The Formula in 60 Seconds
Connecticut property tax = (mill rate × 70% of fair market value) ÷ 1,000.
Every Connecticut municipality sets its own mill rate annually. A mill is one dollar of tax per $1,000 of assessed value. Assessment is fixed at 70% of fair market value as determined by the town's most recent revaluation (every 5 years per state law).
Why the Same Home Costs Different Amounts
A $500,000 fair market value home has an assessed value of $350,000 (70%). At different mill rates:
- Greenwich (11.59 mills): $4,057/year
- Westport (16.86 mills): $5,901/year
- Branford (27.92 mills): $9,772/year
- Hamden (55.48 mills): $19,418/year
- Hartford (68.95 mills): $24,133/year
Same house. Same value. Five-fold range in annual tax bill.
Why Mill Rates Vary So Much
Three drivers:
- Grand list size. Towns with broad commercial tax base (corporate parks, retail, industrial) spread the tax burden. Towns that are almost entirely residential push more burden onto homeowners.
- Budget level. Towns with high municipal employee counts, pension obligations, and program spending need more revenue.
- Assessed value level. A town where the median assessed value is $1.4M (e.g., Greenwich) doesn't need a high mill rate to fund its budget. A town where median assessed value is $200K must charge dramatically higher rates to fund similar services.
What Buyers Should Verify
Before offering on any CT property:
- Pull the property's current tax bill directly from the town assessor — don't trust the MLS
- Check whether any current exemptions (veteran, elderly, disability) won't transfer to you
- Check when the next town-wide revaluation occurs — your bill could change
- Estimate your annual tax: assessed value × current mill rate ÷ 1,000
The Bottom Line for Cross-Town Comparisons
Don't compare mill rates alone. Compare effective annual tax bills on similar-quality homes. A 12-mill Greenwich estate and a 39-mill New Haven multifamily may have comparable absolute tax obligations on dramatically different price points.