How Credit Scores Are Calculated

What is credit score calculation?

Credit score calculation is the statistical scoring of your bureau file using a regression model trained on millions of historical borrower outcomes. FICO® 8 — the most widely used model — weights payment history 35%, amounts owed 30%, length of history 15%, credit mix 10%, and new credit 10%.

Why this matters

• Effort directed at low-weight categories produces low-impact results.
• Utilization (30%) is the only major factor you can move in 30 days.
• Payment history (35%) can wipe out years of optimization with one 30-day late.

How it works

• ›Payment history (35%): every monthly tradeline status — current, 30/60/90/120 days late, collection, charge-off.
• ›Amounts owed (30%): aggregate and per-card utilization, installment balance ratios, total revolving exposure.
• ›Length of credit history (15%): age of oldest account, average age, age of newest.
• ›Credit mix (10%): blend of revolving (cards) and installment (loans) tradelines.
• ›New credit (10%): hard inquiries and recently opened accounts in the last 12 months.

Examples in practice

Step-by-step process

1. 1

   Map current score to factor analysis

   Most FICO® dashboards show 'top factors affecting your score' — start there.

2. 2

   Prioritize by weight, not feeling

   Payment + utilization = 65% of your score; chase those first.

3. 3

   Stage interventions by speed

   Utilization moves in 30 days, disputes in 30–45, new tradelines in 60–90, time-based factors in years.

Action checklist

• Zero 30+ day lates in last 24 months
• Aggregate utilization under 10%
• At least one revolving account 36+ months old
• Three or more active tradelines
• No more than 2 hard inquiries in the last 6 months

Common mistakes to avoid

• Obsessing over credit mix while ignoring utilization
• Adding new cards to 'lower utilization' — average age drops too
• Letting one card sit at 90% while others are at 0% (per-card utilization still hurts)

Frequently asked questions