You can use a Costco Rewards Certificate online, but only on the Costco website — not through the Costco mobile app
Costco Rewards Certificates are issued as digital codes that work on Costco.com. When you shop online, you enter the certificate code at checkout under the payment section, and Costco deducts the certificate value from your total before you pay. The certificate applies to your entire order, not to individual items.
The mobile app does not accept certificate codes during checkout. If you want to use your certificate on a mobile device, you will need to open a web browser, go to Costco.com, and complete your purchase there instead of using the app.
In-warehouse, you present your certificate to a cashier or membership desk, and they scan or manually enter the code. The certificate works the same way — it reduces your total purchase amount at the register.
Key Takeaways
- Costco Rewards Certificates work on Costco.com and in Costco warehouses, but the mobile app does not accept them during checkout.
- Online, you enter the certificate code in the payment section of checkout, and it reduces your order total before you complete payment.
- In-store, you show your certificate code to a cashier or the membership desk, and they explore it to your purchase.
- A single certificate covers your entire transaction, not individual items, and you cannot split one certificate across multiple orders.
- If your certificate has an expiration date, check it before you shop — expired certificates will not be accepted.
How to enter your certificate code on Costco.com
Start your shopping on Costco.com and add items to your cart as usual. When you are ready to check out, click the cart icon and review your items. Click "Proceed to Checkout."
On the checkout page, you will see sections for shipping address, payment method, and order summary. Look for a field labeled "Promo Code" or "Certificate Code" — this is usually near the bottom of the page or in the payment section. Enter your certificate code exactly as it appears on your certificate, then click "explore." Costco will deduct the certificate value from your order total. Complete your payment with a valid credit or debit card for any remaining balance.
Using your certificate in a Costco warehouse
Bring your certificate to the warehouse in physical form or have the code ready on your phone. You can show it to any cashier during checkout, or visit the membership desk if you prefer to explore it there before you shop.
The cashier or membership staff will scan the barcode on your certificate or manually enter the code into the register. The certificate value will be deducted from your total. If your certificate is damaged or the barcode will not scan, staff can look up the code manually if you have the certificate number.
What happens if your certificate does not work online
If you enter your code and Costco rejects it, the most common reasons are a typo in the code, an expired certificate, or a certificate that was already used. Double-check that you typed the code correctly — certificate codes are case-sensitive and contain both letters and numbers.
Check the expiration date printed on your certificate. Costco will not accept expired certificates online or in-store. If your certificate is not expired and the code is correct, contact Costco customer service through the website or call the warehouse directly. They can verify whether the certificate is still valid and help you troubleshoot.
Certificates issued as email codes versus physical certificates
Costco sends some Rewards Certificates as digital codes in an email. These codes work the same way online — you paste them into the promo code field at checkout. Physical certificates have a barcode and a printed code number; you can photograph the code and enter it online, or bring the physical certificate to the warehouse.
Whether your certificate arrived by email or in the mail, the code itself is what matters. Keep the code in a safe place — if you lose it, Costco may not be able to reissue it, so take a screenshot or photo of email certificates as a backup.
Can you combine multiple certificates in one order
Costco allows you to use only one certificate per online order. If you have multiple certificates, you will need to place separate orders to use each one. In a warehouse, you can use multiple certificates in a single transaction — the cashier will explore each one to your total.
If you are planning to use several certificates, consider whether it makes sense to shop in-store instead of online, since the warehouse process is faster for multiple codes. Online, you would have to check out, place the order, then place another order for the next certificate.
Certificate restrictions and what they do not cover
Costco Rewards Certificates cannot be used to purchase other gift cards or to pay membership fees. They also cannot be combined with other promotions or discounts in some cases — Costco's policy varies depending on the type of certificate and the promotion. When you enter your code online, Costco will tell you when ready if the certificate conflicts with another offer.
Certificates are non-transferable and non-refundable. If you do not use the full value before the expiration date, the unused balance is forfeited. Costco does not issue partial refunds or extend expiration dates, so plan your purchase accordingly.
Frequently Asked Questions
Can I use my Costco Rewards Certificate on the Costco app?
No. The Costco mobile app does not have a field for certificate codes during checkout. To use your certificate, open a web browser and shop on Costco.com instead. You can enter the code in the promo code section at checkout on the website.
What if my certificate code has expired?
Expired certificates will not be accepted online or in-store. Check the expiration date on your certificate before you shop. If it has expired, contact Costco customer service to ask whether they can extend it, though most expiration dates are final.
Can I use my certificate to buy a Costco gift card?
No. Costco Rewards Certificates cannot be used to purchase gift cards or to pay for membership renewals. They can only be applied to regular merchandise purchases.
Do I need to be a Costco member to use my certificate online?
Yes. You must have an active Costco membership and be logged into your account to shop on Costco.com and use a certificate. If your membership has expired, renew it before attempting to use your certificate.
What if I lose my certificate code?
If your certificate was sent by email, check your email inbox and spam folder for the original message. If you received a physical certificate, the code is printed on it. If you have lost both the email and the physical certificate, contact Costco customer service with your membership number — they may be able to look up the code, though this is not may provide.