Biochemistry Calculators for Fibre and Protein

Explore biochemistry calculators for estimating the composition of biological, food, and feed samples. The Crude Fibre calculator helps you determine fibre content from laboratory measurements, while the Crude Protein calculator estimates protein content from nitrogen analysis data. These tools are for students, laboratory technicians, and nutrition or agricultural researchers who need quick, consistent calculations. Enter your measured values to check results or compare samples; the accuracy of each estimate depends on the methods and data you use.

Crude Protein

Calculate crude protein percentage from Kjeldahl back-titration data. Enter the blank and sample NaOH titre values, NaOH normality, and sample weight.

Enzyme Turnover Number

Calculate the enzyme turnover number (kcat) from Vmax and the total active enzyme concentration [E]t. Enter your rate in any common unit and get kcat in s⁻¹, min⁻¹ or h⁻¹.

Michaelis–Menten

Calculate the initial reaction velocity of an enzyme-catalyzed reaction using the Michaelis–Menten equation. Enter substrate concentration, Km, and Vmax to get v0 and the fraction of Vmax.

Crude Fibre

Calculate crude fibre as a percentage of dry sample weight. Enter the crucible and residue weights before and after ashing, plus the original dry sample weight.

Isoelectric Point

Enter the pKa values of a molecule's acidic and basic groups to find its isoelectric point (pI) — the pH at which the net charge is zero. Based on Henderson-Hasselbalch charge fractions, with a per-group charge breakdown.

Biochemical Oxygen Demand

Calculate the 5-day biochemical oxygen demand (BOD₅) of a diluted water sample from initial and final dissolved oxygen, dilution fraction, and optional seed correction, following APHA Standard Methods 5210B.

Osmotic Pressure

Calculate the osmotic pressure of a solution from its molarity, temperature and the van 't Hoff factor using the van 't Hoff equation π = iMRT. Results are shown in atm, kPa, mmHg and psi.

DNA Melting Temperature

Estimate the melting temperature (Tm) of a DNA oligonucleotide from its sequence and salt concentration. Enter one strand (A, C, G, T) and the Na⁺ concentration to get the Tm and GC content.

Partition Coefficient

Enter the equilibrium concentrations of a solute in the organic and aqueous phases to get the partition coefficient P, log P, and the percentage of solute in each layer.