The free AHP calculator.
List your criteria, set the pairwise comparisons on the Saaty 1 to 9 scale, and get the priority weights and the consistency ratio instantly. Bookmark it for quick calculations. Same math as the SpiceLogic AHP Software.
1 Your criteria
3 Priority weights
4 Behind the numbers
See the full calculation, step by step
Weights use the Approximate Eigen Vector method. The consistency ratio uses Saaty's Random Index. Your inputs stay in this browser.
From pairwise comparisons to a defensible ranking.
The Analytic Hierarchy Process turns subjective judgments into objective weights, then checks whether those judgments are logically consistent. This calculator does the criteria step.
- Compare in pairs. For every pair of criteria you answer one question: which matters more, and by how much, on the Saaty 1 to 9 scale (1 equal, 3 moderate, 5 strong, 7 very strong, 9 extreme).
- Derive the weights. The calculator builds the pairwise comparison matrix, normalizes each column so it sums to 1, and averages each row. The result is the relative priority weight of every criterion.
- Check consistency. It then computes the principal eigenvalue, the Consistency Index CI = (lambda max - n) / (n - 1), and the Consistency Ratio CR = CI / Random Index. A CR of 0.10 or less means your judgments hold together; above 0.10, you should revise them.
This calculator covers the criteria step. For the full method, including ranking your actual alternatives and running sensitivity analysis, see the AHP Software documentation.
When the decision is bigger than a quick calculation.
This page weighs criteria. The full AHP Software builds the whole model, ranks your actual options, and produces a report you can defend.
- Rank your real alternatives, not just the criteria
- Unlimited criteria and sub-criteria, guided by a wizard
- Sensitivity analysis with live, interactive charts
- Transitivity Rule cuts the number of comparisons and forces consistency
- Group decisions: aggregate several decision-makers (AIJ or AIP)
- Export thesis-ready reports to PDF or Excel
- Perpetual license, fully offline, no cloud dependency
- Free live onboarding training
AHP and the consistency ratio, explained.
What is the Analytic Hierarchy Process (AHP)?
AHP is a structured method for making complex, multi-criteria decisions. You break a decision into a hierarchy of a goal, criteria, and alternatives, make simple pairwise comparisons between them, and the math turns those judgments into a defensible ranking with a built-in consistency check. It was developed by Thomas L. Saaty and is grounded in mathematics and psychology.
How does this AHP calculator derive the priority weights?
For the pairwise comparison matrix the calculator normalizes each column so it sums to 1, then takes the arithmetic mean of each row to get the relative weight of every criterion. This is the Approximate Eigen Vector method, the standard and recommended approach. The SpiceLogic AHP Software additionally lets you switch to the Largest Eigenvector, Geometric Mean, or Fuzzy Geometric Mean method.
What is the Consistency Ratio and how is it calculated?
The Consistency Ratio (CR) measures how far your pairwise judgments deviate from perfect consistency. It is computed as CR = Consistency Index / Random Index, where the Consistency Index is CI = (lambda max - n) / (n - 1), lambda max is the principal eigenvalue of your comparison matrix, and n is the number of items compared. The Random Index is Saaty's expected consistency for a randomly filled matrix of the same size.
What Consistency Ratio is acceptable?
According to Thomas L. Saaty, the Consistency Ratio should be less than or equal to 0.10. If your CR is above 0.10 your judgments are too inconsistent and should be revised. The SpiceLogic AHP Software flags any Consistency Ratio over 0.10 in red so you know which comparisons to revisit.
Can I reduce the number of pairwise comparisons I have to make?
Yes. Without any shortcut, n items require n times (n - 1) divided by 2 comparisons. If you enforce the Transitivity Rule, the comparisons drop to just (n - 1) because the remaining preferences are inferred logically, and your judgments become perfectly consistent so the Consistency Ratio becomes 0. The SpiceLogic AHP Software lets you turn this rule on to save time.