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Fraud Detection — Confusion Matrix & Metrics Calculator

Compute accuracy, precision, recall, F1, specificity, MCC and more for fraud detection from TP/FP/FN/TN counts.

Accuracy (%)
Precision (%)
Recall (sensitivity) (%)
F1 score
Specificity (%)
Matthews corr. (MCC)

Fraud detection is extreme class imbalance (fraud is often <1% of transactions) where recall — catching fraud — is paramount but precision can't collapse or analysts drown in false alarms. This calculator highlights recall, precision and the cost-weighted trade-offs central to fraud teams.

Formula

precision = TP/(TP+FP) · recall = TP/(TP+FN) · F1 = 2PR/(P+R) · specificity = TN/(TN+FP) · MCC = (TP·TN−FP·FN)/√((TP+FP)(TP+FN)(TN+FP)(TN+FN))
References: Matthews (1975), Comparison of predicted and observed secondary structure (MCC); Powers (2011), Evaluation: From Precision, Recall and F-Measure to ROC, Informedness, Markedness & Correlation

Disclaimer: This tool is for general informational and estimation purposes only and is not professional financial, tax, accounting or legal advice. All figures are estimates — verify with a qualified professional before making decisions. Read the full disclaimer.

About Fraud Detection — Confusion Matrix & Metrics Calculator

Fraud detection is extreme class imbalance (fraud is often <1% of transactions) where recall — catching fraud — is paramount but precision can't collapse or analysts drown in false alarms. This calculator highlights recall, precision and the cost-weighted trade-offs central to fraud teams. Enter the four confusion-matrix counts and this calculator returns every standard metric — accuracy, precision, recall (sensitivity), F1, specificity and the Matthews correlation coefficient — recomputed live. MCC is highlighted because it is the most honest single number for imbalanced problems: it only scores high when the model does well across all four quadrants, unlike accuracy or F1 which can be gamed.

How to use Fraud Detection — Confusion Matrix & Metrics Calculator

  1. 1Enter your values into Fraud Detection — Confusion Matrix & Metrics Calculator — sensible, domain-typical defaults are pre-filled so you see a real result immediately.
  2. 2The result recomputes live using the formula shown on the page; there is no button to press.
  3. 3Adjust any input to compare scenarios, then read the worked example to see the substituted numbers.

Why use Fraud Detection — Confusion Matrix & Metrics Calculator?

  • Computes Fraud Detection instantly in your browser — no sign-up, no upload, no server round-trip.
  • 100% free and unlimited, with the exact formula shown: precision = TP/(TP+FP).
  • Runs entirely client-side, so every value you enter stays private on your device.
  • Live recompute as you type, with a worked example and authoritative references for trust.

Frequently asked questions

Why is accuracy useless for fraud detection?+

With fraud at 0.5% of transactions, predicting 'legitimate' for everything scores 99.5% accuracy and catches zero fraud. Teams instead track recall (fraud caught), precision (alert quality) and dollar-weighted metrics, since a missed $50K fraud differs wildly from a missed $5 one.

How do fraud teams balance precision and recall?+

Via the cost of each error: false negatives lose money directly, false positives cost analyst review time and customer friction (declined legit cards). Most teams set recall targets (catch X% of fraud value) then maximize precision within that, often using the F-beta score with β>1.

Why is MCC considered the most reliable single metric?+

MCC uses all four confusion-matrix cells and behaves like a correlation coefficient (−1 to +1): it is high only when predictions track reality across both classes. On imbalanced data where accuracy and even F1 can mislead, MCC stays informative — which is why it's increasingly the recommended summary statistic.

What's the difference between recall and specificity?+

Recall (sensitivity) is the fraction of actual fraudulent cases the model catches — TP/(TP+FN). Specificity is the fraction of actual legitimate cases it correctly clears — TN/(TN+FP). A model can have high recall and low specificity (flags everything) or vice versa; you need both to judge it.

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