Developer Utilities
Small developer utilities that save a trip to a random website. Encode and decode Base64, explain a regex, build UTM links, generate QR codes and vCards, and more — the everyday helpers. Free in your browser, and available by API when you need them in a script.
Developer Utilities
Mutation-selection equilibrium calculator
recessive q = √(μ/s)
POST /bio/mutation-equilibrium-frequency$0.002Developer Utilities
mRNA to protein length calculator
amino acids, exclude stop
POST /bio/mrna-to-protein-length$0.002Developer Utilities
Bacterial exponential growth calculator
final N = N0×2^(t/g)
POST /bio/exponential-growth-final$0.002Developer Utilities
Ligation insert:vector ratio calculator
insert DNA mass
POST /bio/ligation-insert-vector-ratio$0.002Developer Utilities
PCR product yield copies calculator
theoretical DNA after n cycles
POST /bio/pcr-amplicon-copies$0.002Developer Utilities
Biomass yield coefficient calculator
Y_X/S = ΔX/ΔS g/g
POST /bio/biomass-yield-coefficient$0.002Developer Utilities
Serial dilution volumes calculator
sample and diluent per tube
POST /bio/serial-dilution-volumes$0.002Developer Utilities
Logistic growth rate calculator
instantaneous dN/dt from N, r and K
POST /bio/logistic-growth-rate-dndt$0.002Developer Utilities
Logistic growth calculator
population N(t) from N0, r, K, t
POST /bio/population-logistic-growth$0.002Developer Utilities
Species abundance proportions calculator
counts to p_i
POST /bio/species-abundance-proportions$0.002Developer Utilities
Fertilizer blend ratio calculator
NPK source masses for a field mix
POST /bio/fertilizer-blend-ratio$0.002Developer Utilities
Finite population growth rate calculator
λ from N or r
POST /bio/finite-growth-rate-lambda$0.002Developer Utilities
Leaf area index calculator
LAI from one-sided leaf and ground area
POST /bio/leaf-area-index$0.002Developer Utilities
Grain adjusted weight calculator
moisture shrink for fair trade
POST /bio/grain-adjusted-weight$0.002Developer Utilities
Manure nutrient application calculator
N-P-K from rate and analysis
POST /bio/manure-nutrient-application$0.002Developer Utilities
Dew point simple approximation calculator
Td = T−(100−RH)/5
POST /earth/dew-point-simple$0.002Developer Utilities
Vapor pressure deficit calculator
VPD from T and RH
POST /earth/vapor-pressure-deficit$0.002Developer Utilities
Altitude from pressure calculator
hypsometric ISA height
POST /earth/altitude-from-pressure-barometric$0.002Developer Utilities
Summer simmer index calculator
SSI from temperature and humidity
POST /earth/summer-simmer-index$0.002Developer Utilities
Beaufort number to wind speed range
knots and m/s, free
POST /earth/beaufort-to-wind-speed$0.002Developer Utilities
Freezing rain ice accretion calculator
radial ice on a conductor
POST /earth/freezing-rain-accretion$0.002Developer Utilities
UNEP aridity index calculator
P/PET dryland class
POST /earth/aridity-index-unep$0.002Developer Utilities
Rubidium-strontium radiometric age calculator
isochron slope to age
POST /earth/radiometric-age-rb-sr$0.002Developer Utilities
Natural gas carbon footprint calculator
kg CO2 from therms or m3
POST /earth/carbon-footprint-natural-gas$0.002Developer Utilities
Manning open-channel velocity calculator
V from n, R, S
POST /earth/manning-velocity$0.002Developer Utilities
Porosity from void ratio calculator
n = e/(1+e) and back
POST /earth/porosity-from-void-ratio$0.002Developer Utilities
Air quality index from nitrogen dioxide
EPA NO2 AQI
POST /earth/aqi-no2$0.002Developer Utilities
Solar battery charge time calculator
hours from Ah, current, efficiency
POST /earth/solar-charge-time$0.002Developer Utilities
Fog stability index calculator
FSI from T, Td and T850
POST /earth/fog-stability-index$0.002Developer Utilities
Frost risk index calculator
overnight T, dew point, clouds
POST /earth/frost-risk-index$0.002Developer Utilities
Solar water heater energy savings
kWh from demand, rise, fraction
POST /earth/solar-water-heater-savings$0.002Developer Utilities
Water heating energy calculator
energy to heat a water volume
POST /earth/water-heating-energy$0.002Developer Utilities
Temperature at depth calculator
geothermal gradient
POST /earth/geothermal-temperature-at-depth$0.002Developer Utilities
Monthly thermal amplitude calculator
max minus min mean temps
POST /earth/thermal-amplitude-series$0.002Developer Utilities
Cross-price elasticity of demand calculator
XED, free
POST /econ/cross-price-elasticity-demand$0.002Developer Utilities
Consumer surplus linear demand calculator
triangle CS
POST /econ/consumer-surplus-linear-demand$0.002Developer Utilities
Unit-elastic price calculator
revenue-max point on linear demand
POST /econ/unit-elastic-price$0.002Developer Utilities
Marginal cost from cost function calculator
MC = b + 2cQ
POST /econ/marginal-cost-from-cost-function$0.002Developer Utilities
Producer tax burden calculator
share of a per-unit tax on sellers
POST /econ/producer-tax-burden$0.002Developer Utilities
Shutdown-point price calculator
stop producing below min AVC
POST /econ/shutdown-point$0.002Developer Utilities
Total product from production function
TP, MP, AP and stages
POST /econ/total-product-from-function$0.002Developer Utilities
Bertrand duopoly equilibrium calculator
prices to MC
POST /econ/bertrand-duopoly-equilibrium$0.002Developer Utilities
N-firm concentration ratio calculator
CR_n from shares
POST /econ/concentration-ratio-crn$0.002Developer Utilities
Inflation rate from CPI calculator
cost of living, free
POST /econ/inflation-rate-from-cpi$0.002Developer Utilities
Money supply from MV=PQ
solve M = PQ/V
POST /econ/money-supply-mv-pq$0.002Developer Utilities
Compound annual GDP growth rate calculator
CAGR from two GDP levels
POST /econ/compound-growth-rate-gdp$0.002Developer Utilities
Purchasing power parity exchange rate calculator
implied FX as P / P*
POST /econ/purchasing-power-parity$0.002Developer Utilities
Autarky vs trade consumption calculator
welfare gain
POST /econ/autarky-vs-trade$0.002Developer Utilities
Tariff-quota equivalence calculator
quota or tariff equivalent
POST /econ/tariff-vs-quota-equivalent$0.002Developer Utilities
Real minimum wage calculator
nominal wage × (CPI base / CPI)
POST /econ/real-minimum-wage$0.002Developer Utilities
Saddle point game theory calculator
pure-strategy solution
POST /econ/saddle-point-game$0.002Developer Utilities
Gini before vs after tax
redistribution calculator
POST /econ/gini-tax-redistribution$0.002Developer Utilities
Profit at given output calculator
π(Q) = TR − TC, free
POST /econ/profit-at-output$0.002Developer Utilities
Bell curve grade calculator
A–F from score, mean, σ
POST /edu/bell-curve-grade$0.002Developer Utilities
Final exam grade needed calculator
score to hit your target
POST /edu/final-exam-grade-needed$0.002Developer Utilities
Exam T-score calculator
convert z-score to T (mean 50, SD 10)
POST /edu/exam-t-score$0.002Developer Utilities
Overall grade from categories
weighted course % and letter
POST /edu/overall-from-categories$0.002Developer Utilities
Unweighted GPA calculator
4.0 scale, every course equal
POST /edu/unweighted-gpa$0.002Developer Utilities
Memory retention after days
exponential forgetting curve calculator
POST /edu/memory-retention-after$0.002Developer Utilities
Normalized test score calculator
min-max scale for fair comparison
POST /edu/normalized-test-score$0.002