You generally need to be at least 18 years old to open your own credit card account, even if you have a co‑signer, and true co‑signed credit cards are not very common with major issuers.

Basic age rules

  • Under 18:
    • You usually cannot be the primary cardholder because you cannot legally enter a binding credit contract in most cases.
* Typical options are:
  * Being added as an **authorized user** on a parent’s or adult’s card.
  * In some cases, the adult opens a **secured card** in their name and lets you use it under strict rules.
  • Ages 18–20:
    • Federal rules say you must either:
      1. Show your own independent income that can repay the debt, or
      2. Apply with a co‑signer/joint applicant who is willing to be fully liable for the balance.
* Some card issuers simply do **not allow co‑signers** at all, even for adults under 21, so you have to check each bank’s policy.
  • Age 21+:
    • You can usually apply on your own without a co‑signer as long as your credit and income meet the bank’s requirements.

Co‑signer vs authorized user

  • Co‑signer / joint applicant
    • The adult is equally responsible for all charges and missed payments.
    • Missed payments hurt both of your credit scores and the co‑signer can be pursued for collections.
* Many big issuers now prefer **joint accounts** or business guarantees rather than a classic co‑signer setup.
  • Authorized user
    • You get your own card but are not legally liable ; the primary cardholder is.
* The account may still show on your credit report and help you build history if the issuer reports authorized‑user activity.

Mini story: what this looks like at 17 vs 19

  • At 17 , Alex wants “their own” card.
    • The bank says Alex is too young to sign the contract, even with a co‑signer, so Alex’s mom adds them as an authorized user on her long‑standing card.
    • Payments are kept on time, and Alex starts building a thin but positive credit history as a rider on mom’s account.
  • At 19 , Alex now has a part‑time job.
    • Alex applies for a student card and lists part‑time income; the issuer reviews whether that income is enough.
    • If not, Alex’s mom applies with Alex as a joint applicant or co‑signed applicant at a local credit union that still allows co‑signers, making both of them fully responsible.

Important fine print

  • Exact rules can vary by:
    • Country and state law.
    • Bank or credit union policies.
    • Card type (student, secured, store card, etc.).
  • Even where co‑signers are allowed, issuers typically require the primary cardholder to be at least 18 , and many large banks have moved away from co‑signed consumer cards altogether.

Information gathered from public forums or data available on the internet and portrayed here.