What is the difference between a co-signer and a co-borrower on a personal loan?

Co-signer details: A co-signer applies alongside the primary borrower and their credit score and income help the primary borrower qualify or get a better rate. However, the co-signer is a guarantor: they only make payments if the primary borrower defaults. In most personal loan structures, the co-signer does not receive the loan proceeds and is not expected to manage the account. The loan appears on the co-signer's credit report. If the primary borrower misses payments, the co-signer's credit is damaged. If the primary defaults entirely, the lender pursues the co-signer for the full remaining balance.

Co-borrower details: A co-borrower (joint applicant) is equally responsible for repayment from day one. Both applicants have equal access to account information and equal legal obligation. The loan appears on both borrowers' credit reports. This structure is used for shared expenses (a couple buying furniture together, siblings splitting a medical bill). Co-borrowers share both the benefit (both credit profiles are strengthened by on-time payments) and the risk (both are pursued in default).

Lender offerings: Most major online personal loan lenders offer joint (co-borrower) applications: LendingClub, Upgrade, LightStream, SoFi, Marcus. Co-signer programs (without full co-borrower status) are less common - Upstart and some credit unions offer this structure.

Choosing between the two: If you need help qualifying due to your credit, and the lender of choice offers co-signer (not just co-borrower): a co-signer protects your helper if the lender pursues them for full repayment. If you are splitting an expense with another person who will benefit: a co-borrower arrangement reflects the shared obligation accurately.