A credit score sometimes drops after paying off a large credit card balance because of how FICO weighs different account states. The most common reasons are: closing the account after payoff (loss of available credit), losing the only active installment loan if you paid off a personal loan, or a temporary scoring quirk where the algorithm prefers to see active utilization above 0% on revolving accounts. The drop is almost always temporary and minor.
The closed-account effect. If you paid off the card and the issuer closed it (for inactivity, hardship-program rules, or by your request), your total available credit just dropped. If you had $20,000 in available credit across all cards and the paid-off card was $10,000 of that, your remaining utilization on other cards just doubled in percentage terms. A score drop of 20-50 points is typical.
The 0% utilization quirk. Counter-intuitively, FICO sometimes scores 1%-3% utilization slightly higher than 0% utilization. This is because 0% utilization across all accounts can suggest the consumer is not actively using credit, which the model treats as marginally less informative than light, paid-in-full activity. The effect is small (3-10 points) but real.
Loss of installment-loan diversity. If you paid off a personal loan or auto loan and had no other installment loans, your credit mix loses a category. FICO considers credit mix (revolving vs. installment vs. mortgage) about 10% of the score. Losing your only installment loan can drop the score 10-20 points until you have another installment account.
Lost positive trade line over time. Closed accounts in good standing remain on your credit report for 10 years, contributing to length of credit history. After 10 years, the closed account falls off, and your average age of accounts can drop sharply if it was an old account. This delayed effect is why people sometimes see a score drop years after closing a card.
Statement timing. Credit card issuers report your balance to the bureaus on a specific date each month, usually your statement closing date. If your big payoff happened after the closing date, the bureaus still see the high balance for one more reporting cycle. Wait 30-60 days for the next reporting cycle to see the score recover.
How to recover. Keep using one or two cards lightly (a few small charges per month, paid in full) so the bureaus see active responsible use. Do not close paid-off cards unless they have an annual fee or you cannot trust yourself to keep them at zero. If you closed a card unintentionally, ask the issuer to reopen it; some will, some will not.
The bigger picture. A 20-point score drop after a $15,000 payoff is a reasonable price for $15,000 less in debt and the freedom from interest. The score recovers within 3-6 months in most cases. Do not let a minor temporary score change discourage you from continuing to pay off debt.