How does my credit score work and what affects it most?

Your FICO credit score (300–850) is calculated from five factors: Payment History (35%) — the biggest factor; a single 30-day late payment can drop your score 50–100 points. Credit Utilization (30%) — how much of your available revolving credit you are using; keep each card and your total below 30%, ideally below 10%. Length of Credit History (15%) — older accounts help, so avoid closing your oldest cards. Credit Mix (10%) — having both revolving (cards) and installment (auto, mortgage, student loans) credit helps. New Inquiries (10%) — each hard inquiry from a new credit application can lower your score by 5–10 points temporarily. Use the Credit Score Simulator at wealthserene.com/tools/credit-score-simulator to model how different actions would affect your score.