Calibration Curve Calculator
Apply slope and intercept from a linear calibration to unknown sample signals with optional replicate averaging.
Used when no replicate list is provided.
Optional. Overrides the single signal field.
Average signal
0.22
Calculated concentration
17.917
How to Use This Calculator
Fit the calibration curve
Use standards to determine slope and intercept for the linear calibration (y = m x + b).
Enter sample signal
Provide the instrument response for the unknown. Use the replicate field to average several measurements.
Review concentration result
The calculator applies (y - b) / m to determine the analyte concentration.
Validate against QC samples
Compare predicted values with quality controls to confirm the calibration remains valid.
Formula
x = (y - b) / m
x is concentration, y measured signal, m slope, b intercept. Average replicate signals before applying the equation.
Example
With m = 0.012, b = 0.005, and average signal y = 0.22, concentration x = (0.22 - 0.005) / 0.012 about 17.9 units.
Full Description
Linear calibration curves convert instrument response to analyte concentration when detector output is proportional to concentration.
Incorporating replicate signals improves precision by reducing random noise and highlighting drift or outliers.
Frequently Asked Questions
Can I use absorbance as the signal?
Yes. Any linear detector output works as long as slope and intercept come from matching standards.
What if my calibration is forced through zero?
Set the intercept to zero and supply the slope. The calculator handles zero intercepts automatically.
How do I report uncertainty?
This tool does not propagate error. Use regression statistics to compute confidence intervals separately.
Can I convert units?
Apply unit conversions to slope or output manually. Ensure slope matches the desired concentration units.
Why normalize replicates?
Averaging replicates smooths random noise and improves quantitation, especially near the detection limit.