LOD / LOQ Calculator
LOD = k(LOD) × σ / S, LOQ = k(LOQ) × σ / S
Limit of detection and limit of quantitation from a standard deviation estimate and the calibration slope, with editable coefficients.
Inputs
From the calibration curve calculator, in response per concentration unit.
Calculation
Model
LOD = k(LOD) × σ / S, LOQ = k(LOQ) × σ / S
σ used
0.0025 — Residual standard deviation of the calibration line (Sy/x)
Calibration slope
S = 0.0412
LOD
3.3 × 0.0025 / 0.0412
0.200243 mg/L
LOQ
10 × 0.0025 / 0.0412
0.606796 mg/L
Inputs
- σ
- 0.0025
- σ source
- Residual standard deviation of the calibration line (Sy/x)
- Slope (S)
- 0.0412
- k(LOD)
- 3.3
- k(LOQ)
- 10
The coefficients 3.3 and 10 are widely used conventions, not universal requirements. Both are editable and the values used are shown above.
The meaning of σ differs between definitions (blank noise, residual standard deviation, intercept standard deviation). Your choice is recorded above.
Results are expressed in the concentration units of the calibration slope. LabCalc makes no regulatory or validation claim.
About this calculator
Detection and quantitation limits are estimated from the noise in the measurement (σ) and the sensitivity of the method (the calibration slope, S). The coefficients 3.3 and 10 are widely used conventions rather than universal requirements, so both are editable and the values used appear in the result.
What σ means differs between definitions — blank noise, the residual standard deviation of the calibration line, or the standard deviation of the intercept. Record your choice; it is carried through to the result. LabCalc makes no regulatory or validation claim.
LabCalc is provided as a calculation aid. Users remain responsible for verifying calculations, units, chemical compatibility, experimental procedures and applicable safety requirements before laboratory use.