Resuspension Calculator

When a dried or lyophilized compound arrives in a vial, the Resuspension Calculator tells you exactly how much solvent to add to reach your target concentration. Enter the Mass in Vial and its unit (nmol, µmol, mg, etc.), then set your Desired Concentration and unit to get the Volume of Solvent to Add. Secondary outputs include the Final Stock Concentration and Total Final Volume — add a Molecular Weight if you're converting between mass-based and molar units.

g/mol

Required for mass-based calculations

Results

Volume of Solvent to Add

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Final Stock Concentration

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Total Final Volume

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Frequently Asked Questions

What is the difference between resuspension and dilution?

Resuspension involves dissolving dried or lyophilized material (like oligos) in a solvent to create a stock solution. Dilution involves taking an existing solution and adding more solvent to reduce its concentration.

What solvent should I use for oligo resuspension?

TE Buffer (10mM TrisHCl / 1mM EDTA) at pH 8.0 is recommended for most oligos. DNase-free water can also be used, but TE buffer provides better stability and prevents degradation.

How do I convert between different concentration units?

The calculator handles unit conversions automatically. For manual conversion: 1 μM = 1000 nM = 1,000,000 pM. Mass-based units require molecular weight for conversion to molarity units.

Why is molecular weight needed for some calculations?

When converting between mass-based units (mg, μg, ng) and molarity units (μM, nM, pM), molecular weight is required. The relationship is: Molarity = (mass in grams) / (molecular weight × volume in liters).

What if I don't know the molecular weight of my oligo?

Most oligo suppliers provide molecular weight on the product sheet. For estimation, single-stranded DNA oligos are approximately 330 g/mol per nucleotide, and RNA oligos are about 340 g/mol per nucleotide.

Can this calculator be used for proteins and other biomolecules?

Yes, the calculator works for any dried or lyophilized biomolecule where you know the mass and desired final concentration. Just ensure you use the appropriate molecular weight and solvent.

How should I store resuspended oligos?

Store resuspended oligos at -20°C for long-term storage or 4°C for short-term use. Avoid repeated freeze-thaw cycles by making aliquots. Most oligos are stable for months when properly stored.

What concentration should I aim for in my stock solution?

Common stock concentrations are 100 μM for most applications, though this varies by experiment. Higher concentrations (up to 1 mM) save storage space but may have solubility issues with some sequences.