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Neb Gibson Assembly Calculator

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In the world of molecular biology, piecing together DNA fragments accurately is akin to completing a complex puzzle. The NEB Gibson Assembly Calculator is a digital tool designed to simplify this process. Developed by New England Biolabs (NEB), this calculator aids scientists in performing the Gibson Assembly method — a technique named after Dr. Daniel Gibson. This innovative method allows for the seamless joining of multiple DNA fragments without the need for restriction enzymes, revolutionizing how genetic research and engineering are conducted.

The Purpose and Functionality of the Calculator

The Gibson Assembly method is celebrated for its precision and efficiency in DNA assembly. However, achieving optimal results requires careful calculation of the amounts of DNA fragments to be used. This is where the NEB Gibson Assembly Calculator becomes invaluable. It assists researchers in determining the ideal quantities of vector backbones and inserts, based on their lengths and concentrations, to ensure a successful assembly process.

General Formula and Inputs:

To perform these calculations, the calculator uses several key inputs:

  • Vector Backbone Length
  • (in base pairs)
  • Insert(s) Length(s)
  • (in base pairs for each insert)
  • Concentration of Vector Backbone
  • (ng/µl)
  • Concentration of Insert(s)
  • (ng/µl for each insert)
  • Desired Molar Ratio of Vector to Insert(s)
  • (usually 1:2 or 1:3)

The calculations hinge on a simple yet effective formula that considers the molecular weight of DNA (660 Da/bp) to determine the molar amount of DNA in a sample. This approach allows researchers to calculate the volumes of vector and insert required for equimolar assembly in the reaction mixture.


The NEB Gibson Assembly Calculator uses a formula to figure out how much of each DNA piece you need to mix together. Let’s break it down into simple words:

  1. Starting Point: You have pieces of DNA you want to join together. Each piece has a length (measured in base pairs) and a concentration (how much DNA there is in a certain amount of liquid, measured in ng/µl).
  2. What We Need to Know:
    • Length of DNA Pieces: How long each DNA piece is. Longer pieces have more “weight.”
    • Concentration of DNA Pieces: How concentrated (or how thick) your DNA solution is.
    • The Mix Ratio: How much of each piece you want to mix. Usually, you mix them in a certain ratio to make sure they join together nicely.
  3. The Math Part: The calculator does some math to balance everything out. It uses a special number (660) because that’s roughly how much a single base pair of DNA “weighs” in a very tiny unit (Daltons). So, it calculates the “molar amount” of each DNA piece, which is a fancy way of saying it figures out how many molecules of DNA you have based on its length and concentration.
  4. Formula in Simple Words: For each DNA piece, the calculator figures out its “weight” in the mix. It uses the length, concentration, and the special number (660) to find out how much of it you need to get the mix just right. Then, it tells you how much volume (like how many microliters) of each DNA solution you should use based on how thick it is and how you want to mix them.

Step-by-Step Example

Let’s demystify the process with an example. Imagine you’re working with a vector that is 4000 base pairs long at a concentration of 50 ng/µl, and an insert that is 1000 base pairs long at 100 ng/µl. You aim for a 1:3 molar ratio of vector to insert. Here’s a simplified breakdown:

  1. Calculate the molar amount of the vector and insert.
  2. Adjust the amounts based on the desired molar ratio.
  3. Determine the volume of each component needed, factoring in their concentrations.

Relevant Information Table

InputExample ValueDescription
Vector Length (bp)4000Length of the vector DNA in base pairs
Insert Length (bp)1000Length of the insert DNA in base pairs
Vector Concentration (ng/µl)50Concentration of the vector solution
Insert Concentration (ng/µl)100Concentration of the insert solution
Desired Molar Ratio (Vector:Insert)1:3Ratio of vector to insert molecules


The NEB Gibson Assembly Calculator is more than just a tool; it’s a bridge to groundbreaking discoveries in genetics. By providing a straightforward way to calculate the optimal ratios and amounts of DNA fragments for assembly, it streamlines the Gibson Assembly process. This not only saves time but also increases the accuracy and efficiency of genetic assembly projects. Whether for cloning, gene editing, or synthetic biology, this calculator is an indispensable resource for researchers aiming to push the boundaries of what’s possible in molecular biology.

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