1. What is the IDT Copy Number Calculator?

The IDT Copy Number Calculator estimates the number of DNA molecules in a given mass of DNA based on its length. This is essential for molecular biology applications like qPCR, sequencing, and cloning.

2. How Does the Calculator Work?

The calculator uses the IDT copy number formula:

Where:

• \( ng \) — Mass of DNA in nanograms
• \( bp \) — Length of DNA in base pairs
• \( 6.022 \times 10^{23} \) — Avogadro's number (molecules per mole)
• \( 650 \) — Average molecular weight of one DNA base pair (Daltons)

Explanation: The formula converts mass to moles using molecular weight, then to molecules using Avogadro's number.

3. Importance of Copy Number Calculation

Details: Accurate copy number calculation is crucial for quantitative PCR (qPCR) standards, next-generation sequencing library preparation, and ensuring consistent DNA input in reactions.

4. Using the Calculator

Tips: Enter DNA amount in nanograms (ng) and DNA length in base pairs (bp). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why use 650 Daltons per base pair?
A: This is the average molecular weight of a DNA base pair (sodium salt), accounting for both nucleotides and counterions.

Q2: How accurate is this calculation?
A: It provides a good estimate for most applications, though actual molecular weight may vary slightly based on sequence composition.

Q3: Can I use this for RNA?
A: No, RNA calculations require different molecular weight values (average ~340 g/mol per nucleotide for single-stranded RNA).

Q4: What's a typical copy number range for qPCR?
A: Standard curves often range from 10¹ to 10⁹ copies per reaction, depending on application sensitivity.

Q5: How do I convert from ng/μL to copy number/μL?
A: First calculate total ng in your volume, then use this calculator to determine copies in that volume.