What a mill rate change would mean for your tax bill
Your yearly home tax is assessment × mill rate ÷ 1,000. The numbers below start with Colchester's median home and update as you type. Motor-vehicle and business-property taxes are separate and not included.
Start typing a street address (e.g. "127 Norwich") and choose a match — or skip this step. Until you do, the calculator shows Colchester's median home: a $198,400 assessment — about $283,000 of market value as of October 1, 2021 (the date current assessments were set), or roughly $400,000 in today's market.
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From Step 1, your tax bill, or the town's property lookup. Your assessment is 70% of what the town judged your home was worth at the October 1, 2021 revaluation. Prefilled with the median Colchester home.
FY 2025-26 adopted rate: 29.92.
Starts at the newest revision: +0.51 mills over the current rate, or 30.43 — a figure circulating after the July 28 referendum, not yet confirmed against a published town document. Edit freely as new proposals emerge.
Rates the town has adopted, proposed, or voted on
Round number for comparison — not proposed by anyone
Median Colchester home: a $198,400 assessment. Your own numbers are in the tiles above. The fixed rows compare against the adopted 29.92; the last row uses both rates you set above, so it matches the tiles.
| Rate | Mill rate | Yearly bill | Change | Per month |
|---|---|---|---|---|
| Rates the town has adopted, proposed, or voted on | ||||
| ✓ Current (FY 2025-26), adopted | 29.92 | $5,936 | — | — |
| Newest revision (+0.51 mills)† | 30.43 | $6,037 | +$101/yr | +$8 |
| July 28 proposal (rejected) | 30.97 | $6,144 | +$208/yr | +$17 |
| May 20 proposal (rejected) | 32.01 | $6,351 | +$415/yr | +$35 |
| Round number for comparison — not proposed by anyone | ||||
| Current +0.75 mills | 30.67 | $6,085 | +$149/yr | +$12 |
| Whatever you set above | ||||
| Your "proposed" rate | — | — | — | — |
† The +0.51-mill revision (30.43) is the figure circulating after the July 28, 2026 referendum; it is not yet confirmed against a published town document, and every rate here is editable if you have the official number. Estimates cover the real-estate line of a tax bill only. Individual exemptions and credits (veterans, elderly/disabled homeowner programs, etc.) are not reflected. Motor vehicles are billed separately at the same mill rate. This is an estimate for understanding a proposal's impact — it is not a bill, and the actual FY 2026-27 rate will be set only after a budget passes.
Colchester is re-appraising every property as of October 1, 2026 — the first time since 2021. The new values first affect the tax bill due in July 2027. This is separate from the budget referendum happening now.
Home values have climbed since 2021: the typical Connecticut home is worth about 42% more than in late 2021 (federal house-price index, through early 2026). So most revaluation notices will show a big jump. A big jump in your assessment does not mean a big jump in your tax bill. When every assessment rises, the mill rate gets cut, because the town can only collect what the approved budget allows. It has happened here before: after Colchester's 2006 revaluation, the grand list rose 41% and the mill rate fell from 32.47 to 23.01. What actually moves your bill is how your home's change compares to the town average — and what happens to the budget.
Prefilled with the Connecticut average. Nobody knows their 2026 number yet — this is a what-if, not a prediction.
Uses the assessment from the calculator above (the median Colchester home unless you picked your address or typed your own). The "tax rate" tile assumes all real estate rises by the 42% state average while motor vehicles and business equipment (about 17% of the grand list, and not part of a revaluation) stay flat, with town spending flat: 29.92 ÷ (1 + 0.827 × 0.42) ≈ 22.21 mills. Because that non-real-estate 17% doesn't rise, homes as a group pick up a slightly bigger slice — roughly +5% even for a home exactly at the average — while car taxes fall. The same tilt happened inside real estate at the last revaluation: Colchester's residential values rose about 22.5% in 2021 while commercial rose about 15.8% (CT OPM grand-list components). Individual results vary a lot — but not without limit. Professional assessment standards require revaluations to be uniform (typical homes within roughly 10-15% of the market), so for an ordinary house, market movement alone rarely lands far from the town average: in Westport's 2025 revaluation, values rose about 60% on average, with neighborhood averages between roughly 57% and 66%, and condos moved differently than single-family houses. The homes that swing much harder than that usually changed physically — an addition, major renovation, or new construction. The real FY 2027-28 rate will depend on Colchester's actual 2026 grand list and the budget adopted that year. State average from the FHFA all-transactions house price index for Connecticut, late 2021 to early 2026.
Approximate conversion using the October 1, 2024 net taxable grand list of $1,605,955,411 (CT OPM): one mill raises about $1.61M in taxes.
A cut or addition to the combined town + BOE budgets, to the extent it flows through to the tax levy. Negative for a cut.
The mill rate applies to every property class equally, so each class's share of the grand list is its share of any tax increase. At the current 29.92 mills the whole list raises roughly $48M a year — about $35M of it from homes and apartments. Shares are approximate (class totals are before some exemptions); October 1, 2024 grand list, CT OPM.
| Property class | Share of grand list | Of each $1 raised | Of a $1M increase |
|---|---|---|---|
| Homes & apartments | 73.4% | 73¢ | ≈ $734,000 |
| Motor vehicles | 10.2% | 10¢ | ≈ $102,000 |
| Commercial & other real estate | 9.3% | 9¢ | ≈ $93,000 |
| Business equipment (personal property) | 7.1% | 7¢ | ≈ $71,000 |
An approximation, in both directions: budget changes are not one-to-one with the tax levy (non-tax revenues, state aid, and fund-balance use also move), and the FY 2026-27 levy will be set against the October 1, 2025 grand list, which is not yet published — the GL 2024 total is used here. Median residential assessment: $198,400. The class table above shows how each levy dollar splits across homes, vehicles, businesses, and equipment. For scale, the newest revision's +0.51 mills corresponds to roughly $0.8M more raised by taxes than at the current rate; the July 28 proposal's +1.05 mills was roughly $1.7M.
Your yearly real-estate tax is simple math: assessment × mill rate ÷ 1,000. Your assessment is 70% of what the town judged your home was worth at the last revaluation (October 1, 2021). One mill is $1 of tax for every $1,000 of assessment (glossary).
Where things stand: Colchester's current mill rate is 29.92 (FY 2025-26). The FY 2026-27 budget has not been adopted — proposals were rejected at referendums in May and on July 28, 2026. The May 20 proposal worked out to 32.01 mills and the July 28 revision to 30.97. The newest revision reported since then is a +0.51 mill increase, or 30.43 mills — a figure this page has not yet been able to confirm against a published town document — and the calculator starts there; you can set the "proposed" rate to match whatever the town publishes next.
Typing your address looks up your property in the State of Connecticut's public assessment files — the same data your tax bill is based on. The lookup happens entirely in your browser; nothing you type is stored or sent anywhere.
Vintage. Address lookups use the State of Connecticut's most recent statewide assessment file, which reflects the October 1, 2024 grand list. Colchester last revalued property on October 1, 2021, and between revaluations an assessment changes only through new construction, permits, demolition, or appeals — so for most properties this number is identical to the current (October 1, 2025) assessment. If your property changed recently, use the assessment from your July 2026 tax bill or the town's property lookup (MapXpress), which the assessor's office keeps current.
Revaluation ahead. The town's next revaluation takes effect with the October 1, 2026 grand list (assessor's updates). It will reset every assessment for the tax bills that start July 2027, and the mill rate will be recalculated against the new base. Comparisons on this page apply to bills through FY 2026-27.
Adopted mill rates from town budget books and CT OPM. Rust triangles mark the first year on each new revaluation, when assessments reset. The FY 2026-27 points show the newest reported revision (30.43, unconfirmed) and the two rates rejected at the May 20 and July 28, 2026 referendums — no rate has been adopted for that year.
Uses the address (or median home) from the calculator above. Solid line: computed from assessments actually recorded for the property since the October 1, 2021 revaluation. Dashed line and shaded band: an estimate for the earlier years, because no public statewide file holds a single property's assessment before 2021 — the estimate carries the assessment backwards through each revaluation using measured town-wide factors, and the band is the range those measurements support.
Between revaluations a Connecticut assessment is frozen: it changes only through a permit, an appeal, a demolition, or new construction. So a home’s assessment history is a step function. FY 2007-08, the earliest year charted, already sits inside the October 1, 2006 revaluation, so reaching it from today takes three steps — the revaluations of October 1, 2011, 2016 and 2021 (the five-year cycle in CGS §12-62). Each step below was measured up to three ways from state data, depending on which sources reach that year. Where they disagree, the disagreement is the band on the chart.
The chart above in dollars of the day; this one restates every year in FY 2025-26 dollars using CPI-U, so the years are comparable to each other. The flat gray line is the FY 2007-08 bill expressed in those same dollars: points above it mean the bill outran consumer inflation to that date, points below it mean it did not. Solid, dashed, and shaded have the same meanings as above.
Inflation adjustment: CPI-U, All Urban Consumers, U.S. City Average, annual averages (BLS series CUUR0000SA0) — the same series and the same fiscal-year convention used on the budget trends page, where a fiscal year carries the calendar year it begins in (FY 2007-08 = CY 2007, FY 2025-26 = CY 2025). CPI-U rose 55.3% across this window. CPI-U measures the household basket; deflators built to measure what towns buy (wages, benefits, contracted services) rose faster over the same years, and are set against the budget on the budget trends page — against those, a bill that looks flat here would look lower. The 2025 annual average is BLS’s published figure for that year, computed without October 2025, which was not collected during the lapse in federal appropriations.
Estimated change in the real-estate bill from FY 2022-23 (26.82 mills) to FY 2025-26 (29.92 mills) for every Colchester home with a $100k–$400k assessment and a complete four-year history, using each home's actual assessment in both years. Most homes cluster in the middle; the right tail is larger homes and properties that were improved.
colchester_parcels_gl2024.json (no owner information). Statewide parcel-level collection began with the 2021 grand list, so earlier per-property years are not available in any public statewide dataset — which is why the 18-year chart above is labeled an estimate rather than a record.Data/fetch_ct_sales.py keeps only residential sales of $20,000 or more with an assessed value of $10,000 or more and a sales ratio between 0.15 and 1.50, so the observation counts behind each factor are smaller than that row count; the exact filters travel with the derived file. Colchester's revaluation years are absent from that listing, because OPM does not publish a sales ratio for a town in the year its values reset. Pulled and reduced by Data/fetch_ct_sales.py; the derived file this page loads is colchester_sales_history.json, and the raw rows are kept at Data/ct_sales/colchester_real_estate_sales.csv. Where CT OPM's residential grand list reaches (2011 onward, webp-fgt3) it is used instead of the sales measurement, and the two are compared on the chart's method table.