Use this chemistry calculator to reproduce a named relationship with explicit quantities and units for study, laboratory planning, or an independent numerical check.

Total width at 5% height (min)

Required number input.

Front half width (min)

Required number input.

Compute the USP tailing factor as the total peak width at five percent height divided by twice the front half width. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Tailing factor

The resulting tailing factor returned as a number.

• Chromatographic plate, resolution, retention, and peak-shape formulas summarize an observed chromatogram. They do not model detector response, integration choices, extra-column broadening, gradient elution, overload, or uncertainty in locating peak boundaries.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check units and significant figures, compare the result with limiting cases, and use measured or source-specific constants where available. Laboratory, safety, and regulatory decisions require validated methods and appropriate uncertainty analysis.

• Peak Asymmetry Factor

  Compute the peak asymmetry factor as the tail half width divided by the front half width measured at ten percent peak height.

• Chromatographic Resolution

  Compute chromatographic resolution Rs as twice the retention time separation divided by the summed baseline peak widths.

• Selectivity Alpha

  Compute chromatographic selectivity alpha as the retention factor of peak B divided by the retention factor of peak A.