All tools
All online calculators
Browse every calculator by category. Use this page as the main directory when moving between topics.
Biology
DNA, genetics, cell biology, and lab calculation tools for students and researchers.
Hardy-Weinberg Calculator
Calculate allele and genotype frequencies for a population in genetic equilibrium.
DNA GC Content Calculator
Calculate the percentage of guanine and cytosine bases in a DNA sequence.
Cell Doubling Time Calculator
Find the time required for a cell population to double in size.
Beer-Lambert Law Calculator
Calculate absorbance or concentration using the Beer-Lambert law.
Enzyme Kinetics Calculator
Calculate reaction velocity using the Michaelis-Menten equation.
Osmolarity Calculator
Estimate the osmolarity of a solution from solute concentration and dissociation.
Population Growth Calculator
Model exponential population growth over time in ecology.
Mendelian Genetics Calculator
Determine genotype and phenotype ratios for monohybrid crosses.
Allele Frequency Calculator
Calculate allele frequencies and heterozygosity from genotype counts.
PCR Efficiency Calculator
Calculate qPCR amplification efficiency from a standard curve slope.
Protein Molecular Weight Estimator
Estimate the molecular weight of a protein from its amino acid count.
Chi-Square Genetics Test Calculator
Test whether observed genetic counts fit an expected Mendelian ratio.
LOD Score Calculator
Estimate the logarithm of odds score used in genetic linkage analysis.
DNA Melting Temperature Calculator
Estimate DNA or oligo melting temperature for primers and short sequences.
PCR Primer Design Calculator
Check PCR primer length, GC content, Tm, 3' clamp, and annealing temperature.
Codon Usage Calculator
Paste a coding sequence to calculate codon frequency, per-thousand usage, amino acid counts, and GC3.
Cell Count / Hemocytometer Calculator
Calculate cells per mL, total cells, and live cell concentration from hemocytometer counts, dilution factor, chamber dimensions, volume, and viability.
Mitotic Index Calculator
Calculate overall and field-level mitotic index from mitotic cell counts and total cell counts across one or more microscope fields.
Cell Surface Area to Volume Calculator
Calculate surface area, volume, and SA:V for sphere, cube, cylinder, rectangular prism, or custom measurements.
Logistic Growth Model Calculator
Model logistic population growth with carrying capacity, K percentage, inflection point, and a time-series growth table.
Shannon Diversity Index Calculator
Calculate Shannon H', evenness, richness, effective species, and per-species contribution from abundance counts.
Simpson's Diversity Index Calculator
Calculate Simpson 1-D, dominance D, reciprocal index, richness, and species-level contribution from abundance counts.
Mark-Recapture Estimate Calculator
Estimate population size from mark-recapture data with Chapman estimate, Lincoln-Petersen estimate, standard error, and recapture rate.
Carrying Capacity Calculator
Estimate carrying capacity K from current population, growth rate, observed population change, and logistic growth assumptions.
pH Buffer Calculator
Calculate buffer pH, base/acid ratio, buffer range, and target pH recipe with the Henderson-Hasselbalch equation.
Protein Concentration (A280) Calculator
Calculate protein concentration from A280, extinction coefficient, path length, dilution factor, molecular weight, sample volume, and A260/A280 check.
Enzyme Activity Calculator
Calculate enzyme units, stock activity, and specific activity from product concentration, reaction volume, time, diluted enzyme volume, dilution factor, and original stock protein concentration.
Natural Selection Simulation Calculator
Simulate allele frequency change across generations from initial p and genotype fitness values for AA, Aa, and aa.
Genetic Drift Calculator
Estimate drift variance, allele frequency range, heterozygosity retention, fixation probability, and loss probability in a finite effective population.
Effective Population Size (Ne) Calculator
Calculate effective population size from breeding male and female counts.
Photosynthesis Rate Calculator
Calculate and normalize photosynthesis rate from oxygen production or carbon dioxide uptake.
Respiratory Quotient (RQ) Calculator
Calculate respiratory quotient from carbon dioxide output and oxygen uptake.
BMR Calculator
Estimate basal metabolic rate from age, height, weight, and sex.
VO2 Max Estimator
Estimate maximal oxygen uptake from fitness test measurements.
Health
BMI, calories, heart rate, and key wellbeing estimators.
BMI Calculator
Estimate body mass index using height and weight.
Calorie Calculator
Estimate daily calorie needs from profile and activity level.
Body Fat Calculator
Estimate body fat percentage from circumference and profile values.
Body Shape Calculator
Estimate a common body shape category from bust, waist, high hip, and hip measurements.
Steps to Miles Calculator
Convert step counts to miles, kilometers, stride length, and walking time.
Education
Grade, GPA, test score, and study planning calculators for students.
Finals Calculator
Find the final exam score you need to reach a target course grade.
MCAT Score Calculator
Estimate MCAT section scores, total score, and percentile from raw correct answers.
Words Per Minute Calculator
Calculate typing, reading, speaking, or fluency speed, plus accuracy and estimated time from a target WPM.
Math
Algebra, geometry, percentages, and common formula helpers.
Physics
Motion, force, pressure, and engineering quick computations.
Force Calculator
Calculate force from mass and acceleration.
Kinetic Energy Calculator
Compute kinetic energy from mass and velocity.
Ohm's Law Calculator
Solve voltage, current, or resistance from two known values.
Finance
Loans, ROI, savings growth, and budgeting calculations.
Hourly to Salary Calculator
Convert hourly pay to annual, monthly, biweekly, weekly, and daily pay.
Salary to Hourly Calculator
Convert annual salary to an hourly wage and pay-period equivalents.
Time and a Half Calculator
Calculate overtime rate, overtime pay, weekly gross pay, and annual estimate.
Japanese Invoice Tax Calculator
Estimate Japanese consumption tax totals by invoice line, with 8% and 10% rate summaries.
Loan Payment Calculator
Estimate monthly payment for a fixed-rate loan.
Compound Interest Calculator
Forecast investment growth with compound returns.
VAT Calculator
Add VAT, remove VAT, split VAT-included prices, and calculate net, tax, and gross totals.
Everyday life
Time, dates, unit conversion, and practical daily tools.
Birthday Countdown Calculator
Find your next birthday, days remaining, weekday, and age turning.
Days From Today Calculator
Find the date 30, 45, 90, or any number of days from today or from a custom start date.
Discount Calculator
Calculate sale price, savings, tax, and final total after a percent discount.
Days Between Two Dates Calculator
Calculate calendar days, business days, working days, weekends, and time duration between two dates.
Tip Calculator
Calculate tip, tax, grand total, and total per person with pre-tax or post-tax tipping.
Unit Converter
Convert common length, weight, temperature, volume, area, speed, electricity, cooking, height, and power units quickly.
Cooking
Kitchen conversion, baking weights, recipe measurements, and ingredient tools.
Grams to Cups Converter
Convert grams to cups, tablespoons, and teaspoons by ingredient.
Cups to Grams Converter
Convert cup measurements to grams for common baking ingredients.
Grams to Tablespoons Converter
Convert small gram amounts to tablespoons using ingredient density.
Grams to Teaspoons Converter
Convert grams to teaspoons for small kitchen ingredient amounts.
Chemistry
Molar mass, concentration, reaction rates, and pH utilities.
Dilution Calculator
Find the required volume to dilute a chemical stock solution, reagent, buffer, or lab solution.
Molarity Calculator
Find molarity from moles of solute and solution volume.
pH Calculator
Convert between pH, pOH, [H+], and [OH-], or estimate pH after a simple strong acid/base dilution.
Construction
Concrete volume, material estimates, and geometry for building.
Cubic Feet Calculator
Calculate cubic feet for boxes, rooms, cylinders, soil, and storage volume.
Electrical Conduit Fill Calculator
Estimate conduit fill percentage, allowed fill, pass/fail status, and minimum larger conduit size.
Solar Cable Sizing Calculator
Estimate solar DC cable size from current, distance, voltage, material, and target voltage drop.
Concrete Calculator
Estimate concrete volume for slabs, footings, and pours.
Tile Calculator
Estimate tile quantity including wastage margin.
Statistics
Standard deviation, sample size, confidence intervals, and tests.
Standard Deviation Calculator
Calculate sample or population standard deviation from a raw data list, with variance, mean, standard error, and quartiles.
Sample Size Calculator
Estimate survey sample size from confidence level, margin of error, expected proportion, population size, and response rate.
Other
Symbol, text, novelty, and niche calculation tools that do not fit a standard category.