Idaho sales tax is filed online through TAP (Taxpayer Access Point), the State Tax Commission's portal, on the Sales and Use Tax Return (Form 850). Monthly returns are due by the 20th of the following month, and a return is required every period, even with no sales. The Commission says it no longer mails paper returns, so a regular seller's permit holder files online in TAP.
This guide covers who files and how often, how to file in TAP, how to handle Idaho's resort-city local taxes, how to report no sales, how to amend a return, how to pay, and what late filing costs.
This article is educational information, not tax advice. Filing rules, thresholds, and penalties can change, so confirm current requirements with the Idaho State Tax Commission before you file.
Idaho sales tax filing at a glance
- Who administers it: Idaho State Tax Commission.
- Online portal: TAP, at tax.idaho.gov/gototap. A TAP account is free.
- Return: Sales and Use Tax Return, Form 850.
- Tax rate: 6% state sales tax, and 6% use tax.
- Filing frequency: Monthly, quarterly, semiannual, or annual. The Commission sets you up on one of them.
- Due dates: Monthly returns by the 20th of the following month. If the 20th falls on a weekend or holiday, the return and payment are due the next workday.
- Zero returns: Required for every period if you have a seller's permit.
- Payment: Bank account (ACH debit), card, ACH credit, check, or in person.
- Economic nexus: Sales into Idaho above $100,000 in the current or previous year for a retailer without a physical presence in the state.
Who has to file, and how often
Almost everyone selling goods or taxable services in Idaho needs a seller's permit, collects sales tax, and files a return. The Commission's permit page also lists out-of-state retailers whose sales into Idaho exceed $100,000 (economic nexus), and out-of-state retailers with more than $10,000 of sales into Idaho through a retail referral agreement (click-through nexus). For online sellers, the Commission's guide describes the $100,000 test as sales in Idaho exceeding $100,000 in the current or previous year. Our Idaho sales tax guide covers registration and nexus in more detail. For a product-level example, see our post on Idaho digital products sales tax.
Two groups get different treatment. An Idaho resident who qualifies for the small seller exemption does not have to file, but if cumulative sales in a calendar year exceed $5,000 the seller no longer qualifies and must begin collecting sales tax and apply for a permit within 30 days. A seller that sells only through third-party sites that register with the Commission as marketplace facilitators may not need a permit at all, and the Commission tells sellers to verify that the marketplace is reporting their sales.
With a regular seller's permit, your filing schedule depends on how much you sell:
| Frequency | Who it fits | Due date |
|---|---|---|
| Monthly | Most retailers | The 20th of the following month |
| Quarterly | Retailers who owe less than $750 tax per quarter | Within 20 days after the end of the quarter |
| Semiannual | Distributors and wholesalers with only a few sales, by application | July 20 and January 20 |
| Annual | Distributors and wholesalers with only a few sales, by application | January 20 |
Sales tax is due on the accrual method of accounting, so you report tax on a sale in the period you made it, even if your customer has not paid you by the time the return is due.
Before you start: get into TAP
You need a seller's permit before you can file. Our sales tax permit overview explains the general process. Permit holders who do not yet have a TAP account can create one for free at tax.idaho.gov/newTAP. TAP is also where you pay, schedule payments, and see your account history.
Before filing, gather your total sales for the period, your nontaxable sales, and support for anything you exclude. For wholesale sales, see our Idaho resale certificate guide for what to collect from buyers.
Step-by-step: filing a return in TAP
- Log in to TAP and, on the Summary tab, find your Sales and Use tax account. Click File/View Returns.
- Find the period you are filing and click File Now. Read the instructions and click Next.
- Answer the account questions. TAP asks whether you are canceling your permit or changing your address.
- Enter your return information. Form 850 asks for total sales, including cash and credit sales even if you have not been paid, and nontaxable sales such as sales shipped or delivered outside Idaho, sales to exempt entities, wholesale sales, and repair labor. It also has a line for items subject to use tax. Do not report sales that a registered marketplace facilitator or short-term rental marketplace already reports for you.
- Use Line 7 only for adjustments. The form instructions say to provide a letter explaining any adjustment and that adjustments are subject to approval. Prior payments should not be entered as adjustments.
- Review, pay, and submit. If you owe nothing, click Submit. If you owe tax, choose how to pay. TAP lets you file and pay in the same process for most returns. You should see a confirmation screen, and if you do not, the Commission says it did not receive your submission.
Returns and payments are on time if submitted by 11:59 p.m. Mountain Time on the due date, and you can file up to 90 days before the due date.
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Resort-city local taxes and rate pitfalls
Idaho's state sales tax rate is 6%. The Commission also lists a number of resort cities, including Ketchum, McCall, Sandpoint, and Sun Valley, that have a local sales tax in addition to the state tax. Some apply it to everything subject to state sales tax, and others limit it to lodging, alcohol by the drink, and restaurant food. The Commission tells sellers to contact the city directly with questions about its local tax, so confirm how a local tax applies to your sales, and how it is reported, before you file. Our Idaho sales tax calculator can help you check rates by location.
Form 850 counts sales with an Idaho destination as sales, whether they originate in Idaho or outside it. Goods shipped directly to a destination outside Idaho are a nontaxable sale, and the Commission says to keep records that support that treatment.
Due dates and the weekend rule
Idaho's due dates depend on your filing frequency, and you can compare them with other states on our Idaho sales tax due dates page:
| Period | Due date |
|---|---|
| Monthly | The 20th of the following month (a July return is due August 20) |
| Quarterly | Within 20 days after the end of the quarter |
| Semiannual | July 20 and January 20 |
| Annual | January 20 |
For monthly returns, the Commission says that when the 20th falls on a weekend or holiday, the return and payment are due the next workday. Each return shows the period covered and its due date, so check the return in TAP for the exact date, and confirm the weekend treatment for quarterly, semiannual, and annual returns with the Commission. TAP can also send due-date reminders.
Filing a zero return
You must file even if you had no sales. The Commission says you must file a return if you have any type of seller's permit, even if you do not make any sales, and the Form 850 instructions say to file a return for each reporting period, even when no tax is due. The only exception the Commission names is an Idaho resident qualifying for the small seller exemption. The Commission also says that if you report $0 sales for 12 months in a row, it will cancel your permit, and a cancelled permit cannot be used to make sales or buy goods for resale.
Amending a return
You can amend a Form 850 in TAP. From the Returns screen, click View or Amend Return next to the return, then click Amend and change the fields that need changing. Leave the adjustment field set to No if you only need to amend. TAP may ask for a reason for the amendment and supporting documents on the Amended Return Uploads screen, then walks you through reviewing the amount owed and paying, if any. The Commission announced this online option on July 30, 2026. Before then, amended returns were submitted on paper.
Payment methods
- Bank account (ACH debit): No service fee.
- Credit or debit card: The E-Pay page lists a service fee of 2.5% of the payment, processed by PayIt, for American Express, Discover, MasterCard, and Visa.
- ACH credit: Accepted, with more information on the Commission's ACH credit page.
- Check or in person: The Commission also accepts payments by mail and at its offices.
Idaho law requires ACH debit or ACH credit for payments of $100,000 or more (individual income tax excepted). If you do not use these methods when required, the Commission says it can charge interest and a $500 penalty. You can schedule payments in TAP up to 90 days in advance for permit taxes. Sellers with a debit block on their bank account need to authorize the Commission's debits, using the number on its E-Pay page.
Penalties and interest for late filing
The Commission lists these penalties:
- Return not filed on time: 5% of the tax due for each month the return is late, up to 25%.
- Return filed but tax not paid: 0.5% of the tax due for each month the tax is late, up to 25%.
The Commission notes that no penalty is due if no tax is due, that the minimum penalty is $10, and that even a return or payment one day late owes the entire month of penalty.
Interest runs on overdue tax from the original due date of the return until the tax is paid. The Commission's interest rate table lists 6% per year for 2026. Payments are applied in this order: bad check fees, interest, tax, then penalty.
Common mistakes to avoid
- Skipping zero returns. Every period on a seller's permit needs a return, even with no sales.
- Reporting marketplace sales twice. Do not report sales that a registered marketplace facilitator already reports for you.
- Entering prior payments as adjustments. Line 7 is for adjustments that you explain in a letter, and they are subject to approval.
- Ignoring resort-city taxes. Some cities add a local sales tax on top of the 6% state rate.
- Filing or paying one day late. The Commission charges the entire month of penalty.
- Missing the ACH requirement. Payments of $100,000 or more must use ACH debit or ACH credit.
If you receive a sales tax notice
A missed or late return often leads to a letter. Our Idaho sales tax notices guide explains what notices from the Idaho State Tax Commission mean, why businesses usually receive them, and what to do next. It also points to how to ask for penalty relief where the state publishes a process. Check the date on the notice, match it to your filing period, and follow the instructions on the notice itself.
More state filing guides
Filing in more than one state? These step-by-step guides cover the portals, due dates, and penalties in other states. See them all in our state-by-state guide to filing sales tax online.
- How to file Washington sales tax online
- How to file Utah sales tax online
- How to file Nevada sales tax online
Let Kintsugi file for you
If you sell in Idaho and other states, Kintsugi's sales tax filing software prepares and files returns on each state's assigned schedule and remits payment. Monitoring across every US state is free, so you know when you cross a threshold. Filing starts at $75 per filing, with no per-state subscription. See pricing, start free, or book a demo.
Frequently asked questions
Can I file Idaho sales tax online for free?
Yes. A TAP account is free, and paying by bank account (ACH debit) has no service fee. The Commission lists a 2.5% service fee for card payments.
What form do I use to file Idaho sales tax?
Sales and Use Tax Return, Form 850, filed online in TAP.
When is Idaho sales tax due?
Monthly returns are due by the 20th of the following month. Quarterly returns are due within 20 days after the end of the quarter, semiannual returns by July 20 and January 20, and annual returns by January 20.
Do I have to file if I had no sales?
Yes, if you have a seller's permit. Idaho requires a return for each reporting period even when you made no sales. The exception is an Idaho resident who qualifies for the small seller exemption.
What is the economic nexus threshold in Idaho?
For a retailer without a physical presence in Idaho, sales in Idaho above $100,000 in the current or previous year. A separate $10,000 threshold applies to sales through a retail referral agreement.
What if I miss the deadline?
File and pay as soon as possible. The penalty for a late return is 5% of the tax due per month up to 25%, plus interest, and even one day late owes a full month of penalty.
Sources
Checked September 29, 2026.
- Idaho State Tax Commission, Sales Tax: Filing and Paying
- Idaho State Tax Commission, Form 850 Instructions, Sales and Use Tax Return
- Idaho State Tax Commission, Filing and Paying in TAP
- Idaho State Tax Commission, Amended 850 Filing Now Available in TAP
- Idaho State Tax Commission, E-Pay
- Idaho State Tax Commission, Interest Rates
- Idaho State Tax Commission, Sales and Use Taxes: Basics Guide
- Idaho State Tax Commission, Who Needs a Seller's Permit?
- Idaho State Tax Commission, Online Sellers Guide
- Idaho State Tax Commission, City Sales Taxes
