Why Average DNA Results?
Different testing companies may report slightly different ancestry percentages for the same person because each uses distinct reference datasets and algorithms. By averaging results from multiple companies, you can form a broader picture of your heritage. This calculator lets you enter up to two sets of percentages for three regions. It returns the combined values and computes a diversity score using a common ecological formula.
Formula for Combined Percentages
The average percentage for each region is calculated by summing the two values and dividing by two. In MathML:
where and are the percentages from tests 1 and 2 for region i. Next, we calculate a diversity score inspired by Simpsonās Diversity Index:
The diversity score ranges from 0 (all ancestry from a single region) to close to 1 (even mix across regions). It provides a fun way to visualize how varied your genetic background might be.
Example Table
| Region | Test 1 | Test 2 | Average |
|---|---|---|---|
| Region A | 40% | 45% | 42.5% |
| Region B | 35% | 30% | 32.5% |
| Region C | 25% | 25% | 25% |
With these averages, the diversity score would be calculated as etc., resulting in roughly 0.67. The closer the score is to 1, the more evenly distributed your ancestry.
Interpreting Your Results
Remember that DNA tests provide estimates, not absolute truths. Each company uses proprietary reference populations, and results can change as databases grow. While the percentages are interesting, they canāt capture the entirety of cultural heritage. Family stories, traditions, and historical context add nuance beyond what genetics reveal.
If two tests disagree significantly, averaging them might soften extremes, but you should also read about each companyās methodology. Some specialize in certain regions or use more samples from one area than another. The diversity score simply quantifies how balanced your ancestry appears across the three categories you entered.
Limitations and Ethical Considerations
This tool is for educational and entertainment purposes. Genetic ancestry testing raises privacy concerns because it involves sensitive biological data. Before sharing your results online, consider the implications for you and your relatives. Data breaches or changes in company policy could expose information you intended to keep private.
Another caveat is that ancestry tests are less precise for people with ancestors from underrepresented regions. If few samples from your heritage are in a companyās database, the percentages may be more speculative. Therefore, always interpret results in context.
A Broader Perspective
Many genealogists combine DNA results with traditional record searchesābirth certificates, immigration documents, and oral histories. By pairing genetic evidence with paper trails, you can construct a richer family narrative. You might discover connections to historical events or migratory patterns. Studying how your ancestors moved across continents can foster a deeper appreciation for different cultures.
Even if you donāt uncover long-lost relatives, exploring ancestry can create a sense of belonging and curiosity about the past. Itās a reminder that each of us carries stories from countless generations. Whether you choose to frame your heritage in percentages, stories, or a blend of both, celebrate the diversity that makes you unique.
Worked Example
Suppose three testing companies return slightly different estimates for your background. Company A reports 40% RegionĀ A, 35% RegionĀ B, and 25% RegionĀ C. Company B suggests 45% RegionĀ A, 30% RegionĀ B, and 25% RegionĀ C. Plugging these numbers into the form yields averages of 42.5% for RegionĀ A, 32.5% for RegionĀ B, and 25% for RegionĀ C. Squaring and summing these decimals gives 0.425Ā² + 0.325Ā² + 0.25Ā² ā 0.332. Subtracting from 1 provides a diversity score of about 0.67, indicating a fairly balanced ancestry profile. You can rerun the calculation with different region groupings or additional tests to see how your score shifts.
Major DNA Testing Companies
| Company | Regions Reported | Notable Features |
|---|---|---|
| 23andMe | ~2,000 | Health reports, large database |
| AncestryDNA | ~1,800 | Family tree integration |
| MyHeritage | ~2,100 | Global user base, chromosome browser |
Each company updates its reference panels periodically, so percentages may change as databases grow. Some tools, like chromosome browsers, allow you to inspect which segments of your genome align with specific populations, revealing more nuance than headline percentages alone.
Extending Beyond Three Regions
The calculator focuses on three regions for simplicity, but you can adapt the averages manually for additional categories. For example, if you have data for five regions, average each pair separately and then compute the diversity score by summing the squares of all five averaged percentages. The formula generalizes to any number of regions:
Where n is the number of regions. The more evenly distributed your percentages, the closer the diversity score approaches one. Experimenting with additional data can highlight distant ancestries that make up only a sliver of your genome.
Limitations and Ethical Considerations
The calculator assumes that each test is equally reliable and that percentages represent recent ancestry. In reality, algorithms vary and may emphasize different time scales. Some companies weight genetic segments according to where reference samples live today, which can obscure historical migrations. If your parents are from mixed backgrounds, the inheritance pattern of DNA means you might not inherit every ancestral component equally. Furthermore, small percentage differences may fall within statistical noise, so avoid overinterpreting minor discrepancies.
Ethically, sharing genetic data requires caution. Relatives who never consented to testing may still be identifiable through your results. Lawāenforcement requests, data breaches, or policy changes could expose information years after you submit a saliva sample. Before uploading raw data to thirdāparty sites that promise deeper analysis, review their privacy policies and security practices.
Related Calculators
Explore more genetics tools such as the DNA Sequencing Coverage Calculator for lab planning or the DNA Codon Translation Calculator when studying genes in detail.