Biology

Ligation Calculator

Find insert mass for a target molar ratio.

Vector mass (ng)

Vector length (bp)

Insert length (bp)

Insert : vector molar ratio

Calculated Output

Insert mass needed (ng) 30

Formula: insert ng = ratio × (insert bp ÷ vector bp) × vector ng

Step-by-Step Breakdown

1. Values used:

2. Vector mass = 50 ng

3. Vector length = 5,000 bp

4. Insert length = 1,000 bp

5. Insert : vector molar ratio = 3

7. Insert mass needed = 30ng

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The math behind it

insert mass = ratio × (insert length ÷ vector length) × vector mass. A 3:1 insert:vector ratio is common.

50 ng vector (5 kb), 1 kb insert, 3:1 → 30 ng insert.

Best ratio?

Try 3:1 for standard cloning; 1:1 to 5:1 for difficult ligations.