Biology Calculators
194 calculators across all biology domains
Hardy-Weinberg Equilibrium
Calculate allele frequencies under HWE
p² + 2pq + q² = 1
Allele Frequency Calculator
Calculate allele frequencies from genotype counts
p = (2n_AA + n_Aa)/(2N), q = 1-p
Punnett Square (Monohybrid)
Calculate offspring genotype ratios from a monohybrid cross
Aa × Aa → 1:2:1 genotype ratio
Genome Coverage Calculator
Calculate sequencing depth coverage
Coverage = (read_length × read_count) / genome_size
Primer Melting Temperature (Tm)
Calculate Tm for DNA primers using %GC method
Tm = 64.9 + 41×(G+C-16.4)/(A+T+G+C)
GC Content Calculator
Calculate GC percentage of a DNA sequence
GC% = (G+C)/(A+T+G+C) × 100%
PCR Master Mix Calculator
Calculate volumes needed for PCR reaction
V_total = ΣV_components
Codon Frequency
Calculate codon usage frequency
Frequency per thousand codons
Genetic Map Distance (cM)
Calculate recombination frequency and map distance
cM = RF × 100
Linkage Disequilibrium (D)
Calculate LD between two loci
D = P_AB - P_A × P_B
Simpson's Diversity Index
Calculate species diversity in a community
D = 1 - Σ(n/N)²
Shannon-Wiener Index
Calculate species diversity using Shannon index
H' = -Σp_i × ln(p_i)
Mark-Recapture (Lincoln-Petersen)
Estimate population size
N = (M × C)/R
Exponential Population Growth
Calculate population size after time t
N(t) = N₀e^(rt)
Logistic Population Growth
Calculate population with carrying capacity
dN/dt = rN(1 - N/K)
Species Richness (Margalef)
Calculate species richness index
R = (S-1)/ln(N)
Trophic Level Energy Transfer
Calculate energy at each trophic level
E_n = E₀ × (TE)ⁿ
Population Doubling Time
Calculate time for population to double
t₂ = ln(2)/r
Species-Area Relationship
Predict number of species on an island
S = c × A^z
Cardiac Output
Calculate cardiac output from heart rate and stroke volume
CO = HR × SV
GFR (CKD-EPI Equation)
Estimated glomerular filtration rate
CKD-EPI equation
Body Surface Area (BSA)
Calculate BSA using Mosteller formula
BSA = √(height × weight / 3600)
Mean Arterial Pressure (MAP)
Calculate MAP from systolic and diastolic BP
MAP = DP + ⅓(SP - DP)
VO₂ Max (Non-exercise)
Estimate VO₂ max from age, gender, BMI
VO₂max = 56.363 - 0.369 × age...
Anion Gap
Calculate anion gap from electrolytes
AG = Na⁺ - (Cl⁻ + HCO₃⁻)
Plasma Osmolarity
Calculate plasma osmolarity
Osm = 2Na + Glucose/18 + BUN/2.8
Tidal Volume (IBW)
Calculate ideal tidal volume from height
Vt = 6-8 mL/kg IBW
Alveolar Gas Equation
Calculate alveolar oxygen partial pressure
P_AO₂ = P_IO₂ - PaCO₂/RQ
Nerve Conduction Velocity
Calculate nerve conduction velocity
v = distance/time
Michaelis-Menten Kinetics
Calculate reaction velocity from substrate concentration
V = Vmax × [S]/(Km + [S])
Lineweaver-Burk Plot
Calculate 1/V from 1/[S] for Lineweaver-Burk plot
1/V = Km/Vmax × 1/[S] + 1/Vmax
Protein Molecular Weight
Estimate protein MW from number of amino acids
MW ~ 110 × n (average)
Enzyme Specific Activity
Calculate specific activity of an enzyme
SA = activity / protein_mass
Binding Affinity (Kd Calculator)
Calculate dissociation constant from binding data
Kd = [L] at half-max binding
IC₅₀ Calculator (Hill Equation)
Calculate inhibition percentage at given concentration
Response = 100/(1 + (IC₅₀/[I])^n)
Turnover Number (kcat)
Calculate kcat from Vmax and enzyme concentration
kcat = Vmax/[E]ₜ
Beer-Lambert (Biochemistry)
Calculate protein concentration from A₂₈₀
c = A/(ε × l)
CFU/mL Calculator
Calculate colony-forming units per mL
CFU/mL = colonies / (dilution × volume)
Bacterial Doubling Time
Calculate doubling time from growth curve
t_d = ln(2) / k
MIC (Minimum Inhibitory Concentration)
Determine MIC from dilution series
Lowest concentration with no growth
Serial Dilution Calculator
Calculate concentration after serial dilutions
C_final = C_initial × DFⁿ
Viable Cell Count (Trypan Blue)
Calculate viable cell count and viability
Viability = live/(live+dead) × 100%
Mutation Frequency
Calculate mutation frequency
MF = mutants / total_cells
dN/dS Ratio
Calculate ratio of nonsynonymous to synonymous substitutions
ω = dN/dS
Molecular Clock
Calculate divergence time from genetic distance
T = d/(2μ)
Fixation Index (Fst)
Calculate population differentiation from Fst
Fst = 1 - Hs/Ht
Nucleotide Diversity (π)
Calculate average pairwise nucleotide diversity
π = Σ(differences)/(n×(n-1)/2)
Effective Population Size (Ne)
Estimate effective population size from census size
Ne = (4NmNf)/(Nm+Nf)
Heritability (h²)
Calculate heritability from parent-offspring regression
h² = slope of offspring vs parent
Selection Coefficient (s)
Calculate selection coefficient from fitness
s = 1 - w
Neural Spike Frequency
Calculate firing rate from spike count
f = spikes/time
Synaptic Strength
Calculate synaptic strength change (STDP)
Δw = A × exp(-Δt/τ)
EEG Band Power
Calculate EEG frequency band power
Power from spectral analysis
Leaf Area Index (LAI)
Calculate LAI from light interception
LAI = -ln(1-f)/k
Photosynthetic Rate (Net)
Calculate net photosynthetic rate from CO₂ exchange
Pn = (CO₂_in - CO₂_out) × flow/leaf_area
Water Use Efficiency (WUE)
Calculate WUE from photosynthesis and transpiration
WUE = Pn/E
Relative Growth Rate (RGR)
Calculate plant growth rate
RGR = (ln W₂ - ln W₁)/(t₂-t₁)
Seed Germination Rate
Calculate seed germination percentage
% = (germinated/total) × 100%
Stomatal Conductance
Calculate stomatal conductance from leaf temperature
g_s = E/(D × VPD)
Body Mass Index (BMI)
Calculate BMI from height and weight
BMI = kg/m²
Blood Pressure Classification
Classify blood pressure reading
Systolic/Diastolic classification
Cholesterol Ratio
Calculate total cholesterol/HDL ratio
Ratio = Total/HDL
AST/ALT Ratio (De Ritis)
Calculate AST/ALT ratio for liver assessment
AST/ALT ratio
Corrected Calcium
Calculate corrected calcium for low albumin
Ca_corr = Ca + 0.8×(4 - Albumin)
QALY Calculator
Calculate Quality-Adjusted Life Years
QALY = Life Years × Utility
LD₅₀ Converter
Convert LD₅₀ between units
Conversion for toxicology
Tumor Doubling Time
Calculate tumor volume doubling time
VDT = t × ln(2)/ln(V₂/V₁)
Ecological Footprint
Estimate personal ecological footprint (simplified)
Carbon + food + housing + transport
Ponderal Index
Calculate ponderal index
PI = kg/m³
Metabolic Syndrome Check
Check metabolic syndrome criteria
ATP III criteria
Herd Immunity Threshold
Calculate the vaccination coverage needed to achieve herd immunity
HIT = (1 - 1/R₀) / VE
Viral Titer (PFU/mL)
Calculate viral titer from plaque assay results
PFU/mL = plaques / (dilution × volume)
ELISA Titer Calculator
Calculate sample-to-cutoff ratio and estimate antibody titer
S/CO = Sample OD / Cutoff OD
Drug Half-Life Calculator
Calculate elimination half-life and rate constant from concentration data
t½ = -ln(2) × t / ln(Cₜ/C₀)
Creatinine Clearance (Cockcroft-Gault)
Estimate creatinine clearance for renal function assessment
CrCl = [(140-age)×wt]/(72×Cr) × 0.85 if female
Sensitivity & Specificity
Calculate diagnostic test performance metrics from 2x2 table
Sens = TP/(TP+FN), Spec = TN/(TN+FP)
Relative Risk & Odds Ratio
Calculate relative risk, odds ratio, and attributable risk from cohort data
RR = (a/(a+b))/(c/(c+d)), OR = ad/bc
Incidence Rate & Prevalence
Calculate disease prevalence and incidence rate
Prev = existing/pop, Inc = new/(pop × time)
qPCR ΔΔCt (Relative Quantification)
Calculate relative gene expression using the comparative Ct method
RQ = 2^(-ΔΔCt)
Hemocytometer Cell Count
Calculate cell concentration and viability using a hemocytometer
Cells/mL = (cells/grids) × dilution × 10⁴
Seeding Density Calculator
Calculate cell suspension volume needed for desired plating density
V = (density × area) / concentration
Restriction Enzyme Digest
Calculate enzyme volume needed for DNA restriction digest
Units needed = DNA (μg) × 5-10 U/μg
Feed Conversion Ratio (FCR)
Calculate feed efficiency in aquaculture and livestock
FCR = feed intake / weight gain
Dissolved Oxygen Saturation
Calculate DO saturation concentration and percent saturation
DO_sat = f(temp, salinity)
Coral Calcification Rate
Calculate coral calcification rate from buoyant weight
G = (W₂-W₁)/(t × SA)
Salinity Conversion
Convert between conductivity and practical salinity units
PSU from conductivity ratio
Water Quality Index (WQI)
Calculate simplified water quality index from key parameters
WQI = Σ(wi × qi)
Pielou's Evenness (J')
Calculate species evenness from Shannon diversity
J' = H'/ln(S)
Degree-Day Calculator (GDD)
Calculate growing degree days for plant and insect development
GDD = ((Tmax+Tmin)/2) - Tbase
Body Condition Index (BCI)
Estimate body condition from weight and length measurements
BCI = weight / length^b × k
Annealing Temperature Calculator
Estimate PCR annealing temperature from primer melting temperatures.
Ta = average(Tm) - 5
Generation Time Calculator
Calculate generation time from population growth.
g = t / log2(Nt/N0)
Cell Dilution Calculator
Calculate stock cell suspension and diluent volume.
C1V1 = C2V2
Cell Doubling Time Calculator
Calculate cell doubling time from starting and ending counts.
dt = t / log2(Nt/N0)
DNA Concentration Calculator
Estimate DNA concentration from A260 absorbance.
DNA = A260 x dilution x 50
Ligation Calculator
Calculate insert mass for a vector-to-insert molar ratio.
insert ng = vector ng x insert bp/vector bp x ratio
Log Reduction Calculator
Calculate microbial log reduction and percent reduction.
LR = log10(initial/final)
Protein Concentration Calculator
Estimate protein concentration from absorbance and standard factor.
conc = absorbance x factor x dilution
Dihybrid Cross Calculator - Punnett Square
Calculate phenotype probabilities for two independent traits.
P = P(A) x P(B)
DNA Copy Number Calculator
Convert DNA mass to approximate molecule copy number.
copies = mass x Avogadro / (bp x 660)
DNA to mRNA Converter
Convert DNA base counts to complementary mRNA base counts.
DNA A->U, T->A, G->C, C->G
qPCR Efficiency Calculator
Calculate qPCR amplification efficiency from standard curve slope.
E = (10^(-1/slope) - 1) x 100
Trihybrid Cross Calculator - Punnett Square
Calculate major phenotype probabilities for three independent traits.
P = P(A) x P(B) x P(C)
Cat Pregnancy Calculator
Estimate cat gestation progress and days remaining.
remaining = 65 - days_since_breeding
Cow Gestation Calculator
Estimate cow gestation progress and days remaining.
remaining = 283 - days_since_breeding
Dog Pregnancy Calculator
Estimate dog gestation progress and days remaining.
remaining = 63 - days_since_breeding
Goat Gestation Calculator
Estimate goat gestation progress and days remaining.
remaining = 150 - days_since_breeding
Guinea Pig Pregnancy Calculator
Estimate guinea pig gestation progress and days remaining.
remaining = 68 - days_since_breeding
Mare Gestation Calculator - Horse Gestation
Estimate mare gestation progress and days remaining.
remaining = 340 - days_since_breeding
Llama Calculator
Estimate llama gestation progress and days remaining.
remaining = 350 - days_since_breeding
Rabbit Gestation Calculator
Estimate rabbit gestation progress and days remaining.
remaining = 31 - days_since_breeding
Sheep Gestation Calculator
Estimate sheep gestation progress and days remaining.
remaining = 147 - days_since_breeding
Swine Gestation Calculator
Estimate swine gestation progress and days remaining.
remaining = 114 - days_since_breeding
Benadryl Dosage Calculator for Dogs
Estimate a dog dose range from body weight. Confirm all medication with a veterinarian.
dose = weight x mg_per_kg
Cephalexin For Dogs Dosage Calculator
Estimate a dog dose range from body weight. Confirm all medication with a veterinarian.
dose = weight x mg_per_kg
Metacam Dosage Calculator for Dogs
Estimate a dog dose range from body weight. Confirm all medication with a veterinarian.
dose = weight x mg_per_kg
Tramadol For Dogs Calculator
Estimate a dog dose range from body weight. Confirm all medication with a veterinarian.
dose = weight x mg_per_kg
Cost of Owning a Dog Calculator
Estimate lifetime dog ownership costs.
cost = upfront + years x annual_cost
Dog Age Calculator
Estimate dog age in human years from size-adjusted aging.
human_years = 16 ln(age) + 31
Dog BMI Calculator
Calculate a simple dog body mass index.
BMI = weight / height^2
Dog Nutrition Calculator
Estimate daily calories from resting energy requirement.
MER = 70 x kg^0.75 x factor
Dog Chocolate Toxicity Calculator
Estimate theobromine exposure from chocolate.
mg/kg = chocolate x theobromine / weight
Dog Crate Size Calculator
Estimate crate dimensions from dog measurements.
crate = dog size + clearance
Dog Food Calculator
Convert daily calories to cups or grams of food.
food = calories / food_density
Dog Harness Size Calculator
Estimate harness size from chest and neck girth.
fit = measurement + allowance
Dog Heat Cycle Calculator
Estimate the next heat cycle date offset.
next = interval - days_since_last
Dog Life Expectancy Calculator
Estimate remaining years from average breed lifespan.
remaining = lifespan - age
Dog Onion Toxicity Calculator
Estimate onion exposure by body weight.
g/kg = onion / weight
Dog Quality of Life Calculator
Score comfort, appetite, mobility, and mood.
score = sum of seven 0-10 ratings
Dog Raisin Toxicity Calculator
Estimate raisin exposure by body weight.
g/kg = raisins / weight
Dog Size Calculator
Estimate adult dog weight from current growth percentage.
adult = current / growth_percent
Dog Water Intake Calculator
Estimate daily dog water needs.
water = weight x 60 mL
Omega-3 For Dogs Calculator
Estimate omega-3 dose from body weight.
dose = weight x mg/kg
Quiz: Dog Size Calculator
Estimate adult dog size from a puppy weight quiz score.
adult = current / growth_percent
Raw Dog Food Calculator
Estimate raw food quantity by body weight.
food = weight x feed_percent
Cat Benadryl Dosage Calculator
Estimate a cat dose range from body weight. Confirm all medication with a veterinarian.
dose = weight x mg_per_kg
Cephalexin For Cats Dosage Calculator
Estimate a cat dose range from body weight. Confirm all medication with a veterinarian.
dose = weight x mg_per_kg
Metacam Dosage Calculator for Cats
Estimate a cat dose range from body weight. Confirm all medication with a veterinarian.
dose = weight x mg_per_kg
Cat Age Calculator
Estimate cat age in human years.
human_years = 24 + 4 x (age - 2)
Cat BMI Calculator
Calculate a simple feline body mass index.
BMI = weight / height^2
Cat Calorie Calculator
Estimate daily cat calories.
MER = 70 x kg^0.75 x factor
Cat Chocolate Toxicity Calculator
Estimate theobromine exposure for cats.
mg/kg = chocolate x theobromine / weight
Catculator
Estimate monthly cat care costs.
monthly = food + litter + vet + extras
Cat Quality of Life Calculator
Score feline quality of life factors.
score = sum of seven 0-10 ratings
Fish Oil Dosage Calculator For Cats
Estimate fish oil dose from EPA+DHA target.
oil = target / concentration
How Big Will My Cat Get Calculator
Estimate adult cat weight from growth progress.
adult = current / growth_percent
Quiz: Cat Age Calculator
Estimate cat human-age equivalent from age and maturity score.
human_years = base x maturity
Bird Age Calculator
Estimate bird age equivalent from species factor.
equivalent = age x factor
Crickets Chirping Thermometer
Estimate temperature from cricket chirps.
F = chirps in 14 sec + 40
Dry Matter Calculator
Convert as-fed nutrient percentage to dry matter basis.
DM basis = as-fed / dry matter fraction
Guinea Pig Years to Human Years Calculator
Estimate guinea pig age equivalent.
human years = guinea pig years x 12
Hamster Age Calculator
Estimate hamster age equivalent.
human years = hamster months x factor
Horse Weight Calculator
Estimate horse weight from heart girth and body length.
lb = girth^2 x length / 330
Rabbit Cage Size Calculator
Estimate minimum rabbit cage area.
area = rabbits x area_each
Rabbit Color Calculator
Estimate kit color probability from parent carrier rates.
probability = sire x dam
Rat Cage Calculator
Estimate cage volume capacity for pet rats.
capacity = volume / volume_per_rat
Turtle Tank Size Calculator
Estimate aquarium gallons for aquatic turtles.
gallons = shell inches x 10
Animal Mortality Rate Calculator
Calculate herd or flock mortality rate.
mortality = deaths / population
Cattle per Acre Calculator
Estimate stocking density for grazing.
head = acres x carrying_capacity
Grain Bin Calculator
Estimate cylindrical grain bin capacity.
bushels = volume / 1.244
Livestock Fence Cost Calculator
Estimate fence material and labor cost.
cost = length x cost_per_foot + gates
Acres Per Hour Calculator
Calculate field work rate from speed and implement width.
ac/h = speed x width / 8.25
Bulb Spacing Calculator
Estimate number of bulbs for a planting bed.
bulbs = area / spacing^2
CO2 Grow Room Calculator
Estimate CO2 needed to raise grow room concentration.
CO2 = volume x ppm change
Compost Calculator
Estimate compost volume for garden beds.
volume = area x depth
Corn Yield Calculator
Estimate corn yield from ears, kernel rows, and kernels per row.
yield = ears x rows x kernels x factor
Daily Light Integral Calculator
Calculate DLI from PPFD and photoperiod.
DLI = PPFD x hours x 0.0036
Fertilizer Calculator
Calculate fertilizer amount from nutrient target.
fertilizer = nutrient / analysis
GDU Calculator - Growing Degree Units
Calculate growing degree units for crops.
GDU = avg temp - base
Grain Conversion Calculator
Convert grain bushels to weight.
weight = bushels x test_weight
Grass Seed Calculator
Estimate grass seed needed for a lawn.
seed = area x rate
Lawn Mowing Cost Calculator
Estimate lawn mowing service cost.
cost = base + area rate
Mulch Calculator
Estimate mulch volume from area and depth.
volume = area x depth
Pine Straw Calculator
Estimate pine straw bales needed.
bales = area / coverage
Plant Population Calculator
Calculate plants per acre from row and in-row spacing.
plants/ac = 43560 / spacing area
Plant Spacing Calculator
Estimate number of plants from spacing.
plants = area / spacing area
Potting Soil Calculator
Estimate potting soil volume for containers.
volume = pi r^2 h
Sod Calculator
Estimate sod area and rolls.
rolls = area / roll_area
Soil Calculator
Estimate soil volume for a bed.
volume = area x depth
VPD Calculator (Vapor Pressure Deficit)
Calculate vapor pressure deficit from temperature and humidity.
VPD = SVP x (1 - RH)
Vegetable Seed Calculator
Estimate seeds needed with germination adjustment.
seeds = plants / germination
Vegetable Yield Calculator
Estimate harvest from plant count.
yield = plants x yield per plant
Water Potential Calculator
Calculate water potential from pressure and solute potential.
psi = pressure + solute
Water Soluble Fertilizer Calculator
Calculate fertilizer grams for a target ppm.
grams = ppm x liters / nutrient fraction / 1000
Basal Area Calculator
Calculate tree basal area from diameter.
BA = 0.005454 x DBH^2
Tree Leaves Calculator
Estimate total leaves from branch sampling.
leaves = avg per branch x branches
Tree Age Calculator
Estimate tree age from diameter and growth factor.
age = diameter x growth factor
Tree Diameter Calculator
Convert circumference to tree diameter.
diameter = circumference / pi
Tree Height Calculator
Estimate tree height using angle and distance.
height = distance x tan(angle) + eye height
Tree Spacing Calculator
Calculate trees per acre from spacing.
trees/ac = 43560 / spacing area
Tree Value Calculator
Estimate tree value from board feet and price.
value = board feet x price
MLVSS Calculator
Calculate mixed liquor volatile suspended solids fraction.
MLVSS = MLSS x volatile fraction
Pet Sitter Rates Calculator
Estimate pet sitting fees.
fee = visits x rate + extras
Wastewater Calculator
Calculate wastewater loading and removal.
load = flow x concentration x 8.34