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Verified July 2026

How to Calculate Sales Tax in Connecticut, Connecticut

Step-by-step guide with current rates, filing rules, and exemptions verified March 2026

Current Connecticut Sales Tax Rate

Jurisdiction Rate
Connecticut State Sales Tax 6.400%
Total Combined Rate 6.400%
← View full rate breakdown for Connecticut

How to Calculate Sales Tax in Connecticut

  1. 1

    Find the combined rate

    The combined sales tax rate in Connecticut is 6.400%. This equals: Connecticut state rate of 6.400% + County 0.000%.

  2. 2

    Convert the percentage to a decimal

    6.400 ÷ 100 = 0.0640

  3. 3

    Multiply by your purchase amount

    Example: $100.00 × 0.0640 = $6.40 in sales tax

  4. 4

    Add tax to the original price

    $100.00 + $6.40 = $106.40 total cost

What's Taxable in Connecticut?

Most tangible personal property is taxable in Connecticut. Check with the Connecticut Department of Revenue for specific exemption categories.

How to File Sales Tax in Connecticut

  1. 1

    Register for a sales tax permit at the Connecticut Department of Revenue Services

  2. 2

    Collect sales tax on all taxable sales at the applicable 6.400% rate

  3. 3

    File your return Monthly returns due the last day of the following month. File via myconneCT portal. — this is usually done online

  4. 4

    Remit the collected tax to the Connecticut Department of Revenue Services by the due date to avoid penalties

Do You Have Nexus in Connecticut?

Economic Nexus Threshold

If your business has over $100,000 in annual Connecticut sales or 200 transactions, you are required to collect and remit Connecticut sales tax. This applies to out-of-state remote sellers too.

Expert Sales Tax Tips for Connecticut

Out-of-State Sellers

Selling into Connecticut from out of state? Register before you cross the $100,000 threshold to avoid back taxes and penalties.

Frequently Asked Questions

File online at the Connecticut Department of Revenue Services website. Monthly returns due the last day of the following month. File via myconneCT portal. Late filing typically incurs a penalty of 10–25% of unpaid tax.
Prescription drugs are commonly exempt in Connecticut. Check the Department of Revenue for a full exemption schedule.
Late sales tax filing in Connecticut typically results in a penalty of 10–25% of the unpaid tax amount, plus monthly interest charges. File on time to avoid these costs.
Yes. Submit a refund claim to the Connecticut Department of Revenue Services. Refunds are typically processed within 60–90 days of a valid claim.
Yes, if you exceed $100,000 in annual sales or 200 transactions in Connecticut, you must register and collect sales tax — regardless of where your business is based.
← Back to Connecticut Sales Tax Rates Use the Sales Tax Calculator →

Sales Tax Calculator

Using the current combined rate for Connecticut.

Live Tool
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Selected location

Sales tax

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Taxable base:

Total due

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Effective rate:

Rounded to the nearest cent. Tax treatment of shipping and discounts can vary by state.

Open Full Dedicated Calculator
Official Tax Authority

Connecticut Department of Revenue Services

Filing Deadline: Monthly returns due the last day of the following month. File via myconneCT portal.

Visit Official Portal (860) 297-5962

Sitewide Helper

Sales Tax Calculator & Compliance Helper

One compact utility block for tax calculation, reverse calculation, ZIP lookup, nexus checks, exemption guidance, and product taxability.

Advanced Sales Tax Calculator

Estimate tax with shipping, discounts, and exempt subtotal support.

Live Tool
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$

Rate applied

0.000%

Selected location

Sales tax

$0.00

Taxable base:

Total due

$0.00

Effective rate:

Rounded to the nearest cent. Tax treatment of shipping and discounts can vary by state.

Reverse Sales Tax Calculator

Work backward from the total paid to estimate the pre-tax price and tax amount.

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Pre-tax price

$0.00

Tax amount

$0.00

ZIP / City Sales Tax Lookup

Search by ZIP code, city, county, or state to find current combined rates and local breakdowns.

Economic Nexus Checker

Compare your state-specific sales activity against current nexus thresholds using existing site data.

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Nexus estimate

Should I Collect Sales Tax?

A fast intent-matching decision tree for businesses, marketplace sellers, and remote sellers.

Do you sell taxable goods or taxable services?

Do you sell into states outside your home state?

Have you crossed a nexus threshold in a destination state?

Do marketplaces handle most of your sales?

Do you have physical presence in the state?

Decision

Exemption Certificate Finder

Point buyers and sellers toward the right official portal and documentation checklist.

Certificate path

Typical checklist

Product Taxability Checker

Version 1 uses the categories already modeled in the current database and always links back to official verification.

State-aware estimate