Science & engineering calculators

A

• A260 concentration & purity calculator (A260/280, A260/230) | DNA/RNA | CalcBE
  Calculate DNA/RNA concentration (ng/µL, µg/mL) and purity ratios (A260/280, A260/230) from A260/A280/A230 and dilution. Includes dsDNA/RNA factor presets, total amount from volume, optional blank correction, CSV/LaTeX…
• Acid-base titration curve and pH calculator
  Free acid-base titration calculator for strong and weak acids and bases. Compute pH at any point and generate titration curves with step-by-step explanations.
• Acid–base pH calculator (strong & weak acids and bases) | CalcBE
  Solve pH and pOH for strong and weak acids and bases and for strong acid–strong base mixtures, with clear steps and shareable URLs.
• Acid–base titration curve calculator – pH vs volume with worked steps | CalcBE
  Plot strong and weak acid–base titration curves, highlight buffer regions and equivalence points, and review the Henderson–Hasselbalch or hydrolysis steps behind each segment.
• Astronomy calculators | CalcBE
  Astronomy calculators with clear steps that run in your browser.

B

• Beer-Lambert law calculator and calibration curve (A = εlc)
  Free online Beer-Lambert law calculator for absorbance, concentration, molar absorptivity, path length, and calibration curves. Great for general chemistry and lab reports.
• Biology calculators | CalcBE
  Biology calculators with step-by-step guidance for PCR, cloning, NGS, ecology, and genetics.
• Buffer pH (Henderson–Hasselbalch) with steps — design, additions, capacity | CalcBE
  Compute buffer pH with the Henderson–Hasselbalch equation, design mixtures for a target pH, and model strong acid/base additions with buffer capacity and step-by-step logs.

C

• Calorimetry calculator (specific heat, heat, final temperature)
  Free calorimetry calculator to find heat, specific heat, temperature change, and final equilibrium temperature when mixing two substances.
• Catalyst loading calculator – mol%, ppm, eq to mass/volume | CalcBE
  Convert catalyst loading between eq, mol% and ppm/ppb, calculate required mass or volume from a base amount, and share the setup by URL.
• Cell seeding calculator | cells/well → required volume | CalcBE
  Calculate required cell suspension and media volume from target cells/well (or cells/cm²), number of wells, volume, and stock concentration. Includes per-well volume, overage, viability correction, copy, CSV/LaTeX, an…
• CFU/mL calculator (dilution, plated volume) | from colony counts | CalcBE
  Calculate CFU/mL from dilution (e.g., 10^-6), plated volume (mL), and colony counts. Supports auto selection by guide range (30–300), manual selection, per-dilution summary, plots, logs, CSV/LaTeX, and share URLs.
• Chemical Equation Balancer + Stoichiometry (with steps) | CalcBE
  Chemical equation balancer with Gauss-Jordan steps. Compute limiting reagent, theoretical/percent yield, and balance redox half-reactions with shareable outputs.
• Chemical equilibrium ICE table calculator (Kc, Kp)
  Calculate equilibrium concentrations and a full ICE table from Kc or Kp and initial conditions for a single chemical reaction. Useful for general chemistry and lab reports.
• Chemistry Calculators | CalcBE
  Chemistry calculators for pH, titration curves, kinetics, equilibrium, and solutions. Step-by-step and browser‑only.
• Circular motion & centripetal force calculator
  Free circular motion calculator for centripetal acceleration, centripetal force, angular speed, period, frequency, and ideal banked-curve angle.
• Colligative properties calculator — boiling, freezing, osmotic | CalcBE
  Calculate boiling-point elevation, freezing-point depression, osmotic pressure, and molar mass from colligative measurements.
• Concentration & pH calculator – step-by-step chemistry working | CalcBE
  Calculate molarity, mass percent, M1V1 dilution, mixing, w/w→M, and strong or weak acid-base pH with 25 °C assumptions and a detailed step-by-step breakdown.

D

• Dimensional analysis & unit consistency checker (with steps) | CalcBE
  Parse compound units, verify equation consistency, and generate Buckingham Π groups with step-by-step logs, CSV export, and shareable URLs.
• Distance modulus calculator — m−M = 5 log10(d/10 pc) | CalcBE
  Distance modulus formula: m−M = 5 log10(d/10 pc). Compute distance, apparent magnitude, or absolute magnitude, plus a simple 1/r² brightness graph.
• Diversity index calculator (Shannon & Simpson) | ecology & microbiome | CalcBE
  Calculate diversity indices from category counts. Shows Shannon (ln/log2/log10) and Simpson (D, 1−D, 1/D) together, plus Hill numbers (q=0/1/2) and evenness (Pielou J). Supports examples, paste input, copy results, CS…
• DNA assembly mix calculator (Gibson/Golden Gate) | Auto mix volumes | CalcBE
  Calculate DNA assembly mix for Gibson or Golden Gate. From backbone/insert molar ratios, get required mass (ng) and volume (µL), plus remaining water for total reaction volume. Examples, table input, copy, CSV/JSON, s…
• DNA/RNA converter (ng/µL ↔ nM ↔ copies) | by length | CalcBE
  Convert between mass concentration (ng/µL), molar concentration (nM), and copy number (copies/µL) from DNA/RNA length and type. Shows approximate molecular weight, total amount from volume, CSV/LaTeX, and share URLs.

E

• Earth science calculators | CalcBE
  Earth science calculators with clear steps that run in your browser.
• Earthquake magnitude & energy comparison calculator | CalcBE
  Compare two earthquake magnitudes and compute the energy ratio using E2/E1 = 10^{1.5(M2 - M1)}, with intuitive explanations and a log-scale bar view.
• Electrochemical cell & Nernst equation calculator | CalcBE
  Compute standard cell potentials E°, standard ΔG°, equilibrium constants K, Nernst equation E under non-standard conditions, and concentration cell voltages with clear steps and shareable URLs.
• ELISA standard curve fitter (4PL/5PL) | calculate concentration from OD | CalcBE
  Fit 4PL/5PL to ELISA standards (concentration and OD/signal) and calculate unknown concentrations. Supports weighting (1/y, 1/y²), residuals, back-calculation (recovery), share URL, and CSV/JSON export. Runs in the br…
• Empirical formula calculator — molecular formula & steps | CalcBE
  Empirical formula calculator: compute the empirical formula from percent composition (or grams), combustion data, or hydrates, then scale to the molecular formula using molar mass. Step-by-step working included.

G

• Genetic drift simulator (Wright–Fisher) | allele frequency drift | CalcBE
  Simulate genetic drift with the Wright–Fisher model. From N, initial p0, generations, and replicates, visualize trajectories, final distribution, and fixation/loss rates. Includes selection, mutation, migration (advan…
• Growth curve fitter (exponential & logistic) | doubling time & K | CalcBE
  Fit exponential and logistic growth to time-series data and estimate growth rate r, doubling time, and carrying capacity K. View fitted curves, residuals, and model comparisons (RMSE/AIC) with CSV/LaTeX and share URL.

H

• Hardy–Weinberg equilibrium and chi-square calculator
  Check Hardy–Weinberg equilibrium from genotype counts or allele frequencies, and compute the chi-square statistic and expected genotype frequencies.
• Hemocytometer calculator (cells/mL & viability) | Trypan Blue | CalcBE
  Calculate cell concentration (cells/mL) and viability (%) from hemocytometer counts and dilution. Supports improved Neubauer (10^4 factor), examples, warnings, result copy, CSV/LaTeX, and share URLs.

I

• Ideal gas law calculator (PV = nRT & gas laws)
  Free ideal gas law calculator to solve PV = nRT, combined gas law problems, and gas density and molar mass with automatic unit conversions.

K

• Kepler's third law (orbital period) calculator | CalcBE
  Kepler's third law calculator: solve orbital period T or semi-major axis a, compare Solar System planets on an a–T chart, and view an orbit diagram — no sign-in.

L

• Lens & Mirror Equation — with steps and ray diagram | CalcBE
  Compute image distance, magnification, and principal rays for thin lenses or mirrors with a live How it's calculated log, CSV export, and shareable links.
• Lens and mirror equation & magnification calculator
  Free lens and mirror equation calculator for thin lenses and spherical mirrors. Compute image distance, magnification, and classify images as real or virtual, upright or inverted.
• Ligation molar ratio calculator | Vector:insert amounts | CalcBE
  Calculate required insert mass (ng) and volume (µL) from vector mass, length, and desired molar ratio (e.g., 1:3). Includes presets, copy, CSV/JSON, and share URL.

M

• Mendelian ratio chi-square test calculator | 3:1, 9:3:3:1 | CalcBE
  From observed counts and expected ratios (3:1, 9:3:3:1, etc.), calculate χ², df, and p-value. Includes expected counts, contributions, observed vs expected charts, steps, CSV/LaTeX, and share URL.
• Michaelis–Menten fitter (Km, Vmax) | nonlinear fit | CalcBE
  Estimate Km and Vmax by nonlinear fitting of the Michaelis–Menten equation from substrate [S] and initial rate v. Shows scatter + fit, residuals, and R²/RMSE (guide), with copy, CSV/LaTeX, and share URL.
• Momentum & 1D collision calculator
  Free physics calculator for 1D collisions using conservation of momentum and coefficient of restitution. Compute final velocities and energy loss with step-by-step explanations.
• Multistep yield planner – overall yield & bottlenecks | CalcBE
  Plan multi-step syntheses with per-step yields, compute overall yield forward or backward, highlight bottlenecks, and export tables or URLs.

N

• NGS coverage calculator (average depth) | required reads back-calculation | CalcBE
  Estimate average NGS coverage depth. Calculate depth from target size and read count (PE/SE) or total yield (Gb), with usable, mapping, on-target, and duplicate rates. Back-calculate required reads/Gb for target depth…
• NGS library concentration (ng/µL → nM) | dilution & pooling | CalcBE
  Convert NGS library concentration from ng/µL and fragment length to nM, then calculate normalization dilutions and pooling (equal volume or equal molar). Supports table input, examples, copy, CSV/JSON, and share URLs.

O

• Ohm's law and simple DC circuit calculator
  Free calculator for Ohm's law and simple DC circuits. Solve voltage, current, resistance, power, and equivalent resistance in series or parallel.

P

• Partial pressure & gas mixing calculator – Dalton's law | CalcBE
  Apply Dalton's law for gas mixtures, run two-tank isothermal mixing and wet-gas corrections, and compare ideal vs van der Waals pressure with clear logs, CSV export and shareable URLs.
• PCR master mix calculator | reactions, concentrations, overage | CalcBE
  Calculate PCR/qPCR master mix volumes from reaction volume/count and stock/final concentrations. Supports overage (% or +1), 96/384 wells, protocol text, CSV/JSON, and share URLs.
• Physics Calculators | CalcBE
  Physics calculators for waves, optics, motion, gases, energy, and circuits. All tools run locally in your browser.
• Primer Tm calculator | PCR annealing temperature guide | CalcBE
  Calculate primer Tm from DNA sequences (5'→3') and estimate annealing temperature (Ta). Switch between recommended nearest-neighbor and simple formulas, set Na+/primer concentration, enter forward/reverse pairs, and e…
• Projectile motion calculator (time of flight, range, height) | CalcBE
  Free projectile motion calculator to find time of flight, horizontal range, maximum height, and required launch speed for a target. Copy a shareable URL—runs in your browser.
• Punnett square generator (1- and 2-gene) | automatic ratios | CalcBE
  Generate a Punnett square from parent genotypes (AA/Aa/aa, AaBb, etc.) and summarize genotype proportions (%/ratio). Optionally show phenotype ratios (guide) assuming complete dominance. Includes examples, Markdown ta…

Q

• qPCR standard curve calculator (efficiency, R², unknowns) | CalcBE
  Build a qPCR standard curve from Quantity and Ct, calculate slope, intercept, R², and PCR efficiency (%). Back-calculate unknown quantities with residuals, 95% bands, step logs, CSV/LaTeX, and share URLs.

R

• RC / RL / RLC Calculator — time constant, cutoff, resonance & phase (with steps) | CalcBE
  Analyse RC, RL, and RLC networks with step-by-step formulas. Compute time constants, divider gain, resonance, and equivalent series or parallel values with shareable results.
• Reaction kinetics & half-life calculator | CalcBE
  Online reaction kinetics calculator for 0th, 1st and 2nd order reactions. Compute half-lives and rate constants, fit data and analyse Arrhenius plots.
• Reagent table & reaction scale – export CSV/TSV | CalcBE
  Create reagent tables from a base amount, convert equiv/mol%/ppm to mmol, grams, and mL, then export TSV/CSV or share a URL for lab notes.
• Resistor Color Code Calculator (4/5/6 Band) | CalcBE
  Decode 4/5/6-band resistor color codes (or get colors from a value). Shows tolerance, TCR, nearest E24/E96 values, and a shareable URL.

S

• Science & Engineering Calculators | CalcBE
  Physics, chemistry, astronomy, and electronics calculators with clear steps. Filter tools, use the A–Z index, and save favourites for quick access.
• Significant Figures & Scientific Notation Calculator (with steps) | CalcBE
  Count significant figures, convert to scientific notation, and apply rounding rules for + − × ÷ with step-by-step logs, CSV export, and textbook vs final rounding.
• Simple harmonic motion (SHM) calculator
  Free SHM calculator for a mass–spring oscillator and a small-angle pendulum. Compute period, angular frequency, max speed, acceleration, and energy with step-by-step formulas.
• Simple Harmonic Motion (SHM) simulator — with steps and energy | CalcBE
  Simulate spring-mass simple harmonic motion with analytic, Euler-Cromer, or RK4 steps, inspect omega, period, energy, shareable logs, plots, and CSV exports.
• Snell's law & total internal reflection calculator
  Interactive Snell's law calculator for refraction and critical angle, including total internal reflection checks and step-by-step explanation.
• Solubility product (Ksp) & precipitation calculator | CalcBE
  Compute molar solubility from Ksp, recover Ksp from measured solubility, test Q vs Ksp for precipitation, and explore simple fractional precipitation ranges with step-by-step explanations.
• Solution recipe calculator – volume & concentration | CalcBE
  Generate lab-ready solution recipes from solids or stock solutions, including simple and serial dilutions, with clear step-by-step instructions and shareable URLs.
• Standing waves calculator: vibrating strings and air columns
  Free standing wave calculator for strings and tubes. Enter length, tension & density or sound speed to list mode frequencies, wavelengths, and steps instantly.
• Stoichiometry calculator (limiting reactant & percent yield) | CalcBE
  From a balanced chemical equation, compute limiting reactant, theoretical yield, leftover amounts, and percent yield from moles or masses.

T

• Target yield calculator – back-calculate reagent table | CalcBE
  Enter a reaction and target product mass to back-calculate base and reagent amounts, with auto-balancing, steps, and shareable tables.
• Thermodynamic process & PV diagram calculator (ideal gas)
  Free thermodynamic process calculator for ideal gases. Compute work, ΔU, and heat for isothermal, isobaric, isochoric, adiabatic, and polytropic processes, and see the PV diagram.

V

• Voltage divider & LC resonance calculator – gain & cutoff | CalcBE
  Design DC voltage dividers with loading and reverse solves, and compute LC resonance, reactance, Q and bandwidth with SI prefixes, E-series rounding and CSV export for lab or hobby projects.

W

• Work, energy & power calculator
  Physics calculator for work, kinetic and potential energy changes, and average power. See how force, displacement, mass, speed and height relate in one place.

#

• ΔCt / ΔΔCt calculator (relative expression) | CalcBE
  Paste qPCR Ct values to calculate ΔCt/ΔΔCt and relative expression (2^-ΔΔCt). Supports calibrator selection, multiple reference genes, Pfaffl efficiency correction, plots, step logs, CSV/LaTeX, and share URLs.