This is a simplified educational model, not a real credit score

Real FICO® and VantageScore® scores use proprietary formulas that neither company publishes in full, and individual lenders can weigh factors differently on top of that. This tool builds a transparent, simplified estimate from the factor weights myFICO has publicly disclosed, so you can see roughly how each ingredient moves the number — it is not, and cannot be, an actual FICO or VantageScore calculation.

The five FICO factor weights (myFICO)

• Payment history — 35%: whether accounts are paid on time.
• Amounts owed (utilization) — 30%: balances relative to credit limits.
• Length of credit history — 15%: how long accounts have been open.
• New credit — 10%: recent hard inquiries and newly opened accounts.
• Credit mix — 10%: variety of account types.

Each factor is modeled on a 0–100 scale in code, then combined using these weights into a projected score between 300 and 850. Month-over-month movement is capped so the projection can't jump implausibly in a single month — real scores are widely reported (via myFICO and Experian) to move gradually, not in sudden leaps.

Assumptions behind the two paths

Minimum Effort assumes no missed payments and no new accounts or inquiries, but no proactive changes either — utilization stays exactly where it started, and any past late payments' negative weight fades only very slowly. Its slow improvement comes almost entirely from the length-of-history factor, since accounts age regardless of behavior.

Targeted Effort assumes autopay is turned on for a perfect on-time streak, utilization is paid down toward roughly 10%, no new hard inquiries are added, and — only for scenarios starting with one or zero accounts — one additional account is opened around month 12 to build credit mix (causing a small, temporary dip from the new inquiry before recovering).

About the milestone thresholds

• 580 — the published minimum for FHA loan eligibility with a 3.5% down payment.
• 620 — a widely published conventional-mortgage minimum used by most lenders.
• 650* — unlike mortgage or auto-loan minimums, there's no official published credit-score requirement for renting — each landlord or property management company sets their own bar, and many weigh income, rental history, and references alongside (or instead of) credit score. The mid-600s is a commonly cited informal benchmark, but this milestone is a rough estimate, not a guarantee of approval.
• 670 — myFICO and Experian both publish this as the start of the "Good" tier, typically qualifying for many loans and cards at decent rates.
• 740 — myFICO and Experian both publish this as the start of the "Very Good" tier, typically eligible for the best advertised rates.

Constants we chose (worth sanity-checking)

Where FICO publishes a factor weight but not the exact shape of how fast each factor should move, we picked reasonable curves and documented them directly in the code's comments — things like how many months it takes utilization or payment history to reach their target under Targeted Effort, how slowly length-of-history climbs, and the maximum points a projected score can move in one month. These are our estimates for a plausible shape, not published constants.

What this calculator doesn't account for

• Individual lender criteria — different lenders and even different scoring model versions weigh factors differently.
• Account types — credit mix here is approximated from account count, not the actual variety of installment vs. revolving accounts.
• Collections, bankruptcies, or other derogatory marks — not modeled.
• This is an educational estimate, not financial advice — consult a financial professional for guidance tailored to your situation.