Kinship Coefficient Calculator (Relationship r & Coancestry φ)
Compute Wright's r = Σ (1/2)^(n1+n2)(1+F_A) and kinship φ = r/2 for two individuals, with reference values (full sib 0.5, half sib 0.25, first cousins 0.125) and relationship-degree classification. Child F = parental φ. Derived from Wright 1922, Falconer & Mackay, Hartl & Clark 2007, Jacquard 1970. Educational use only.
Execution
Run this tool
Fill in the form, run the tool, and review the result in one place.
Samples
Examples that match this tool
Related
Continue with connected tools and hubs
Result
Ready for a run
Run the tool to preview files, text, structured data, or streamed output here.
Tool usage guide
Learn when to use this tool, what it supports, and how real users apply it.
Key facts
Category
Education
Input types
select, number, textarea
Output type
json
Sample coverage
4
API ready
Yes
Overview
The Kinship Coefficient Calculator computes Wright’s coefficient of relationship r and kinship coefficient φ for two individuals using shared-ancestor paths. It can also estimate a child’s inbreeding coefficient F as the parental φ and classify the relationship by degree. Educational use only.
When to use
Estimate genetic relatedness from the generations separating two individuals from a common ancestor.
Sum contributions from multiple common-ancestor paths in a pedigree.
Calculate kinship φ and the expected child inbreeding coefficient F for an educational pedigree analysis.
How it works
1Choose Single common ancestor path or Multiple paths (sum over ancestors).
2For a single path, enter n1, n2, and the common ancestor’s inbreeding coefficient F_A.
3For multiple paths, enter one n1, n2, F_A line per path; F_A may be omitted and defaults to 0.
4The calculator applies r = Σ (1/2)^(n1+n2)(1+F_A), returns φ = r/2, estimates child F = φ, and provides a relationship-degree classification.
Use cases
Teaching Wright’s path method, kinship, and coancestry in genetics courses.
Checking textbook relationship values for full siblings, half siblings, and first cousins.
Exploring how multiple pedigree paths affect relatedness and offspring inbreeding.
Examples
1. Calculate relatedness between full siblings
Genetics student
Background
A student wants to verify the classic relationship value for two full siblings who share both parents.
Problem
A single shared ancestor path would omit the second parent and underestimate the relationship.
How to use
Select Multiple paths and enter two lines, one for each parent: 1, 1, 0.