Ligation Calculator

Find insert mass for a target molar ratio.

Vector mass (ng)

Vector length (bp)

Insert length (bp)

Insert : vector molar ratio

Insert mass needed (ng) 30

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

Step-by-step with your numbers:

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

Did we solve your problem today?

Calculate how much insert DNA to add for a chosen insert:vector ratio.

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.