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Updated 2026-03-07 UTC
R² Calculator — Coefficient of Determination — GetCalcMaster
Compute R² from SSE and SST: R² = 1 − SSE/SST. Understand what R² means (and what it doesn’t) in regression and prediction.
R² (coefficient of determination) measures the fraction of variance in Y explained by the model, relative to predicting the mean. It’s a fit metric—not a causal metric.
Important: Educational. Prefer out-of-sample metrics (CV, test set) for predictive performance.
What this calculator is
The Statistics Calculator is an interactive tool inside GetCalcMaster. It’s designed to help you explore scenarios, understand formulas, and document assumptions.
Key features
- Simple computation from SSE and SST
- Clarifies interpretation and limitations
- Pairs with adjusted R² for model comparison
Formula
R² = 1 - SSE / SSTQuick examples
If SSE=40 and SST=100 → R²=1−0.4=0.6 (60% of variance explained in-sample).If SSE=SST → R²=0 (no improvement over predicting the mean).
How to use it (quick steps)
- Compute SST = Σ(yi − ȳ)² (total variance around the mean).
- Compute SSE = Σ(yi − ŷi)² (model residual sum of squares).
- Compute R² = 1 − SSE/SST.
- Interpret as fraction of variance explained (in-sample).
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FAQ
Is this calculator official?
No. GetCalcMaster provides educational estimates and learning tools. Always verify against official definitions, documents, or professional advice.
Do you store my inputs on the server?
No. Calculations run locally in your browser. Optional remember/restore features (if enabled) use local browser storage.
Tip: For reproducible work, save your inputs and reasoning in Notebook.