Filling out the 3-NDFL declaration online: instructions for with examples

Filling out the declaration 3-NDFL online has become a mandatory skill for those who want to return a tax deduction, declare income from the sale of property or confirm expenses for individual entrepreneurs. Since 2026, the Federal Tax Service (FTS) has simplified the process: now the entire procedure can be completed without leaving home - through Taxpayer personal account, mobile application or specialized programs like Declaration 2026. But even with the simplification of the interface, many encounter errors: from incorrectly indicating the BCC to missing required fields, which leads to denial of deductions or fines.

In this article we will analyze step-by-step filling out 3-NDFL online for different situations: return of deductions for treatment/training, sale of a car or apartment, income from freelancing. We’ll show you screenshots of current forms and tell you about new income and deduction codes in 2026, and also warn against typical mistakes due to which the Federal Tax Service may return the declaration for revision. If you've never dealt with tax reporting, don't worry: our guide is suitable even for beginners.

1. Who and when should submit 3-NDFL online in 2026

Declaration 3-NDFL Individuals are required to file in three main cases:

• 💰 Received incomefrom which tax is not withheld (sale of property, rental of an apartment, winnings, gifts over RUB 4,000 from non-close relatives).
• 📑 They want a tax refund (for treatment, training, purchase of housing, charity, etc.).
• 🏢 Individual entrepreneurs (IP) on the general taxation system (OSNO).

Deadlines for delivery depend on the goal:

• 📅 Until April 30 - for declaring income (for example, after the sale of a car or apartment, ownership of which is less than 3/5 years).
• 💸 Anytime — to submit for deduction (but tax refunds can only be made for the last 3 years).

⚠️ Attention: If you sold property below the cadastral value (for apartments) or below 70% of the market value (for cars), the tax office may charge additional personal income tax. Effective in 2026 new odds to calculate the minimum income.

Example: You sold an apartment for 2 million rubles, but its cadastral value is 3 million rubles. The tax office will calculate your income as 3 million × 0.7 = 2.1 million rubles and will charge an additional 13% of the difference (100,000 rubles). To avoid this, prepare in advance documents confirming the real price of the transaction (appraiser’s report, agreement with the realtor).

2. Methods for filling out 3-NDFL online: which one to choose

In 2026, taxpayers have 4 official ways fill out and submit the declaration remotely:

Method	Pros	Cons	Link
Taxpayer's personal account (LKN)	✅ Auto-fill part of the data ✅ Free ✅ Electronic signature through State Services	❌ Interface may change ❌ No tips for difficult cases	lkfl.nalog.ru
Declaration 2026 program	✅ Works offline ✅ Detailed tips ✅ Check for errors	❌ Need to download and update ❌ A little difficult for beginners	Download from the Federal Tax Service website
Mobile application "Taxes FL"	✅ Convenient from your phone ✅ Scanning documents ✅ Status notifications	❌ Limited functionality ❌ Not all deductions are supported	App Store / Google Play
Via bank (SberBank Online, Tinkoff)	✅ Integration with your personal account ✅ Pre-filled account data	❌ Not all banks support ❌ Limited types of deductions	—

For most users, the best option is Taxpayer personal account. It is free, does not require software installation and automatically pulls up income data from 2-NDFL certificates. However, if you have a complex situation (such as multiple sources of income or unusual deductions), it is better to use the program Declaration 2026 — it allows detailed calculations.

3. Step-by-step instructions: how to fill out 3-NDFL in your Personal Account

Let's look at the process using an example refund of tuition deduction (the algorithm is similar for other types of deductions).

Step 1. Authorization and selection of declaration

1. Go to Taxpayer personal account through Public services.

2. From the menu, select Life situations → Submit a 3-NDFL declaration.

3. Indicate the year for which you are filing a return (for example, 2023 for return in 2026).

Step 2. Filling out income data

The system will automatically pull up information from references 2-NDFL, which the employer sent to the Federal Tax Service. Check:

• 📌 Amount of income (must match the certificate from the accounting department).
• 📌 Revenue code (for example, 2000 - salary, 1520 - dividends).
• 📌 Amount of tax withheld (13%).

If there is no data, add it manually using the button Add income, indicating:

• Source of payment (name of organization or TIN).
• Month of income.
• Amount and income code (a list of codes is in Federal Tax Service directory).

Step 3. Specifying deductions

To deduct tuition:

1. Go to the section Deductions → Social deductions.

2. Select the type of deduction: Training (code 126).

3. Fill in information about the educational institution (TIN, name, license) and the amount of expenses (maximum 120,000 ₽ per year, including other social deductions).

4. Attach scans of documents:

• 📄 Agreement with an educational institution.
• 💳 Checks or payment orders.
• 🎓 License of an educational institution (if the TIN is not specified).

Step 4. Verification and submission

Before sending, the system will show:

• 🔍 Amount to be refunded (if you are applying for deduction).
• 🔍 Amount to be paid additionally (if you declare income).
• 🔍 Preliminary errors (for example, mismatch of the organization’s TIN).

If everything is correct, sign the declaration qualified electronic signature (via Public services) and send. Save your admission receipt - you will need it to track your status.

4. Typical mistakes when filling out 3-NDFL online

According to statistics from the Federal Tax Service, 30% of declarations are returned for revision due to errors. The most common:

• 🔢 Invalid KBK (budget classification code). In 2026, the KBK will operate for personal income tax 18210102010011000110. If you enter the old code, the money will go to the wrong destination.
• 📅 Dates do not match in the declaration and payment documents. For example, a tuition check is dated 2023, but the declaration indicates 2026.
• 🏠 Incorrect calculation of deductions when selling property. Many people forget that for apartments purchased before 2016, the minimum tenure is 3 years, and for cars - 3 years (if the cost is above 250,000 rubles).
• 📝 Lack of supporting documents. Without contracts, checks or certificates, the Federal Tax Service will refuse the deduction.

⚠️ Attention: If you sold a car for less than 70% of its market value (as assessed by the tax authorities), you will have to pay personal income tax on the difference. For example, if you sold a car for 500,000 rubles, and the tax authorities valued it at 1 million rubles, the income will be 700,000 rubles, and the tax is 13% of this amount (91,000 rubles). To avoid this, order an independent appraisal before the transaction.

Another common mistake is incorrect indication of taxpayer status. For example, if you are a tax resident of the Russian Federation (live in the country for more than 183 days a year), but check the “non-resident” box, the personal income tax rate will increase from 13% to 30%. Check this item under Information about the declarant.

What to do if the tax office returned your return?

If the Federal Tax Service has detected errors, you will receive a notification in your Personal Account with a list of shortcomings. Correct them and resubmit your return. The correction period is 5 working days from the date of notification. If you miss this deadline, you may be charged a fine (5% of the tax amount for each month of delay, but not less than 1,000 rubles).

5. Features of filling out 3-NDFL for different situations

The algorithm for filling out the declaration depends on the purpose. Let's look at the nuances for the most common cases.

📚 Deduction for tuition (yours or your children’s)

Maximum deduction amount - 120,000 ₽ per year (including other social deductions). For teaching children the limit is - 50,000 ₽ for each child.

Important:

• The educational institution must have license (for children - any form of education, for yourself - only full-time/correspondence).
• The deduction can be obtained for 3 previous years (for example, in 2026 - for 2021, 2022, 2023).
• If the employer paid for the training, no deduction is allowed.

🏥 Deduction for treatment (including expensive)

For standard treatment the limit is - 120 000 ₽, for expensive (by list of the Federal Tax Service) - without restrictions.

Required documents:

• 📄 Agreement with the clinic.
• 💊 Receipts for medications (if they are included in list of the Federal Tax Service).
• 🏥 Certificate of payment for medical services (form for tax deduction).

🚗 Selling a car or apartment

If you owned property:

• Less than 3 years (for apartments purchased after 2016) or less than 5 years (for apartments purchased before 2016) - you need to file a declaration and pay personal income tax of 13% on income.
• More than the minimum tenure — there is no need to submit a declaration (but if it was sold for less than 70% of the cadastral value, the Federal Tax Service may ask for clarification).

For cars, the minimum tenure is 3 years, if the cost is above 250,000 ₽. When selling for less than this amount, a declaration is not required.

💼 Income of freelancers and self-employed

If you work for Simplified taxation system (STS) or as a self-employed person, you do not need to submit 3-NDFL - use it instead declaration according to the simplified tax system or a receipt in the “My Tax” application.

But if you:

• Received income not as an individual entrepreneur (for example, from foreign customers).
• They made money from cryptocurrency, streaming, and selling copyrights.

- then you will have to declare your income and pay 13% personal income tax (for residents) or 30% (for non-residents).

6. Current personal income tax codes and rates in 2026

In 2026, the Federal Tax Service updated some income and deduction codes. Below are the key values ​​for filling out the declaration.

Category	Code	Description	Personal income tax rate
Income	2000	Salary	13%
	1520	Dividends	13%
	1530	Income from the sale of property	13% (for residents)
	2760	Winnings and prizes	35%
Deductions	311	Standard deduction for children	—
	320	Social deduction (treatment, training)	—
	312	Property deduction (purchase of housing)	—

For non-residents (residing in the Russian Federation for less than 183 days a year), the personal income tax rate for most income is - 30%. Exceptions:

• 💼 Income from the labor activities of highly qualified specialists - 13%.
• 🏢 Dividends - 15%.

If you received income in foreign currency, it must be converted into rubles according to Central Bank exchange rate on the date of receipt. Courses can be found on the Central Bank website or in the taxpayer’s Personal Account (section Background information).

7. Deadlines for checking the declaration and refunding money

After filing the return, the tax office conducts desk auditwhich lasts:

• 🕒 3 months - for deduction declarations.
• 🕒 2 months — for income declarations (if there are no errors).

If you applied for a deduction, after checking the Federal Tax Service will make a decision:

• ✅ Approved — the money will be credited to your account within 1 month from the date of the decision.
• ❌ Denied — a notification will be sent with a reason (for example, there are not enough documents).
• ⚠️ Need clarification — additional papers must be provided within 10 days.

⚠️ Attention: If you indicated the wrong account for the refund, the money will be stuck at the tax office. To correct this, write an application to change your details through your Personal Account or contact the inspectorate in person. The process may take up to 30 days.

You can track the status of your declaration:

• 📱 B Taxpayer's personal account (section My taxes → 3-NDFL).
• 📧 By email (if notifications are enabled).
• 📞 By calling the Federal Tax Service hotline: 8-800-222-22-22.

If the inspection takes longer than 3 months, write a complaint via feedback form on the Federal Tax Service website. In 90% of cases this speeds up the process.

8. Frequently asked questions about filling out 3-NDFL online

🔹 Is it possible to fill out 3-NDFL on paper and take it to the tax office?

Yes, but starting from 2022, the Federal Tax Service recommends filing your declaration electronically. If you still want to pass on paper:

1. Download the form 3-NDFL 2026 from the Federal Tax Service website.
2. Fill out in duplicate (by hand or on the computer).
3. Take it to the inspectorate at your place of residence or send it by mail (with a list of the contents).

The verification period for a paper declaration is up to 4 months.

🔹 What to do if you forgot the password for your taxpayer’s personal account?

You can restore access:

• Via Public services (if the account is verified).
• In any tax office (passport required).
• By calling the Federal Tax Service hotline (if you specified the number during registration).

The new password will be sent by email or SMS.

🔹 How to correct an error in a submitted declaration?

If you find an error before the deadline for submission (by April 30 for income), submit updated declaration:

1. In your Personal Account, select Submit an updated declaration.
2. Correct any errors and resubmit.

If the deadline has passed, write explanatory letter in free form and attach the correction. There will be no fines if the error did not result in an understatement of tax.

🔹 Is it possible to submit 3-NDFL through a bank (SberBank, Tinkoff)?

Yes, some banks offer this service to clients. For example, in SberBank Online:

1. Go to section Taxes and duties → Tax deductions.
2. Select the type of deduction and upload documents.
3. The bank itself will generate a declaration and send it to the Federal Tax Service.

The service is free, but is not available for all types of deductions (for example, the deduction for the purchase of housing is not supported).

🔹 How many times can you apply for deductions for the same training?

You can get a tuition deduction once for each year of payment. For example, if you paid tuition in 2021, 2022 and 2023, you can submit three returns (one for each year).

But there are limitations:

• Maximum deduction amount per year - 120 000 ₽ (including other social deductions).
• For teaching children the limit is - 50,000 ₽ per child.