Understand the relationship
The reasoning behind the result
The pool is a weighted concentration
Cpool = Σ(CᵢVᵢ)/(ΣVᵢ + Vdiluent)
Each sample contributes concentration times volume of material. Those amounts add. Dividing their total by the combined final volume gives the pooled concentration. An unweighted mean of stock concentrations is correct only in the special case of equal stock volumes with no added diluent.
All stocks must describe the same measured material and compatible concentration units. A numerical total does not establish chemical compatibility, sample identity or suitability for a downstream assay.
Equal volume and equal material are different designs
For equal mass m: Vᵢ = m/Cᵢ
Equal-volume pooling gives more material weight to concentrated stocks. Equal-mass pooling compensates by taking a smaller volume from a more concentrated stock. The tool reports individual material shares so the difference remains visible.
A required volume above the entered available amount is rejected. Increasing the concentration by arithmetic or silently reducing a contribution would change the intended pool and is not done.
Diluent changes concentration without changing contribution shares
Material-free diluent increases final volume but adds none of the measured material. The pooled concentration decreases while each contributing sample retains the same share of the total material.
The model assumes additive volumes and no preparation loss. It does not estimate detection sensitivity, representativeness or biological outcomes after pooling.
Follow the numbers
Why an ordinary average is wrong
- Sample A contributes 20 ng/µL × 10 µL = 200 ng.
- Sample B contributes 50 ng/µL × 20 µL = 1,000 ng.
- The pool contains 1,200 ng in 30 µL: 40 ng/µL. Sample A supplies 1/6 of its material; B supplies 5/6.
The simple average of 20 and 50 would be 35 ng/µL, which does not describe this unequal-volume pool.
Quick guide
How to use this calculator
- Choose entered volume or equal material mass.
- Enter each stock concentration and volume available.
- Enter any additional diluent.
- Check the required volume and material share of every sample before using the pooled totals.
Calculation method
Calculation and interpretation
Build a pool from an explicit contribution ledger and reconcile total volume with total material.
Materialᵢ = concentrationᵢ × volumeᵢ; pooled concentration = Σmaterialᵢ/(Σvolumeᵢ + diluent)
Worked example
Why an ordinary average is wrong
The simple average of 20 and 50 would be 35 ng/µL, which does not describe this unequal-volume pool.
Materialᵢ = concentrationᵢ × volumeᵢ; pooled concentration = Σmaterialᵢ/(Σvolumeᵢ + diluent)
Supported inputs
Precision and limits
An entered laboratory plan
This tool reconciles the measurements and choices you enter. It does not select a biological protocol, certify a preparation, assess sample suitability or establish an equipment operating limit.
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