COLONY HEALTH · FREE CALCULATOR
Enter the mites counted and number of adult bees sampled to calculate mites per 100 bees. Compare the result with a benchmark you choose without turning the calculator into a treatment prescription.
Calculator + methodology reviewed September 11, 2026.
COLONY HEALTH
Enter the number of mites counted and the number of adult bees sampled. Get mites per 100 bees, infestation percentage, and a comparison to a benchmark you choose.
The benchmark is a comparison aid, not a treatment instruction. Local action thresholds can vary by season, colony phase, and region.
Mite load
2.00 mites per 100 bees
A half-cup alcohol wash is commonly treated as roughly 300 bees. Confirm management decisions with current local extension guidance and the label for any product you use.
COLONY HEALTH MATH
A raw mite count only makes sense with sample size. Six mites from 300 bees is different from six mites from 100. This tool normalizes any sample to mites per 100 adult bees, numerically the same as the sampled-adult infestation percentage.
The comparison benchmark is editable because thresholds vary by season, colony phase, region, and guidance.
The Honey Bee Health Coalition describes proactive alcohol-wash or powdered-sugar sampling with roughly 300 adult bees. Custom sample sizes still work with the same formula.
The percentage is arithmetic. What to do next is an integrated-pest-management decision. The Honey Bee Health Coalition notes that thresholds are guidelines rather than absolutes and can vary with time of year, environment, colony strength, and management. Use current local guidance and the current label for any registered control product.
2.0 mites per 100 bees, or a 2.0% sampled-adult rate.
No. It reports the rate and compares it with the benchmark you select.
Yes. Any positive sample-size estimate can be normalized to mites per 100 bees.
Honey Bee Health Coalition — Varroa Management · Penn State Extension — Varroa IPM. Last reviewed September 11, 2026.