How to use the qpcr fold change calculator
Find the fold change in gene expression from qPCR threshold cycle values using the ΔΔCt method. Enter target gene ct, treated, reference gene ct, treated, target gene ct, control, reference gene ct, control in the fields above; the fold change (2^-δδct), log2 fold change are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “qPCR fold change”, “delta delta Ct”, “gene expression fold change”, “calculate qpcr fold change”, “find fold change”.
Formula
Variables
- ctT — Target gene Ct, treated (cycles)
- ctR — Reference gene Ct, treated (cycles)
- ctT0 — Target gene Ct, control (cycles)
- ctR0 — Reference gene Ct, control (cycles)
Worked example
With target gene ct, treated = 24 cycles, reference gene ct, treated = 18 cycles, target gene ct, control = 26 cycles, reference gene ct, control = 18 cycles, the calculator gives fold change (2^-δδct) ≈ 4; log2 fold change ≈ 2.
Frequently asked questions
What is the qpcr fold change calculator used for?
Find the fold change in gene expression from qPCR threshold cycle values using the ΔΔCt method. It helps with questions such as “qPCR fold change”, “delta delta Ct”, “gene expression fold change”.
What is the formula for the qpcr fold change calculation?
Fold change (2^-ΔΔCt) = 2^(-((ctT-ctR)-(ctT0-ctR0))). Log2 fold change = -((ctT-ctR)-(ctT0-ctR0)). Here ctT is target gene ct, treated (cycles), ctR is reference gene ct, treated (cycles), ctT0 is target gene ct, control (cycles), ctR0 is reference gene ct, control (cycles).
What inputs do I need for the qpcr fold change (2^-δδct) calculator?
You need target gene ct, treated in cycles, reference gene ct, treated in cycles, target gene ct, control in cycles, reference gene ct, control in cycles. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the qpcr fold change calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the qpcr fold change result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.