inventing them.

What it does

calculate_tax computes the approximate tax and total on a purchase for a US state, using either the state's average combined (state + local) rate or a specific local rate you supply for an exact address. state_rate and average_combined_rate return one state's statewide rate and average combined rate directly. compare_states lines up 2-20 states' tax on the same purchase amount, ranked cheapest to most expensive. no_sales_tax_states lists the five states with no statewide sales tax — Alaska, Delaware, Montana, New Hampshire and Oregon — and notes that Alaska is a partial exception since many of its municipalities still levy their own local sales tax. reverse_calculate backs a pre-tax price and the tax amount out of a tax-inclusive total at a known rate. multi_item_total totals a shopping cart, applying tax only to items you mark taxable, so you can model a state's grocery, clothing or other exemptions. exemption_note gives general categories commonly exempted or reduced somewhere in the US — a pattern across states, not a definitive per-state legal database. states_list ranks all 50 states plus DC by combined rate, and glossary defines nexus, use tax, combined rate, origin- vs. destination-based sourcing, special districts and sales tax holidays.

Where the numbers come from

Every statewide, average local and average combined rate is taken directly from the Tax Foundation's "State and Local Sales Tax Rates" report (midyear 2026 update) — the standard, widely cited source for this data — not estimated or invented. Average local rates are population-weighted averages across a state's cities and counties; they are real numbers, but they are averages, and the actual rate at a specific address regularly differs because US sales tax is set by a patchwork of state, county, city and special-purpose district jurisdictions.

What it is not

Not tax advice, and not a substitute for checking your state or local revenue department for an exact rate at a specific address, or for a definitive answer on whether a specific item is exempt in a specific state. Supply your own known local rate wherever precision matters.

Sales Tax — Privacy Policy

Effective 25 September 2026. Unify Dynamics LLC ("we", "us"), Menlo Park, California.

What Salestax is. Salestax is a connector (an MCP server and REST API) that AI assistants and personal agents call on your behalf for a US sales-tax calculator bundling real state and average combined sales-tax rates — tax and total calculations, state comparisons, reverse (tax-inclusive) calculations, a cart total, and reference notes. You interact with your assistant; the assistant sends us only the arguments needed for that one calculation.

What we receive. The arguments of each tool call — a state name, a purchase amount, an optional local rate you supply, a cart of item names/prices, or a glossary term — the technical headers needed to serve the request (an IP address or a client identifier supplied by the assistant, and a Pro API key if you have one), and standard server logs.

Everything is computed locally from bundled reference data and nothing is stored. No request is forwarded to any third party, including any tax authority or point-of-sale system — there is no upstream call at all — and no purchase amount, item, or query is logged in request bodies, recorded, or used to train anything.

What we do not receive or store. We do not receive your conversation with the assistant, your name, your actual address, or your purchase history, and we do not build a profile from your queries: each request is answered independently and nothing carries over between requests. Rate-limit counters (a client identifier and timestamps) are held in memory for at most 24 hours. Hosting-provider access logs, which contain IP addresses and request paths but not request bodies, are retained for up to 30 days for security and abuse prevention.

Sub-processors. None — every calculation runs locally on the server against bundled reference data. Hosting: Vercel (United States regions).

Legal bases and your rights. Our processing is necessary to provide the service you request through your assistant. Because we store no personal data beyond short-lived logs, requests to access, correct or delete personal data are usually satisfied automatically; you can still contact agent@connectorbay.com and we will respond within 30 days. We do not sell or share personal information and do not use your data to train models.

Children. Salestax is a general-audience service operated by the adult using the assistant.

Changes. We will post changes here with a new effective date.

Sales Tax — Terms of Service

Effective 25 September 2026. These terms govern use of the Salestax connector ("the Service") operated by Unify Dynamics LLC ("we", "us").

1. The Service. Salestax returns US sales-tax calculations and reference data — statewide and average combined sales-tax rates by state, tax and total calculations, comparisons, reverse (tax-inclusive) calculations, a cart total, and general exemption-category notes. It is accessed through an AI assistant or directly over MCP or HTTP.
2. Not tax advice; rates are approximations unless you supply your own. State rates are current as of the effective date above, sourced from the Tax Foundation. Average combined (state + local) rates are population-weighted averages and may differ, sometimes substantially, from the rate at a specific address — local sales tax in the US is set by a patchwork of state, county, city and special-purpose district jurisdictions. Exemption-category notes are a general pattern, not a definitive legal statement of what is exempt in any specific state. Nothing in this Service is legal, tax or accounting advice; consult a qualified professional or your state/local revenue department for anything that depends on an exact figure or legal determination.
3. Accuracy over time. Sales-tax rates change. This Service reflects the rates in the build noted in its own data (Tax Foundation, midyear 2026) and may not reflect subsequent changes until updated.
4. Acceptable use. Automated use within the published rate limits is welcome.
5. Availability. The Service is provided "as is" without warranty. We may change, limit or discontinue it at any time.
6. Data. Our Privacy Policy describes what we process. In short: your inputs are used only to compute one response, and nothing is stored.
7. Pro keys. Optional Pro API keys are issued at our discretion, are personal to the holder and may be revoked for abuse.
8. Liability. To the fullest extent permitted by law, Unify Dynamics LLC is not liable for any loss, tax underpayment, overpayment, or penalty arising from reliance on this Service's calculations or reference data. Our total liability is limited to US $100.
9. Governing law. California law; venue in San Mateo County, California.
10. Contact. Unify Dynamics LLC · agent@connectorbay.com · https://connectorbay.com/salestax

Sales Tax support

Email agent@connectorbay.com. We answer within two business days.

• MCP endpoint: https://salestax.connectorbay.com/mcp
• REST API: https://salestax.connectorbay.com/openapi.json
• Live status: https://salestax.connectorbay.com/health

When you report a problem, include the question you asked your agent, roughly when, and which agent you used (for example Claude, ChatGPT or Gemini). Never send us passwords, account numbers or ID numbers. Sales Tax never asks for them.