Quarterly Estimated Tax Calculator — Idaho (2026)
If you earn income in Idaho without withholding — freelancing, contracting, rentals, dividends — the IRS expects payment four times a year, not once. This calculator turns your expected 2026 net profit into a per-quarter number covering self-employment tax, federal income tax and Idaho state tax. Idaho uses a flat personal income tax of 5.30% applied to taxable income after a state standard deduction of $16,100.
Idaho Quarterly Tax Calculator
Gross 1099 income minus business expenses.
2026 due dates and safe harbor
Federal estimated payments are due April 15, June 15, September 15 of 2026 and January 15 of 2027. You avoid penalties by paying either 90% of the current year's liability or 100% of last year's (110% if prior-year AGI exceeded $150,000) — the safe-harbor rule.
Idaho runs its own estimated-payment schedule that usually mirrors the federal dates. On $90,000 of net profit the Idaho portion alone is about $895 per quarter.
Underpayment penalties
The IRS charges interest-style penalties per quarter you fall short, currently around 7–8% annualized. Paying late in the year does not fix an early-quarter shortfall unless you use the annualized income method on Form 2210.
Irregular income is common in tech work around Boise: if Q1 is slow and Q4 is huge, the annualized method usually beats four equal payments.
Paying as a Idaho taxpayer
Pay federally through IRS Direct Pay or EFTPS, and Idaho through the state revenue department's online portal — keep confirmation numbers for both.
Idaho has no separate city or county income tax, so the state figure above is the full sub-federal income tax you pay.
Local and payroll taxes Idaho adds on top
Idaho adds no state-mandated employee payroll deduction beyond FICA, so nothing extra is taken from your gross pay at the state level.
Idaho has no separate city or county income tax, so the state figure above is the full sub-federal income tax you pay.
Nobody withholds these for you when you are self-employed in Idaho. Local wage taxes, city business licences and gross-receipts style levies are yours to register for and remit alongside your quarterly federal and state estimates.
Working across a state line from Idaho
Idaho has no income-tax reciprocity agreements, so if you live here and work across a state line you generally file a nonresident return in the work state and claim a credit at home to avoid double taxation.
Remote and hybrid work complicates this further: most states tax income where the work is physically performed, so a Boise resident spending part of the year at a client site in Washington may owe a nonresident return there. Keep a day-count log if you split time between states.
The rest of your Idaho tax bill
Idaho charges a 6% state sales tax, homeowners pay an average effective property tax of 0.63% of market value, and the minimum wage in force during 2026 is $7.25 an hour.
Few local add-ons, so 6% is close to the effective statewide rate.
Income tax is only one part of a state's take. Idaho recovers revenue through sales and property tax as well, which is why headline income tax rates alone are a poor guide to how far a salary really goes. Idaho exempts Social Security and offers a limited deduction for certain public pensions at 65+.
Idaho vs Washington on the same salary
On a $90,000 salary, a single filer keeps about $68,228 a year in Idaho against roughly $72,145 in Washington — a difference of $3,917, or $326 a month.
Effective combined rates are 24.2% in Idaho and 19.8% in Washington. Set that gap against living costs: index 99 here versus 116 there, with property tax at 0.63% and 0.94% respectively.
Idaho income tax brackets 2026 (single filer)
| Taxable income | Rate |
|---|---|
| $0 and up | 5.30% |