Card Number, Expiry, CVV: The Parts of a Card Explained

Every online checkout asks for the same few card details. Most people enter them without thinking, but when a payment fails, knowing what each field does helps you find the problem quickly. This is especially useful with virtual cards, where you copy details from a screen rather than reading them off plastic.

This guide explains each part of a card and how to enter it. It is general information about how card payments usually work.

The card number

The card number — sometimes called the PAN (primary account number) — identifies the card. Most cards have 16 digits; some brands use 15. The number has a structure:

• The first digits identify the card network and issuer. Checkout forms use them to show the right logo.
• The middle digits identify the individual card.
• The last digit is a check digit that lets forms catch most typing errors instantly.

Entering it: copy it exactly, without spaces if the form rejects them. If a form says the number is invalid, a digit has usually been missed or swapped.

The expiry date

The expiry date shows the month and year until which the card is valid, usually written as MM/YY. A card generally works until the end of the expiry month.

Entering it: match the format the form asks for — some use two dropdowns, others a single MM/YY field. A wrong expiry date is one of the most common reasons for a decline.

The CVV

The CVV (also called CVC, CVV2 or security code) is a three- or four-digit code. It proves that the person paying has the full card details, not just the number. Merchants are not allowed to store it after a payment, which is why some sites ask for it again even when they have saved your card.

Entering it: type the code exactly. Never share it with anyone by message or phone; legitimate merchants only ask for it in a secure checkout form.

The cardholder name

The cardholder name is the name associated with the card. Some merchants check it; many do not.

Entering it: use the name exactly as it appears on the card details. For virtual cards, copy the name from your card details rather than typing your own if they differ.

The billing address

The billing address is the address associated with the card. Some merchants use it for fraud checks through an address verification system, which compares the numbers in the street address and postal code with what the issuer has on record.

Entering it: if your card provider gives you a billing address, use it exactly — including the postal code — at checkouts that ask for one. Our article on the billing address at checkout explains when this matters.

Other fields you may see

• Phone number or email: used by the merchant for receipts and contact; usually not checked against the card.
• Country: should match the billing address country where a billing address is required.
• 3-D Secure or verification step: some payments trigger an extra verification step from the card issuer. How it works depends on the issuer and the card.

Why a checkout might reject correct details

Even with correct details, a payment can be declined because of:

• insufficient balance, including fees, holds or currency conversion,
• the merchant not accepting prepaid or virtual cards,
• address mismatches at merchants that check them,
• the card being frozen or expired.

Our guide on why card payments get declined goes through these in detail.

Keeping card details safe

• Enter card details only on secure checkouts you reached yourself.
• Never send card details by email or chat.
• Avoid saving cards at sites you do not trust.
• Reveal virtual card details only when you need them, and hide them afterwards.
• If you think details have been exposed, contact your card provider.

Copying details from a screen

With virtual cards, details are usually copied from an app or account page. Some tips:

• Use copy buttons where available to avoid typos.
• Paste into the checkout field and check the result — especially that no spaces or characters were added.
• Do not keep card details in your clipboard longer than needed, and avoid pasting them into notes or messages.

Common entry mistakes

Most failed payments caused by card details come from a short list of slips:

• swapping two digits in the card number,
• choosing the wrong year in an expiry dropdown,
• entering the expiry in the wrong order, such as year before month,
• leaving a space at the end of a pasted name or code,
• typing your own address instead of the card's billing address where one is provided.

Before pressing pay, take a moment to read each field back against the card details. It takes seconds and avoids a decline that could trigger extra checks at the merchant.

Saved cards and autofill

Browsers and password managers can save card details and fill them in automatically. That is convenient but means the details are stored on your device or in a cloud account. For prepaid cards used for a single purpose, many people prefer not to save them at all, and to copy the details from the provider's account only when needed. If you do save a card, protect the browser or password manager with strong security.

Card details on BuyCryptoCard

In your BuyCryptoCard account, "My Cards" shows each card's masked number, expiry, cardholder name and, where provided, a billing address, each with a copy button. The full number and CVV are revealed only after you enter a fresh code from your authenticator app, and they hide again after one minute. The how it works page explains how cards appear in your account.

Frequently asked questions

Why does the checkout ask for my CVV again?

Merchants may not store the CVV, so they ask for it with each payment that requires it.

What if my name differs from the cardholder name?

Use the cardholder name shown on the card details.

Is the expiry date the last day the card works?

Cards generally work until the end of the expiry month.

Summary

A card payment uses the card number, expiry date, CVV, cardholder name and sometimes a billing address. Each has a purpose, and errors in any of them can cause declines. Copy virtual card details carefully, enter them only in secure checkouts and keep them private.