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
How big will my cat get
kitten adult weight calculator
POST /bio/how-big-will-my-cat-get$0.002Developer Utilities
Omega-3 for dogs
daily milligram dose from weight
POST /bio/omega-3-for-dogs$0.002Developer Utilities
Plant population calculator
plants from field area and spacing
POST /bio/plant-population$0.002Developer Utilities
Protein concentration calculator
mg/mL from absorbance curve
POST /bio/protein-concentration$0.002Developer Utilities
qPCR efficiency calculator
percent from standard-curve slope
POST /bio/qpcr-efficiency$0.002Developer Utilities
Rabbit gestation calculator
breeding date to expected kindling
POST /bio/rabbit-gestation$0.002Developer Utilities
Sod calculator
lawn area, rolls and pallets minus obstacles
POST /bio/sod$0.002Developer Utilities
Cost of owning a dog calculator
lifetime total and annual cost
POST /bio/the-cost-of-owning-a-dog$0.002Developer Utilities
Tree diameter calculator
DBH from circumference at breast height
POST /bio/tree-diameter$0.002Developer Utilities
Tree value calculator
appraised value from area, species, condition
POST /bio/tree-value$0.002Developer Utilities
Vegetable yield calculator
harvest weight from bed area, free
POST /bio/vegetable-yield$0.002Developer Utilities
Wastewater BOD removal efficiency calculator
influent vs effluent
POST /bio/wastewater$0.002Developer Utilities
AI water footprint calculator
liters from queries × L/query
POST /eco/ai-water-footprint$0.002Developer Utilities
Carrying capacity calculator
max sustainable population
POST /eco/carrying-capacity$0.002Developer Utilities
COVID lockdown pollution calculator
avoided mass from VKM
POST /eco/covid-pollution$0.002Developer Utilities
Eco-friendly bags
plastic vs paper vs reusable impact
POST /eco/eco-friendly-bags$0.002Developer Utilities
Global plastic policy calculator
reduced tonnes per year
POST /eco/global-plastic-policy$0.002Developer Utilities
Kaya identity calculator
CO2 from population, GDP, energy, carbon
POST /eco/kaya-identity$0.002Developer Utilities
Meat carbon footprint calculator
yearly kg CO2 from diet
POST /eco/meat-footprint$0.002Developer Utilities
Passive house heating savings
annual kWh from area, climate, insulation
POST /eco/passive-house$0.002Developer Utilities
Reduce your plastic
annual kg saved from weekly single-use swaps
POST /eco/reduce-your-plastic$0.002Developer Utilities
Tap water calculator
daily & yearly liters from L/min
POST /eco/tap-water$0.002Developer Utilities
Tree benefits calculator
yearly CO2 absorbed and oxygen
POST /eco/tree-benefits$0.002Developer Utilities
Wind turbine energy calculator
watts and annual kWh from rotor, wind
POST /eco/wind-turbine$0.002Developer Utilities
Attrition rate calculator
percent of employees who left
POST /fin/attrition-rate$0.002Developer Utilities
AVC calculator
cost per unit from TVC and Q, free
POST /fin/avc$0.002Developer Utilities
Basis point converter
bps to percent and decimal, free
POST /fin/basis-point$0.002Developer Utilities
Stock beta calculator
β from stock vs market returns, free
POST /fin/beta-stock$0.002Developer Utilities
Billable hours calculator
invoice total from hourly rate
POST /fin/billable-hours$0.002Developer Utilities
Biweekly mortgage calculator
payoff time and interest saved
POST /fin/biweekly-mortgage$0.002Developer Utilities
Black Friday calculator
sale, coupon, final price & savings
POST /fin/black-friday$0.002Developer Utilities
Boat loan calculator
monthly payment from amount, rate, and term
POST /fin/boat-loan$0.002Developer Utilities
Bradford factor calculator
absence score from spells and days
POST /fin/bradford-factor$0.002Developer Utilities
Build Back Better tax calculator
estimated federal liability
POST /fin/build-back-better$0.002Developer Utilities
Business budget calculator
income, expenses and net
POST /fin/business-budget$0.002Developer Utilities
CAC calculator
cost per customer from spend and acquired, free
POST /fin/cac$0.002Developer Utilities
California stimulus check calculator
estimated MCTR payment
POST /fin/california-stimulus-check$0.002Developer Utilities
UK capital gains tax calculator
tax owed from gain and band
POST /fin/capital-gains-tax-uk$0.002Developer Utilities
Car depreciation calculator
current value from price, rate, and years
POST /fin/car-depreciation$0.002Developer Utilities
Car interest calculator
total interest paid on a car loan
POST /fin/car-interest$0.002Developer Utilities
Carry trade calculator
profit and net return from rates and FX
POST /fin/carry-trade$0.002Developer Utilities
Cash flow to debt calculator
operating cash flow over total debt
POST /fin/cash-flow-to-debt$0.002Developer Utilities
Cash ratio calculator
cash plus equivalents over current liabilities
POST /fin/cash-ratio$0.002Developer Utilities
Child tax credit calculator
CTC from children, status, and AGI
POST /fin/child-tax-credit$0.002Developer Utilities
COGS calculator
cost of goods sold from inventory, free
POST /fin/cogs$0.002Developer Utilities
Mode calculator
find the most frequent value or values
POST /stat/mode$0.002Developer Utilities
Normal distribution calculator
PDF or CDF from mean and σ
POST /stat/normal-distribution$0.002Developer Utilities
Ordering numbers
sort integers, decimals and fractions
POST /stat/ordering-numbers$0.002Developer Utilities
Permutation without repetition
P(n,r)=n!/(n−r)! count
POST /stat/permutation-without-repetition$0.002Developer Utilities
Point estimate calculator
sample mean of a population parameter
POST /stat/point-estimate$0.002Developer Utilities
Three events probability calculator
P(A ∪ B ∪ C)
POST /stat/probability-three-events$0.002Developer Utilities
Range calculator
max minus min of a numeric list
POST /stat/range$0.002Developer Utilities
Relative standard deviation
RSD% = (σ / μ) × 100
POST /stat/relative-standard-deviation$0.002Developer Utilities
Roulette payout calculator
winnings from bet type, stake, and number
POST /stat/roulette-payout$0.002Developer Utilities
Sampling error calculator
signed sample minus population, free
POST /stat/sampling-error$0.002Developer Utilities
Sensitivity and specificity calculator
TPR and TNR, free
POST /stat/sensitivity-and-specificity$0.002Developer Utilities
Simpson's diversity index
probability two random draws differ
POST /stat/simpsons-diversity-index$0.002Developer Utilities
Stem-and-leaf plot calculator
text rows from numeric data
POST /stat/stem-and-leaf-plot$0.002Developer Utilities
Third quartile calculator
Q3, the 75th percentile
POST /stat/third-quartile$0.002Developer Utilities
Two envelopes paradox calculator
switch vs keep EV
POST /stat/two-envelopes-paradox$0.002