Bbiochemtools
52 free tools · no signup · shows every step

Biochem tools that show their work

Most study sites give you an answer or a cheat sheet. These teach you the method, live and step by step, so you can do it yourself on the exam.

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Biochemistry

Biochem & MCAT equation sheet

Every formula grouped by topic, with what it actually means and a calculator that solves it. Filter, search, and print.

"mcat equation sheet" →

Amino acid chart (all 20)

Every amino acid with codes, class, pKa values, pI, molecular weight, hydropathy, and essential status. Filter, search, and sort.

"amino acid chart" →

Peptide charge & pI calculator

Net charge at any pH, the isoelectric point, a titration curve, and the full Henderson-Hasselbalch breakdown for every ionizable group.

"how to calculate the pI of a peptide" →

Protein MW & extinction coefficient

Paste an amino acid sequence for its molecular weight, 280 nm extinction coefficient, the A280 of 1 mg/mL, theoretical pI, and full composition.

"protein molecular weight from sequence" →

Enzyme kinetics simulator

Michaelis-Menten and Lineweaver-Burk plots, live, with competitive / noncompetitive / uncompetitive inhibition and the worked Km and Vmax.

"competitive vs noncompetitive inhibition" →

Michaelis-Menten fitter

Paste your enzyme-lab data and instantly get Km, Vmax, and R² with a curve fitted through your points and the regression done for you.

"find Km and Vmax from data" →

Amino acid titration curve

Pick an amino acid and see its full titration curve with every buffering region and the pI marked, and worked.

"amino acid titration curve" →

Amino acid quiz

Drill all 20 amino acids on one-letter codes, three-letter codes, and class, with instant scoring and a reference table.

"amino acid quiz" →

Amino acid catabolism explorer

Ketogenic vs. glucogenic for all 20 amino acids, plus the full urea cycle with nitrogen atoms tracked.

"which amino acids are purely ketogenic" →

Molecular biology

Codon chart (genetic code)

All 64 codons colour-coded by amino acid class, start and stop marked. Switch RNA/DNA and click an amino acid to see every codon for it.

"codon chart" →

DNA → protein translation

Transcribe and translate any DNA sequence step by step. See the mRNA, the codons, and the protein with start and stop highlighted, plus the full codon table.

"translate DNA to protein" →

DNA melting temp & GC

Paste a primer and get its Tm, GC content, base composition, and reverse complement instantly, with the formula shown.

"primer melting temperature" →

DNA & RNA concentration (A260)

Concentration from an A260 reading, plus the 260/280 and 260/230 purity ratios and what they mean.

"a260 a280 ratio dna concentration" →

Glycolysis pathway explorer

Step through all 10 reactions with a live ATP/NADH tally, every enzyme named, and the three regulated steps highlighted.

"glycolysis steps and net ATP" →

How many ATP does glycolysis make?

Net 2 per glucose, 4 made and 2 spent. The exact steps that use ATP and the ones that make it, plus what changes without oxygen.

"glycolysis steps and net ATP" →

ATP yield calculator

Total ATP per glucose from glycolysis, the TCA cycle, and oxidative phosphorylation. See why textbooks say 30, 32, 36, or 38.

"how many ATP from one glucose" →

Citric acid cycle explorer

Step through all 8 reactions of the TCA cycle with a live NADH/FADH₂/GTP tally and the three regulated steps highlighted.

"citric acid cycle steps" →

Beta-oxidation ATP calculator

Enter any fatty acid's chain length and get total ATP yield from β-oxidation and the TCA cycle, every cycle shown.

"how many ATP from fatty acid oxidation" →

Gene expression regulation explorer

Simulate the lac operon under all 4 glucose/lactose conditions, compare it to the trp operon and eukaryotic control.

"lac operon glucose lactose truth table" →

Genetics

Punnett square solver

Type two genotypes and get the full square plus genotype and phenotype ratios, monohybrid and dihybrid.

"dihybrid cross calculator" →

Punnett square practice problems

A fresh worksheet every click. Blank grids, monohybrid through dihybrid, with a full answer key you can print or leave off.

"punnett square practice worksheet" →

Eye color Punnett square

The classic brown/blue square, plus the honest part: eye colour is polygenic, so two blue-eyed parents really can have a brown-eyed child.

"eye color punnett square" →

Dihybrid cross calculator

Two genes at once. The full 16-box square with gametes, genotype and phenotype ratios, and why it comes out 9:3:3:1.

"dihybrid cross punnett square" →

Blood type Punnett square

Two parent blood types in, every possible child type and the odds out. Handles ABO codominance, unknown genotypes and Rh factor.

"blood type punnett square" →

Blood type inheritance

Pick two parents' ABO and Rh genotypes to see every possible child blood type, its probability, and the Punnett square. Codominance shown.

"blood type calculator" →

X-linked inheritance

Cross a mother and father for a sex-linked trait like colorblindness to see affected, carrier, and unaffected sons and daughters, with the Punnett square.

"x linked inheritance calculator" →

Chi-square genetic ratio

Test whether observed cross counts fit an expected ratio like 3:1 or 9:3:3:1, with the chi-square value, degrees of freedom, a real p-value, and a verdict.

"chi square calculator genetics" →

Hardy-Weinberg calculator

Allele and genotype frequencies from p or from counts, plus a chi-square equilibrium test, fully worked.

"hardy weinberg calculator" →

How to calculate allele frequency

Count alleles, not individuals. Worked from genotype counts, with the equilibrium check and why the square root shortcut misleads.

"how to calculate allele frequency" →

Chemistry

pH calculator

pH, pOH, [H⁺], and [OH⁻] for strong and weak acids and bases, solved exactly, with every step shown.

"pH of a weak acid" →

Buffer calculator

Exact acid and conjugate-base amounts to hit any target pH, with the full worked math and a buffering-range check.

"how to make a buffer at a given pH" →

Acid-base titration curve

Plot pH vs titrant volume for any strong or weak acid or base, with the equivalence point, half-equivalence (pKa), and buffer region marked.

"titration curve calculator" →

Gibbs free energy

Is the reaction spontaneous? Compute ΔG from ΔH/ΔS/T or from ΔG°′ and Q, with the crossover temperature.

"is the reaction spontaneous" →

Nernst equation

Cell potential from E°, n, and Q at any temperature, with both the RT/nF and 0.0592/n forms shown.

"nernst equation calculator" →

Beer-Lambert calculator

Absorbance ↔ concentration with A = εbc, plus an absorbance/%transmittance converter, fully worked.

"absorbance to concentration" →

Ideal gas law (PV = nRT)

Solve for pressure, volume, moles, or temperature with the right gas constant and every step shown.

"ideal gas law calculator" →

Chemical equilibrium (Keq)

Solve an ICE table for Keq, compare Q vs K to predict shift direction, and convert Keq straight to ΔG°.

"ice table solver keq" →

Reaction half-life & rate law

Zero, first, and second order kinetics: the half-life, concentration at any time from the integrated rate law, and a live decay plot.

"first order half life calculator" →

Percent yield calculator

Theoretical yield from the limiting reactant and mole ratio, then percent yield from your actual yield, every step shown.

"how to calculate percent yield" →

Percent composition

Enter any chemical formula for the mass percent of every element, the molar mass, and each element's contribution, fully worked.

"percent composition calculator" →

Limiting reagent calculator

Enter two reactants and coefficients to find which runs out first and how much excess is left over, every step shown.

"how to find the limiting reactant" →

Empirical formula calculator

Turn percent composition or masses into the empirical formula, then the molecular formula from molar mass.

"how to find empirical formula" →

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Why these are different

A calculator gives you a number. A cheat sheet gives you facts to memorize. Neither teaches you the method, which is what you need when there's no calculator on the exam.

Shows the work

Every tool walks through the actual method step by step as you change the inputs, not just a final number.

Free, no signup

No account, no paywall, no email capture. Open a tool and use it, that's the whole flow.

Built for MCAT

Every formula, worked example, and practice problem is scoped to what pre-med and MCAT courses actually test.