Idaho for retirees: Social Security is exempt, almost nothing else is

If you retire in Idaho, two things decide your state tax bill. The first is good: Social Security and railroad retirement benefits come off in full on Form 39R, Part B, line 7, at any age and any income, so a couple living on $40,000 of Social Security and little else owes Idaho nothing. The second surprises people who move in from a state that leaves pensions alone: PERSI, private pensions, 401(k) and 403(b) distributions, traditional IRA withdrawals and Roth conversions are all taxed at the flat 5.3%. Idaho has no general retirement income exclusion. The one carve-out, the retirement benefits deduction on line 8, reaches only federal Civil Service Retirement System and Foreign Service annuities, military retirement, and a short list of Idaho firefighter and city police pensions, and it shrinks dollar for dollar by the Social Security you receive. What softens the bill is the base: Idaho takes the federal standard deduction, the extra standard deduction for age 65, and the new $6,000 federal senior deduction on its own form, so a retired couple can have $90,000 of federal AGI and still owe the state a few hundred dollars or less.

The rest of this article goes down that list: what comes off, what stays in, the arithmetic of a conversion, where the withholding comes from when nobody is withholding, and the four county property-tax programs that do more for many Idaho seniors than anything on the income tax return.

What Idaho subtracts

Line numbers are from the 2025 Form 39R, revised March 2, 2026. The 2026 form and the indexed 2026 maximums had not been published when this was written.

The Social Security subtraction is of the amount that was taxed federally. If the federal formula put $34,000 of a $40,000 benefit into AGI, $34,000 comes off; the other $6,000 was never in. The result is the same either way: no Idaho tax on the benefit.

The retirement benefits deduction, and who it leaves out

Line 8 is the deduction people hope covers their pension, and for most it does not. The Idaho State Tax Commission’s page lists the qualifying pay: a federal annuity under the Civil Service Retirement System or the Foreign Service Retirement and Disability System, retired military pay, a Firefighters Retirement Fund pension administered by PERSI, benefits for a retired Idaho city police officer whose Idaho employment was not covered by Social Security, and a closed city policemen’s fund that stopped taking members by January 1, 2012. A surviving spouse who has not remarried can claim the deceased spouse’s qualifying benefit. CSRS is not FERS; a federal employee hired after 1983 is almost always under FERS, and a FERS annuity gets nothing on line 8.

The age tests differ by source. For CSRS, Foreign Service and the Idaho funds you must be 65, or 62 and disabled, and file jointly if married. For military retirement, House Bill 40 (2025) widened the door: you qualify if you are disabled, or 62 or older, or under 62 and working with enough income to be required to file a federal return.

Then the maximum, $48,216 single or $72,324 joint on the 2025 form, is reduced by every dollar of Social Security and railroad retirement you received during the year, taxable or not. A married military retiree with a $36,000 pension and $40,000 of Social Security has a cap of $72,324 minus $40,000, or $32,324, and deducts $32,324 of the $36,000. The remaining $3,676 is taxed. The reduction is what keeps the deduction from being a second Social Security exemption for the same household.

The federal senior deduction reaches Idaho

Idaho starts from federal AGI but does not stop there. Form 40 line 16 takes the federal standard deduction, including the extra amounts for age 65 and blindness, and line 18 takes federal Form 1040 lines 13a and 13b together, which is the qualified business income deduction plus the Schedule 1-A deductions for tips, overtime, car-loan interest and the $6,000 per-person senior deduction for 2025 through 2028. House Bill 559 (2026) adopted the Internal Revenue Code as of January 1, 2026, so all of it comes across at the federal amount, phase-out included. A 66-year-old couple with the standard deduction has $32,200 plus two age additions plus $12,000 off their Idaho income before the first dollar is taxed. At 5.3%, the senior deduction alone is worth $636 to that couple.

Roth conversions and QCDs: 5.3% each way

A Roth conversion is a traditional IRA distribution that lands in federal AGI on Form 1040 line 4b, and Idaho has no subtraction for it. Converting $50,000 costs $2,650 of Idaho tax on top of the federal tax, in the year of the conversion. Once the money is in the Roth, qualified withdrawals never appear in AGI and Idaho never sees them. The conversion still raises federal AGI, which can make more Social Security taxable, raise Medicare premiums two years later through IRMAA, and, above $150,000 of modified AGI on a joint return, start phasing out the $6,000 senior deduction that Idaho also honors. Someone planning a move from Idaho to a state with no income tax has a reason to convert after the move rather than before; someone moving the other way has a reason to convert first.

A qualified charitable distribution runs the other direction. A QCD paid straight from an IRA to a charity after age 70½ never enters federal AGI, so it never enters Idaho income either. For a retiree who gives anyway and takes the standard deduction, a $10,000 QCD in place of a $10,000 check saves $530 of Idaho tax that an itemized charitable deduction would not have saved, since most Idaho retirees take the standard deduction once the state income tax is backed out of Schedule A on Form 40 line 14. Required minimum distributions themselves are ordinary Idaho income at 5.3%.

Selling the house, the land or the cattle

Idaho taxes capital gains as ordinary income at 5.3%, with no lower rate. It gives back 60% of the gain on qualifying Idaho property through Form CG: Idaho real property held at least 12 months, tangible property used in a revenue-producing business in Idaho held 12 months, cattle and horses held 24 months, other breeding livestock held 12 months, and Idaho timber held 24 months. Stock, bonds, mutual funds and partnership interests never qualify. For a retiree selling a long-held home, the federal $250,000 or $500,000 exclusion comes first; any gain above it is Idaho real property gain, and 60% of that comes off on Form 39R, Part B, line 10. A retiring farmer or rancher selling land, equipment and a breeding herd will find this deduction does more than any other line on the return.

Withholding when no one withholds

Pension payers and IRA custodians will withhold Idaho tax if asked, and the Department’s own page says the payer may not withhold unless you tell it to. Form ID W-4 sets the amount. Idaho requires no estimated payments from individuals and charges no underpayment penalty, so a retiree with $5,000 of Idaho tax and nothing withheld owes nothing until April 15, 2027. Two things follow. Interest at 6% a year (the 2026 rate; the 2027 rate is to come) runs on anything unpaid after April 15. And the automatic six-month extension to file is only automatic if, by April 15, withholding plus voluntary Form 51 payments cover 80% of the 2026 Idaho tax or 100% of the 2025 Idaho tax. Quick Pay at tax.idaho.gov/quickpay takes a bank payment at any time with no account needed.

The food tax credit and Form 24

Every Idaho resident on the return gets a refundable $155 food tax credit (2025 figure; no change was enacted for 2026), including a couple with no tax at all, which is why the retired couple above ends up with a refund. A resident 65 or older who is not required to file claims it on Form 24 instead of a full return. For 2025 the Form 24 limits were gross income under $17,750 single, $33,100 married with one spouse 65 or older, or $34,700 with both; the form is not available to anyone who had a dependent, filed separately, or received SNAP, was incarcerated or lived in the country illegally during any part of the year. It is due April 15. Residents under 65 who are below the filing threshold use Form 40 to claim the same credit.

Property tax relief: the county, not the return

None of this is on Form 40. Each program is applied for at the county assessor, and the Tax Commission’s property tax division sets the figures. The 2027 program figures, which use 2026 income, were posted in the fall of 2026.

The circuit breaker and the veterans’ benefit require a current homeowner’s exemption and show up as a credit on the December 2027 tax bill. The income test for the circuit breaker counts Social Security and pension income in full, even though the income tax ignores Social Security.

The circuit breaker is the one to check every year. A widow at 72 with $38,000 of income after medical expenses qualifies; the same widow with $41,000 does not, and the limit moves with inflation each year. The deferral is for the homeowner who is house-rich and cash-poor; the tax is not forgiven, only postponed.

Moving in, moving out

Federal law bars a state from taxing the retirement income of someone who no longer lives there. Pension and IRA payments are Idaho income only for the months you were an Idaho resident; a part-year resident reports on Form 43 the payments received while living here. Someone who retires to Idaho from a state that exempts pensions starts paying 5.3% on the pension the month they arrive. Someone who leaves Idaho for a state with no income tax stops. The residency tests are in Moving to Idaho.