Glossary

Principal

The original amount borrowed or invested, before any interest is added.

If you borrow 3,000, the principal is 3,000. Everything charged on top is interest.

The distinction matters most when repaying, because a payment is split between the two. Early in a loan most of each payment covers interest and only a little reduces the principal — which is why the balance seems to barely move at first, and why progress accelerates later once more of each payment reaches the principal.

It is also why paying extra matters more than it appears. An extra payment goes entirely against the principal, which reduces every future interest charge, not just this month’s.

When someone talks about “paying down the balance”, the useful question is how much of that is actually reaching the principal.

Words on this page

• Interest — The price of using someone else's money — paid by borrowers, earned by lenders.

Related terms

• Compound interest
• Amortisation
• Minimum payment

Covered properly in Learn.

Written by Edmund Warde. Last updated 30 July 2026.
Education, not financial advice — what that means.