Prepayment of capital gains tax 

Intended audience: Individuals subject to Washington’s capital gains tax.

Starting with tax year 2026, you may prepay your capital gains tax up to six months before the filing and payment due date.

Payments are typically due on April 15th, unless this falls on a weekend or holiday. For tax year 2026, you may submit your payment beginning Oct. 15, 2026, for returns due on April 15th, 2027.

You may not deduct prepayment amounts when calculating federal net long-term capital gain on your Washington capital gains return (RCW 82.87.020(3)).

How do I make a prepayment?

To make a prepayment, you must first register for a Capital Gains tax account. For instructions, see Create a capital gains account section of our Capital Gains - My DOR help webpage.

After you create a capital gains account, we encourage you to gain access to your account using a letter ID.

Pay with access to your capital gains account

1. On dor.wa.gov click the Log in button.
2. Enter your SAW User ID and Password and click Log in to My DOR. If asked, complete the Multi-Factor Authentication challenge to verify your identity.
3. On the My DOR Services page, click Get Started. If you have access to more than one individual, click the name of the individual requiring a payment.
4. In the applicable account Balance panel, click the Make a Payment link.

For a complete list of instructions, see the Make a payment section on our My DOR help webpage.

Pay without access to your capital gains account

1. On dor.wa.gov click the Log in button.
2. Enter your SAW User ID and Password, then click Log in to My DOR. If asked, complete the Multi-Factor Authentication challenge to verify your identity.
3. On the My DOR Services page, in the Capital Gains section, click the Pay Without Filing link.
4. On the Instructions page, review the instructions, then click Next.

For a complete list of instructions, see our Capital Gains - My DOR help webpage.

Note: You will not be able to make a prepayment using tax preparation software.