Calculators for everyday lab work.
Each one shows the formula it uses, starts with a worked example and updates as you type. Nothing you enter leaves your browser.
Solutions
Statistics
Mean, SD and %RSD
Precision of replicate results, such as system suitability injections.
OpenStandard curve (linear regression)
Slope, intercept and correlation coefficient for a calibration or linearity curve.
OpenAverage weight & weight variation
Average tablet weight and each tablet's % deviation from the average.
OpenMicrobial count (cfu per g or mL)
Colony-forming units per gram or millilitre from duplicate plate counts and the dilution.
OpenCarr's index & Hausner ratio
Powder flow indicators from bulk and tapped density.
OpenContent uniformity — acceptance value (AV)
Acceptance value for uniformity of dosage units from individual results in % of label claim.
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Assay
HPLC assay — % of label claim
External-standard assay of a tablet, with standard and sample diluted the same way.
OpenLoss on drying (LOD)
Percentage weight lost on drying, from the bottle and sample weights.
OpenWater content by Karl Fischer (volumetric)
Water content from titrant volume, titre (water equivalence factor) and sample weight.
OpenTablet friability
Percentage weight loss of tablets after tumbling in a friability drum.
OpenSpecific optical rotation
Specific rotation from the observed angle, tube length and concentration.
OpenEndotoxin limit & maximum valid dilution (MVD)
Endotoxin limit from K/M and the maximum valid dilution for the LAL test.
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Calibration
F0 value (steam sterilisation)
Lethality in equivalent minutes at 121.1 °C from temperatures logged at a fixed interval (z = 10 °C).
OpenCentrifuge RCF ↔ rpm
Relative centrifugal force (× g) from speed and rotor radius.
OpenPipette gravimetric check
Mean delivered volume, systematic error and random error (CV) from replicate weighings of water.
OpenFlow rate accuracy
Actual flow and % error from a timed volume collection (HPLC pump calibration).
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