Idaho income tax rate for 2025 and 2026: a flat 5.3%

Idaho has one rate, 5.3%, but it applies only to taxable income above an exempt first slice. For 2025 that slice is $4,811 for single filers and married filing separately and $9,622 for married filing jointly, heads of household and surviving spouses; the amounts rise with inflation each year. So the tax is 5.3% of Idaho taxable income minus $4,811 or $9,622, and nothing if that is zero or less.

House Bill 40, signed March 6, 2025, cut the rate from 5.695% to 5.3% retroactive to January 1, 2025 (Idaho Code 63-3024). No rate change passed in 2026, and the Tax Commission’s 2026 withholding tables use 5.3%. The 2026 tax-free amounts come with the 2026 forms.

An Idaho return starts from federal adjusted gross income and uses the same filing status as your federal return. You subtract Idaho items such as Social Security, then the standard deduction, which matches the federal one: for 2025, $15,750 single or married filing separately, $31,500 joint or surviving spouse and $23,625 head of household, plus $2,000 ($1,600 if married) for each person 65 or older or blind. If you itemize, Idaho makes you take out state and local income or sales tax, so the standard deduction can come out ahead.

Every filer also pays a $10 permanent building fund tax, one per joint return, unless their income is below the filing threshold, they receive Idaho public assistance at year end, or they are legally blind.

For example, a single filer with $60,000 of wages for 2025 has $44,250 of Idaho taxable income after the standard deduction. The tax is 5.3% of the $39,439 above $4,811, or $2,090, plus the $10 building fund tax, and the $155 food tax credit brings it to about $1,945.

Idaho followed the July 2025 federal tax law. House Bill 559, signed February 10, 2026, ties Idaho to the Internal Revenue Code as of January 1, 2026, retroactive to 2025, except for bonus depreciation and a research expense rule. As a result Idaho allows the federal deductions for qualified tips (up to $25,000), overtime pay (up to $12,500, or $25,000 joint), car loan interest (up to $10,000) and the extra $6,000 for people 65 or older, on Form 40 line 18. Part-year residents and nonresidents prorate them on Idaho Worksheet 1-A.

Because the law passed in February 2026, people who filed a 2025 return before it got the larger standard deduction automatically, but had to amend to claim the other new deductions. The same federal deductions run through 2028; the Tax Commission will confirm the 2026 treatment with the 2026 forms.

Idaho does not tax Social Security, Railroad Retirement benefits or Canadian Social Security (OAS, CPP and QPP): you subtract the federally taxed part on Form 39R. Pensions, 401(k) plans and IRAs are generally taxed.

A retirement benefits deduction covers some public pensions for people 65 or older, or 62 or older and disabled: the federal Civil Service and Foreign Service retirement systems (not FERS), the Idaho Firefighters’ Retirement Fund and certain Idaho city police funds. PERSI Base Plan benefits do not qualify. For 2025 the maximum is $48,216 single or $72,324 joint, reduced by Social Security and Railroad Retirement benefits received. From 2025, military retirement qualifies for the same deduction if you are disabled, 62 or older, or under 62 and working.

Idaho’s credits come off the tax. The food tax credit and parental choice credit are paid to you even if they are more than you owe.

For 2025 a resident files with gross income of at least $15,750 single, $31,500 married filing jointly or $23,625 head of household (more at 65 or older), and $5 if married filing separately. Part-year residents and nonresidents file if their Idaho-source and resident-period income is more than $2,500. Residents file Form 40; part-year residents and nonresidents file Form 43, with Form 39R or 39NR for adjustments and credits.

2025 returns were due April 15, 2026, and Idaho law sets April 15 for 2026 returns too. You get an automatic six-month extension to file if by April 15 you have paid at least 80% of this year’s tax or 100% of last year’s; no payment is needed for it if the amount would be $50 or less. Idaho does not require estimated tax payments.

Check an Idaho refund with “Where’s My Refund?” from the Tax Commission’s refund page, tax.idaho.gov/refund. It asks for your SSN or ITIN and the original refund amount, with a box for an amended return, and shows the return’s progress through four stages. The tool moves to the Commission’s new Taxpayer Access Point address, tap.tax.idaho.gov, after maintenance on November 6 to 8, 2026.

The Commission says to expect a refund about seven to eight weeks after your e-filed return is acknowledged, or 10 to 11 weeks for a paper return; first-time Idaho filers should add about three weeks. It finds errors on about 25% of returns and may mail an identity verification letter with a short online quiz; once you respond, allow about six more weeks. In 2026 refunds ran much later than usual because of the conformity law and a refund fund shortfall, with most direct deposits arriving July 7 to 15.

You are an Idaho resident if Idaho is your domicile, or if you keep a home here all year and spend more than 270 days in the state. Someone domiciled in Idaho who lives outside it for at least 445 days in a 15-month period can be treated as a nonresident. Residents are taxed on all income, nonresidents only on Idaho-source income, and part-year residents on both for the matching parts of the year.

An Idaho resident who earns wages in Oregon or Utah, which tax income, pays that state’s tax and claims a credit on Form 39R; attach a copy of the other state’s return. Nonresidents cannot claim the credit. Idaho is a community property state, which matters for married couples who file separately or live in different states.