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
Grade-adjusted pace calculator
uphill and downhill running GAP
POST /health/grade-adjusted-pace$0.002Developer Utilities
Heart Rate Recovery Ratio Calculator
POST /health/heart-rate-recovery-ratio$0.002Developer Utilities
Heart rate reserve calculator
maximum minus resting heart rate
POST /health/heart-rate-reserve$0.002Developer Utilities
Robergs-Landwehr maximum heart rate calculator
POST /health/hrmax-robergs$0.002Developer Utilities
Intermittent fasting window calculator
meal and fast times
POST /health/if-eating-window$0.002Developer Utilities
Lactate threshold heart rate estimate
% of max HR free
POST /health/lactate-threshold-hr$0.002Developer Utilities
Macro Split from Calories Calculator
Protein, Carbs and Fat Grams
POST /health/macro-split-from-cal$0.002Developer Utilities
Omega-6 to omega-3 ratio calculator
fatty acid intake in grams, free
POST /health/omega-ratio$0.002Developer Utilities
Lombardi one rep max calculator for weight and repetitions
POST /health/one-rep-max-lombardi$0.002Developer Utilities
Mayhew One-Rep Max Calculator from Weight and Repetitions
POST /health/one-rep-max-mayhew$0.002Developer Utilities
Percent VO2max from heart rate calculator
%HRR to %VO2max linear
POST /health/percent-vo2max-from-hr$0.002Developer Utilities
Equivalent race times calculator
one result across common distances
POST /health/race-equivalent-times$0.002Developer Utilities
Saturated fat limit calculator
daily grams from calories
POST /health/saturated-fat-limit$0.002Developer Utilities
Serum osmolality calculator
sodium, glucose and BUN
POST /health/serum-osmolality$0.002Developer Utilities
Sinclair Meltzer-Faber masters calculator
SMF by weight, age, sex
POST /health/sinclair-masters$0.002Developer Utilities
Swim stroke rate calculator
strokes per minute from count and time
POST /health/swim-stroke-rate$0.002Developer Utilities
Time to sober calculator
estimate hours until BAC reaches zero
POST /health/time-to-sober$0.002Developer Utilities
Cycling variability index calculator
VI = NP / average power, free
POST /health/variability-index$0.002Developer Utilities
Warm-Up Set Weight Calculator
Percentage Loading Scheme
POST /health/warmup-set-weight$0.002Developer Utilities
Water intake per calorie calculator
1 mL per kcal daily needs, free
POST /health/water-from-calories$0.002Developer Utilities
Buy one get one effective price calculator
cost per item
POST /life/bogo-effective-price$0.002Developer Utilities
Cash change due calculator
subtract total from amount tendered
POST /life/change-due$0.002Developer Utilities
Coin jar value calculator
total value for deposit and rolling
POST /life/coin-jar-value$0.002Developer Utilities
Coupon savings calculator
final price and amount saved
POST /life/coupon-savings$0.002Developer Utilities
Group dinner cost share calculator
split shared dishes fairly free
POST /life/dinner-split-by-share$0.002Developer Utilities
Divide money evenly with cents calculator
exact shares
POST /life/divide-money-evenly$0.002Developer Utilities
Gift card and cash split calculator
calculate each payment
POST /life/gift-card-split$0.002Developer Utilities
Itemized bill split calculator
assign items, tax & service free
POST /life/itemized-bill-split$0.002Developer Utilities
Membership break-even calculator
membership vs pay-as-you-go
POST /life/membership-break-even$0.002Developer Utilities
Price ladder tier calculator
generate stepped prices
POST /life/price-ladder$0.002Developer Utilities
Shopping budget tracker
remaining funds after item prices, free
POST /life/shopping-budget$0.002Developer Utilities
Divisibility test
check if one integer is evenly divisible by another
POST /math/divisibility-test$0.002Developer Utilities
Divisor calculator
all positive divisors of an integer, sorted
POST /math/divisor$0.002Developer Utilities
Regular dodecagon
area, perimeter and interior angle from the side length
POST /math/dodecagon$0.002Developer Utilities
Double-angle formula
evaluate sin(2x), cos(2x) or tan(2x) from one angle
POST /math/double-angle-formula$0.002Developer Utilities
Double-angle identities
sin(2x), cos(2x) and tan(2x) from one angle
POST /math/double-angle-identities$0.002Developer Utilities
e^x calculator
exponential of x online, free
POST /math/e-power-x$0.002Developer Utilities
Egyptian fraction calculator
distinct unit fraction expansion, free
POST /math/egyptian-fraction$0.002Developer Utilities
Eigenvalue and eigenvector calculator
any square matrix, free
POST /math/eigenvalue-eigenvector$0.002Developer Utilities
Elimination method
solve a system of two linear equations, free
POST /math/elimination-method$0.002Developer Utilities
Ellipse circumference calculator
Ramanujan approximation from semi-axes
POST /math/ellipse-circumference$0.002Developer Utilities
Ellipse perimeter
Ramanujan approximation from the semi-axes
POST /math/ellipse-perimeter$0.002Developer Utilities
Ellipse standard form
center and semi-axes from the general equation
POST /math/ellipse-standard-form$0.002Developer Utilities
Endpoint calculator
find the missing endpoint from the midpoint
POST /math/endpoint$0.002Developer Utilities
Engineering notation
coefficient and exponent (multiple of 3)
POST /math/engineering-notation$0.002Developer Utilities
Equation of a circle from diameter endpoints
center, radius
POST /math/equation-circle-diameter-endpoints$0.002Developer Utilities
Equation of a plane
from three points or a point and normal vector
POST /math/equation-of-a-plane$0.002Developer Utilities
Equilateral triangle area calculator
area from side length, free
POST /math/equilateral-triangle-area$0.002Developer Utilities
Equivalent fractions calculator
multiply numerator and denominator, free
POST /math/equivalent-fractions$0.002Developer Utilities
Equivalent ratio calculator
scale numerator and denominator free
POST /math/equivalent-ratio$0.002Developer Utilities
Error function calculator
erf(x) between -1 and 1
POST /math/error-function$0.002Developer Utilities
Euclidean algorithm calculator
GCD with every division step
POST /math/euclidean-algorithm$0.002Developer Utilities
Euclidean distance calculator
distance between two vectors, free
POST /math/euclidean-distance$0.002Developer Utilities
Euler's polyhedron formula calculator
V − E + F = 2, free
POST /math/eulers-formula-for-polyhedron$0.002Developer Utilities
Exact value of trig functions
sin cos tan csc sec cot in radicals, free
POST /math/exact-value-of-trig-functions$0.002Developer Utilities
Expanded form calculator
expand a number into place-value terms
POST /math/expanded-form$0.002Developer Utilities
Expanding logarithms
product, quotient and power rules
POST /math/expanding-logarithms$0.002Developer Utilities
Exponent calculator
raise any base to any power
POST /math/exponent$0.002Developer Utilities
Exponential form
write any number as mantissa times ten to a power, free
POST /math/exponential-form$0.002Developer Utilities
Exponential function calculator
evaluate a·b^x
POST /math/exponential-function$0.002