What is the Connecticut economic nexus threshold in 2026?

For 2026, Connecticut's economic nexus threshold is $100,000 in gross sales OR 200 transactions, in effect since 2019-07-01. That dollar figure is only half the rule: the measurement base it applies to and the lookback window it is measured over are set separately by Connecticut and are published by the Connecticut Department of Revenue.

What is the current Connecticut economic nexus threshold?

$100,000 in gross sales OR 200 transactions, effective since 2019-07-01. Sales you make through a marketplace facilitator are excluded from a seller's own threshold count in many states, but that exclusion is a per-state rule rather than a national one — confirm it for Connecticut before you remove marketplace revenue from your tracking.

What counts toward the Connecticut threshold?

It depends on the measurement base Connecticut chose, and states differ. Some count total combined sales of tangible personal property including nontaxable sales (California's $500,000 test works this way), some count only retail sales, and some count only taxable sales (Florida's remote-seller test works this way). Read the base off the Connecticut Department of Revenue's own guidance rather than assuming gross revenue.

What lookback period does Connecticut use for economic nexus?

Lookback windows are not uniform across US states, and four different patterns are in use: a rolling preceding 12 calendar months (Texas), the preceding or current calendar year (California), the immediately preceding four sales tax quarters (New York), and the previous calendar year only (Florida). Because the window decides when you cross on identical revenue, confirm Connecticut's window with the Connecticut Department of Revenue instead of applying a generic rolling-12-month rule.

When do I have to register after crossing the Connecticut threshold?

Registration deadlines after crossing are set by each state separately and are not uniform, so Connecticut's exact date is one to confirm with the Connecticut Department of Revenue. What is consistent across states is the direction of the risk: back-tax exposure accrues on sales made after you crossed, so the cost of registering late grows with every CT order you ship.

Connecticut Sales Tax Economic Nexus Threshold (2026)

Updated 2026-07-20

Reviewed by Nexus by State research team using official state tax sources. Last reviewed 2026-07-20.

Guide content last reviewed: 2026-07-20

If your Thresholds business sells $100,000 or 200 transactions into Connecticut in a calendar year, you have economic nexus and must register, collect, and remit Connecticut sales tax.

Connecticut's economic nexus threshold, in detail

The current Connecticut threshold is $100,000 or 200 transactions, in effect since 2019-07-01.

A threshold is two numbers, not one: the dollar figure above, and the measurement base it is applied to. States do not use the same base — some count total combined sales of tangible personal property including nontaxable sales, some count only retail sales, and some count only taxable sales. That choice can move you across the line months earlier or later on identical revenue, and it is published by the state, not inferable from the dollar amount. Confirm Connecticut’s base with the Connecticut Department of Revenue before you compute. Sales made through a marketplace facilitator are excluded from the seller’s own count in many states but not all — that too is a per-state rule.

Lookback periods: the four patterns states actually use

There is no single national lookback period. Four distinct patterns are in use, and each is written into that state’s own guidance — this site does not publish a lookback period for Connecticut because a wrong window would put you on the wrong side of the line. These four official examples show how far apart the patterns sit:

Preceding 12 calendar months (rolling). Texas: “total Texas revenue greater than $500,000 in the preceding 12 calendar months” — Texas Comptroller publication 94-108, date_retrieved: 2026-07-20.
Preceding OR current calendar year. California: $500,000 in total combined sales of tangible personal property for delivery in California “during the preceding or current calendar year” — so a mid-year surge triggers registration in that same year. CDTFA Wayfair guidance, date_retrieved: 2026-07-20.
Immediately preceding four sales tax quarters. New York: gross receipts over $500,000 and more than 100 sales of tangible personal property delivered into the state, measured across the four preceding sales tax quarters rather than a calendar year — NYS Department of Taxation and Finance, date_retrieved: 2026-07-20.
Previous calendar year only. Florida: taxable remote Florida sales over $100,000 in the previous calendar year, with no transaction-count test — Florida DOR registration guidance, date_retrieved: 2026-06-09.

Registration deadlines after you cross are set separately by each state and are not uniform — confirm both the Connecticut lookback window and the date collection must begin with the Connecticut Department of Revenue.

Common threshold-tracking mistakes

Assuming one lookback window across every state. A seller who tracks all 50 states on a calendar year misses the rolling and four-quarter states entirely, and a seller who tracks everything on a rolling 12 months registers early in the previous-calendar-year states.
Applying the wrong measurement base — counting only taxable sales in a state whose test is total combined sales, or the reverse. Read the base off the state’s own guidance before you build the spreadsheet.
Including collected tax in “gross sales”. The threshold uses pre-tax revenue; double-counting tax in the threshold figure can prematurely trigger registration.
Assuming that falling below the threshold ends the obligation. Once you hold a permit the filing duty attaches to the permit, and whether (and when) you may close the account is a Connecticut DOR determination, not an automatic reset.

Connecticut nexus note

Economic nexus in Connecticut requires BOTH more than $100,000 in gross sales AND more than 200 separate transactions delivered into Connecticut in the prior year. Both thresholds must be met.

What to do next

Read the full Connecticut overview for thresholds, filing frequency, marketplace facilitator rules, and registration links. Use the nexus calculator to check whether you have crossed the threshold. For background on the post-Wayfair economic nexus framework, see the pillar guide.

Thresholds sales tax in other states

Compare Connecticut's thresholds rules with nearby and similar states' thresholds sales tax guides:

Frequently asked questions

What is the Connecticut economic nexus threshold in 2026?: For 2026, Connecticut's economic nexus threshold is $100,000 in gross sales OR 200 transactions, in effect since 2019-07-01. That dollar figure is only half the rule: the measurement base it applies to and the lookback window it is measured over are set separately by Connecticut and are published by the Connecticut Department of Revenue.
What is the current Connecticut economic nexus threshold?: $100,000 in gross sales OR 200 transactions, effective since 2019-07-01. Sales you make through a marketplace facilitator are excluded from a seller's own threshold count in many states, but that exclusion is a per-state rule rather than a national one — confirm it for Connecticut before you remove marketplace revenue from your tracking.
What counts toward the Connecticut threshold?: It depends on the measurement base Connecticut chose, and states differ. Some count total combined sales of tangible personal property including nontaxable sales (California's $500,000 test works this way), some count only retail sales, and some count only taxable sales (Florida's remote-seller test works this way). Read the base off the Connecticut Department of Revenue's own guidance rather than assuming gross revenue.
What lookback period does Connecticut use for economic nexus?: Lookback windows are not uniform across US states, and four different patterns are in use: a rolling preceding 12 calendar months (Texas), the preceding or current calendar year (California), the immediately preceding four sales tax quarters (New York), and the previous calendar year only (Florida). Because the window decides when you cross on identical revenue, confirm Connecticut's window with the Connecticut Department of Revenue instead of applying a generic rolling-12-month rule.
When do I have to register after crossing the Connecticut threshold?: Registration deadlines after crossing are set by each state separately and are not uniform, so Connecticut's exact date is one to confirm with the Connecticut Department of Revenue. What is consistent across states is the direction of the risk: back-tax exposure accrues on sales made after you crossed, so the cost of registering late grows with every CT order you ship.

Sources

date_retrieved: 2026-05-31