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
Chord calculator
notes from root and chord type, free
POST /hobby/chord$0.002Developer Utilities
Chord finder
identify a chord from note names, free
POST /hobby/chord-finder$0.002Developer Utilities
Chord inversion calculator
reorder chord notes
POST /hobby/chord-inversion$0.002Developer Utilities
Days Until Christmas Calculator
POST /date/days-until-christmas$0.002Developer Utilities
Container Loading Calculator
How Many Boxes Fit
POST /ecom/container-loading$0.002Developer Utilities
Classroom spacing calculator
max students from room and spacing
POST /edu/classroom-spacing$0.002Developer Utilities
College GPA calculator
credit-hour weighted 4.0 scale
POST /edu/college-gpa$0.002Developer Utilities
Crosstalk calculator
cable interference from signal, distance, coupling
POST /elec/crosstalk$0.002Developer Utilities
Chord transposer
shift chords and progressions by semitones
POST /hobby/chord-transposer$0.002Developer Utilities
Days Until Valentine's Day Calculator
POST /date/days-until-valentines-day$0.002Developer Utilities
Duty cycle calculator
pulse width / period in percent, free
POST /elec/duty-cycle$0.002Developer Utilities
Delay and reverb times calculator
tempo-synced ms, free
POST /hobby/delay-reverb-times$0.002Developer Utilities
Diamond Weight Calculator
Estimate Carats from Dimensions
POST /hobby/diamond-weight$0.002Developer Utilities
Dating theory
half-your-age-plus-seven min and max ages
POST /life/dating-theory$0.002Developer Utilities
DPMO calculator
defects per million opportunities, free
POST /stat/dpmo$0.002Developer Utilities
Grade curve calculator
linear or square-root scaling to a target mean
POST /edu/grade-curve$0.002Developer Utilities
Hamming code calculator
Hamming(7,4) encode four data bits
POST /enc/hamming-code$0.002Developer Utilities
Harmonic series
nth partial sum H_n = 1+1/2+…+1/n
POST /hobby/harmonic-series$0.002Developer Utilities
Hire an expert vs train a fresher
first-year cost
POST /biz/hire-an-expert-vs-train-a-fresher$0.002Developer Utilities
Image file size calculator
bytes and MB from width, height, bits
POST /date/image-file-size$0.002Developer Utilities
Journal impact factor calculator
two-year IF from citations
POST /edu/impact-factor$0.002Developer Utilities
LM317 calculator
output voltage from R1 and R2
POST /elec/lm317$0.002Developer Utilities
Latitude longitude distance
haversine km between two points
POST /geo/latitude-longitude-distance$0.002Developer Utilities
Minecraft stack calculator
items to stacks of 64 or 16
POST /game/minecraft-stack$0.002Developer Utilities
MM to carat conversion
gemstone diameter to carat weight
POST /hobby/mm-to-carat-conversion$0.002Developer Utilities
NaNoWriMo daily word count
words per day to finish
POST /edu/nanowrimo$0.002Developer Utilities
Song duration calculator
BPM, time signature, and measures
POST /hobby/music-duration$0.002Developer Utilities
Music transposer
notes and chord progressions by semitones
POST /hobby/music-transposer$0.002Developer Utilities
Op-amp gain calculator
inverting Av = −Rf/Rin, free
POST /elec/op-amp-gain$0.002Developer Utilities
Odd parity bit calculator
0 or 1 so ones count is odd, free
POST /enc/odd-parity$0.002Developer Utilities
Password entropy calculator
bits of strength from charset size and length
POST /security/password-entropy$0.002Developer Utilities
PCB trace current calculator
max safe amps from width
POST /elec/pcb-trace-current$0.002Developer Utilities
PCB trace width calculator
minimum width in mils
POST /elec/pcb-trace-width$0.002Developer Utilities
Pizza tip calculator
tip, total, and per-person share
POST /life/pizza-tip$0.002Developer Utilities
RAM latency calculator
first-word ns from CAS and MHz
POST /dev/ram-latency$0.002Developer Utilities
RAID calculator
usable capacity and disk fault tolerance
POST /game/raid$0.002Developer Utilities
Rounds per minute calculator
convert per-second or per-hour fire rate
POST /biz/rounds-per-minute$0.002Developer Utilities
Semitone calculator
nearest note and cents from frequency in Hz
POST /hobby/semitone$0.002Developer Utilities
Sandbox calculator
cubic feet of sand and bag count from size
POST /home/sandbox$0.002Developer Utilities
Snowman calculator
snow volume from three ball radii
POST /hobby/snowman$0.002Developer Utilities
Small caps converter
Unicode small-capital letters from lowercase
POST /str/small-caps$0.002Developer Utilities
Test grade calculator
letter grade from score and maximum
POST /edu/test-grade$0.002Developer Utilities
Tip from net price
suggested tip and gross total, free
POST /life/tip-from-net-price$0.002Developer Utilities
Subscript generator
Unicode subscript letters and digits
POST /str/subscript-generator$0.002Developer Utilities
Superscript generator
Unicode tiny raised letters & digits, free
POST /str/superscript-generator$0.002Developer Utilities
Travel job application cost calculator
fees, documents, travel, free
POST /biz/travel-job-application$0.002Developer Utilities
What grade was I in year
US school grade from birth year
POST /edu/what-grade-was-i-in-year$0.002Developer Utilities
Activation energy calculator
Arrhenius Ea from two rates, free
POST /chem/activation-energy$0.002Developer Utilities
Alligation calculator
mix two concentrations to a target, free
POST /chem/alligation$0.002Developer Utilities
Atomic mass calculator
isotope masses and abundances to amu
POST /chem/atomic-mass$0.002Developer Utilities
Avogadro calculator
moles to particles N = n·N_A, free
POST /chem/avogadro$0.002Developer Utilities
Boiling point calculator
Tb = T0 + Kb·m from molality
POST /chem/boiling-point$0.002Developer Utilities
Calibration curve calculator
least-squares slope, intercept and R²
POST /chem/calibration-curve$0.002Developer Utilities
Chemical name from formula
common name for a known compound
POST /chem/chemical-name$0.002Developer Utilities
Combustion reaction calculator
O₂, CO₂ and H₂O from CₓHᵧ
POST /chem/combustion-reaction$0.002Developer Utilities
Crude protein calculator
nitrogen % × conversion factor
POST /chem/crude-protein$0.002Developer Utilities
Hydraulic detention time calculator
τ = V/Q from tank volume and flow
POST /chem/detention-time$0.002Developer Utilities
Effective nuclear charge calculator
Z_eff = Z − S, free
POST /chem/effective-charge$0.002Developer Utilities
Electrolysis calculator
mass deposited or gas evolved, Faraday
POST /chem/electrolysis$0.002Developer Utilities
Witcher monster slayer
hits needed and leftover damage
POST /game/witcher-monster-slayer$0.002