The median Idaho homeowner pays $2,038 a year in property tax on a house worth $418,600, which is 0.49 percent of value by Census Bureau figures. County by county, that ratio runs from 0.29 percent in Custer County to 0.78 percent in Nez Perce County. This Idaho property tax calculator takes the market value you enter, multiplies it by your county’s ratio of median tax paid to median home value, and sets the result beside what the typical local owner pays. Enter market value (the figure at the top of your June assessment notice, or a fair sale price), not the net taxable value that remains after exemptions.
The Homeowner’s Exemption: Half Your Value, Up to $125,000
Idaho’s biggest lever on a household bill is the homeowner’s exemption. If a house (manufactured homes included) is your primary residence, the county assessor removes 50 percent of the value of the home and up to one acre of land from the tax roll, with a ceiling of $125,000. That ceiling has applied since 2021, when House Bill 389 lifted it from $100,000. You apply once with the assessor, and the exemption stays until the owner or the use changes.
Idaho Property Tax Calculator (2027)
Choose from all 44 counties, enter what the house would sell for, and see a yearly and monthly figure at the ratio owner occupants there actually pay, set beside the median levy and median value for that county. Built on Census Bureau American Community Survey 2024 five-year estimates.
A planning figure only: your market value times the county's ratio of median tax paid to median owner-occupied value from Census ACS 2024 five-year data. Real Idaho bills apply the combined levy rate of your tax code area to net taxable value, meaning market value minus the homeowner's exemption (50 percent of a primary residence and up to one acre, capped at $125,000), then subtract any state Homeowner Tax Relief credit. It does not model the Property Tax Reduction program or the disabled veteran benefit (up to $1,500 each), fees such as solid waste, or new voter-approved levies. Check your value with the county assessor and your bill with the county treasurer.
A common mistake online is to describe this as half of the first $125,000. It is half of the whole value, capped at $125,000, so the cap starts to bite at a $250,000 home:
- A $200,000 home: $100,000 exempt, $100,000 taxable.
- A $400,000 home: half would be $200,000, so the cap applies, $125,000 exempt, and $275,000 taxable.
At the statewide median of $418,600 the exemption covers about 30 percent of value, but on an $800,000 home it covers only 15.6 percent, so expensive homes carry a higher effective rate than their county’s ratio. And a rental or second home gets no exemption at all: the same $400,000 house held as a vacation cabin is taxed on the full $400,000, about 45 percent more than the homestead under an identical levy. That matters in Blaine, Teton, and Valley counties, where second homes are common.
The newest change came in 2026. House Bill 843, effective January 1, 2026, ended proration of the exemption. Filing any time before close of business on the last business day of the year now earns the full exemption for that year; if you file after the second Monday in July, your full value stays on the roll but the county cancels the matching amount of tax.
Why the Census Ratio Differs From the Levy on Your Notice
Idaho publishes its rates as a percentage of taxable value, meaning market value minus exemptions. The ratios in this calculator are measured against market value instead, and they come from owner-occupied homes, nearly all of which carry the homeowner’s exemption. The exemption is therefore already inside each ratio. That is one reason the Tax Commission’s statewide 2025 rate of 0.552 percent (all property, after state relief) sits above the 0.49 percent Census figure for homeowners. Use the county ratio for a quick market value estimate; use your tax code area’s levy and net taxable value when you want the exact bill.
County Ratios From Custer to Nez Perce
On the Census Bureau’s 2024 five year estimates, Nez Perce County has the highest ratio at 0.78 percent, followed by Power at 0.70, Bannock and Latah at 0.64, and Jerome at 0.63. Custer is lowest at 0.29 percent, then Valley at 0.30, Teton at 0.31, and Idaho County at 0.32. Half the counties fall at or below 0.44 percent.
Ratios and bills tell different stories. Blaine County, home to Sun Valley and Ketchum, has a modest 0.38 percent ratio, yet its $735,300 median value produces the largest median bill in the state, $2,778. Ada is next at $2,655. The smallest median bill belongs to Clark County, at $713.
Two examples run through the calculator:
- Ada County, $500,000 home: $500,000 times 0.52 percent is $2,600 a year, or $216.67 a month, $55 under the county’s $2,655 median.
- Kootenai County, $450,000 home: $450,000 times 0.44 percent is $1,980 a year, or $165 a month, $287 under the $2,267 median.
Put one $400,000 house at both ends of the range and it costs $3,120 a year at the Nez Perce ratio against $1,160 at the Custer ratio.
Who Sets the Levy, and the State Money That Trims It
Every parcel sits in a tax code area, a unique mix of taxing districts such as the county, a city, a school district, a highway district, and fire, library, or sewer districts. Idaho has several thousand of these combinations. Each district adopts a budget, divides the property tax portion by the taxable value inside its borders, and that quotient becomes its levy rate. Your bill is the sum across all of them. The Tax Commission oversees the process and approves levy rates, but it does not collect the tax.
Idaho limits the dollars, not the rate. Under Idaho Code 63-802, a district can raise the property tax part of its budget by no more than 3 percent a year, plus growth from new construction (counted at 90 percent since 2021) and annexation, unless voters approve more. When values climb faster than budgets, levy rates fall.
Since 2023 the Legislature has also sent state money into local bills. House Bill 292 (2023) and House Bill 521 (2024) set up two channels: School District Facilities Funds that school districts must apply against bond, supplemental, and plant facility levies, and Homeowner Tax Relief, a line item credit on primary residence bills against non-school levies. For 2025, the Tax Commission counted $215.2 million in school levy reductions and $112.8 million in homeowner credits, cutting $2.502 billion in budgets to a final $2.174 billion paid. Owner-occupied homes carried 44.3 percent of 2025 taxes, down from 51 percent in 2022.
Relief You Must Apply For by April 15
Beyond the exemption, the Tax Commission runs three programs through county assessors:
- Property Tax Reduction: $250 to $1,500 off the tax on your home and up to one acre if you are 65 or older, blind, widowed, disabled, a former POW or hostage, or a motherless or fatherless child under 18. For 2027 taxes, your 2026 income after medical expenses must be $40,030 or less. Apply between January 1 and April 15, 2027.
- Disabled veteran benefit: up to $1,500 off for veterans the VA rates 100 percent service-connected disabled or pays at the 100 percent rate for individual unemployability. There is no income test, and the April 15 window is the same.
- Deferral: qualifying owners can postpone the tax on the home and up to one acre; apply from January 1 through the first Monday in September.
June Assessment Notices and the Fourth Monday Deadline
Idaho assesses at 100 percent of market value as of January 1, and assessors revalue every year. Notices for the main roll go out no later than the first Monday in June, which is June 7, 2027. If the market value looks wrong, talk with the assessor’s office first, then file a written appeal with the county Board of Equalization by 5 p.m. on the fourth Monday in June: June 28, 2027.
If the board rules against you, you have 30 days to go to the Idaho Board of Tax Appeals or district court. The Board of Tax Appeals charges no filing fee, you do not need a lawyer, and the notice of appeal goes to your county auditor, one per parcel.
December 20, June 20, and the Three Year Tax Deed
County treasurers send bills by the fourth Monday in November. You can pay the full amount by December 20 or pay half by December 20 and the second half by June 20 of the following year. Miss the first half and the county adds a 2 percent late charge plus interest at 1 percent a month starting January 1. When taxes stay unpaid for more than three years, the county takes the property by tax deed and can sell it.
What 2027 Brings, and When These Ratios Refresh
Several things change your 2027 bill before it arrives. District budgets are set over the summer, the state decides each year how much relief money flows to schools and homeowner credits, and HB 843 now lets late filers still claim the full exemption. Our county ratios rest on the ACS 2024 five year file, which pools survey answers collected over 2020 through 2024; each December the Census Bureau releases a newer file, and this calculator switches to it.
Sources: US Census Bureau American Community Survey (2024 five-year release), tables B25077 and B25103; Idaho State Tax Commission homeowner program pages, April 7, 2026 guidance memo on House Bill 843, and “Market Values and Property Taxes for 2025” (December 22, 2025); Idaho Code 63-602G, 63-724, 63-802, and 63-903; Idaho Board of Tax Appeals. Questions about value or exemptions go to the county assessor; questions about the bill or payment go to the county treasurer.