Calibration Curve Calculator

Your details

Known concentrations of your calibration standards, separated by commas. Must match the order and count of the signals below.
Instrumental responses for each standard. Typically absorbance (Beer-Lambert) or fluorescence intensity.
Choose the unit for your concentration axis.
The instrumental reading for your unknown sample. The calculator back-calculates its concentration from the regression line.
The signal of a blank (zero-standard) replicate. Used to estimate the baseline noise for LOD and LOQ. If you have a blank standard in your list, enter its signal here too.
Standard deviation of repeated blank measurements. LOD = 3 * SD_blank / slope, LOQ = 10 * SD_blank / slope.
Unknown concentrationExcellent linearity (R² >= 0.999)
5.4971ug/mL

Back-calculated from (signal - intercept) / slope

Slope (sensitivity)0.0989
Intercept (background)0.00633
R-squared0.99986
LOD0.1213ug/mL
LOQ0.4044ug/mL
Number of standards6
0.99986 R^2
Poor<0.95Acceptable0.95-0.99Good0.99-0.999Excellent0.999+

Calibration line: y = 0.09890 x + 0.00633, R-squared = 0.99986.

  • R-squared is 0.99986, which meets or exceeds the 0.999 threshold required by most pharmacopoeial and environmental methods.
  • The unknown sample concentration is 5.4971 ug/mL, back-calculated from signal = 0.5500 using x = (y - 0.00633) / 0.09890.
  • LOD is 0.1213 ug/mL and LOQ is 0.4044 ug/mL. Concentrations reported below LOQ should be treated as semi-quantitative.

Next stepIf the unknown is near the top of your range, verify no detector saturation occurred; if near the bottom, ensure it is above the LOQ.

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