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
Week number within quarter
calculate from an ISO date
POST /date/week-number-in-quarter$0.002Developer Utilities
Number of weeks in a month
calendar week calculator
POST /date/weeks-in-month$0.002Developer Utilities
Date to .NET ticks converter
exact UTC DateTime ticks
POST /date/date-to-dotnet-ticks$0.002Developer Utilities
Hebrew Year Length Calculator
353 to 385 Days
POST /date/hebrew-year-length$0.002Developer Utilities
Hijri month length calculator
29 or 30 days
POST /date/hijri-month-length$0.002Developer Utilities
Ethiopian to Gregorian date converter
POST /date/ethiopian-to-gregorian$0.002Developer Utilities
Good Friday date calculator
Gregorian calendar
POST /date/good-friday$0.002Developer Utilities
Gregorian to Minguo ROC year and date converter
POST /date/gregorian-to-minguo$0.002Developer Utilities
Cyber Monday date
calculate the Monday after Thanksgiving
POST /date/cyber-monday$0.002Developer Utilities
EU daylight saving end date calculator
last Sunday in October
POST /date/daylight-saving-end-eu$0.002Developer Utilities
Super Bowl Sunday date calculator
second Sunday of February
POST /date/super-bowl-sunday$0.002Developer Utilities
Whit Monday date calculator
the day after Pentecost
POST /date/whit-monday$0.002Developer Utilities
Tabular Day of Ashura date calculator
Hijri to Gregorian
POST /date/ashura-tabular$0.002Developer Utilities
Shavuot date calculator by Gregorian year
POST /date/shavuot-date$0.002Developer Utilities
Gap between two time intervals
UTC duration calculator
POST /date/intervals-gap$0.002Developer Utilities
ISO 8601 duration to seconds converter
POST /date/iso-duration-to-seconds$0.002Developer Utilities
Milestone birthday dates calculator from a birth date
POST /date/milestone-birthday-dates$0.002Developer Utilities
Date of your next round age
30th, 40th, 50th birthday calculator
POST /date/next-round-age-day$0.002Developer Utilities
Time elapsed percentage calculator
ISO datetime interval progress
POST /date/time-progress-percent$0.002Developer Utilities
Convert an ISO datetime to Windows FILETIME
POST /date/iso-to-windows-filetime$0.002Developer Utilities
Military time zone letter
UTC offset to NATO designator
POST /date/military-time-zone-letter$0.002Developer Utilities
Minutes to UTC offset string
format signed minutes as UTC±HH:MM
POST /date/minutes-to-offset$0.002Developer Utilities
Civil Twilight Times Calculator
Approximate Dawn and Dusk in UTC
POST /date/civil-twilight-approx$0.002Developer Utilities
Date as fractional year
convert ISO datetime to decimal year
POST /date/fractional-year$0.002Developer Utilities
Next full moon date calculator
POST /date/next-full-moon$0.002Developer Utilities
Maximum Power Transfer Calculator
Match Load Resistance
POST /elec/max-power-transfer$0.002Developer Utilities
Two-node voltage analysis calculator
solve nodal equations
POST /elec/nodal-analysis-2$0.002Developer Utilities
Series-parallel resistor network calculator
equivalent resistance
POST /elec/resistors-mixed$0.002Developer Utilities
Watt-hours from power and time calculator
POST /elec/watt-hours-power-time$0.002Developer Utilities
NTC thermistor temperature from resistance calculator
beta model
POST /elec/ntc-thermistor-temp$0.002Developer Utilities
Six-band resistor color code calculator with temperature coefficient
POST /elec/resistor-color-6band$0.002Developer Utilities
RC Discharging Voltage at Time Calculator
POST /elec/rc-discharge-voltage$0.002Developer Utilities
Supercapacitor backup time calculator
estimate load runtime
POST /elec/supercap-backup-time$0.002Developer Utilities
Coupled inductors in series calculator
aiding and opposing
POST /elec/coupled-inductors-series$0.002Developer Utilities
Parallel plate capacitor area calculator
size plates from capacitance
POST /elec/parallel-plate-area$0.002Developer Utilities
Toroid inductance calculator
L = μ₀μᵣN²A/l
POST /elec/toroid-inductance$0.002Developer Utilities
AC form factor and crest factor calculator
RMS, average and peak
POST /elec/form-crest-factor$0.002Developer Utilities
Impedance polar to rectangular converter
resistance and reactance
POST /elec/impedance-polar-rect$0.002Developer Utilities
Three-phase power calculator
watts from voltage, current and PF
POST /elec/three-phase-power$0.002Developer Utilities
Peak voltage from RMS calculator for sine waves
POST /elec/vpeak-from-vrms$0.002Developer Utilities
Series diode voltage drop calculator
total drop and load voltage
POST /elec/diode-voltage-drop$0.002Developer Utilities
LED resistor by color calculator
red, green, blue, yellow and white
POST /elec/led-resistor-by-color$0.002Developer Utilities
Common Emitter Voltage Gain Calculator
POST /elec/common-emitter-gain$0.002Developer Utilities
MOSFET Drain Current in Saturation Calculator
POST /elec/mosfet-drain-current$0.002Developer Utilities
Rectifier peak inverse voltage calculator
diode PIV rating
POST /elec/rectifier-piv$0.002Developer Utilities
BCD to binary converter
decode packed 8421 BCD
POST /elec/bcd-to-binary$0.002Developer Utilities
Binary division calculator
quotient, remainder and restoring steps
POST /elec/binary-division$0.002Developer Utilities
Ratio to gain dB calculator
voltage and power conversion
POST /elec/ratio-to-gain-db$0.002Developer Utilities
Binary Counter Maximum Count Calculator
States and Modulus
POST /elec/counter-max-count$0.002Developer Utilities
Binary decoder outputs calculator
address lines and range
POST /elec/decoder-outputs$0.002Developer Utilities
Bit Rotate Calculator
Circular Left and Right Rotation
POST /elec/rotate-bits$0.002Developer Utilities
Buck-boost converter duty cycle calculator
inverting supply
POST /elec/buckboost-duty$0.002Developer Utilities
Charge pump voltage calculator
ideal multiplier output
POST /elec/charge-pump$0.002Developer Utilities
Clock frequency and period calculator
frequency, period, and cycles
POST /elec/clock-period$0.002Developer Utilities
555 astable resistor and capacitor calculator
POST /elec/ne555-astable-components$0.002Developer Utilities
Peukert Battery Capacity Calculator for Lead-Acid Batteries
POST /elec/peukert-capacity$0.002Developer Utilities
Solar array energy sizing calculator
required panel wattage
POST /elec/solar-array-sizing$0.002Developer Utilities
Junction temperature calculator
power, ambient and thermal resistance
POST /elec/junction-temperature$0.002Developer Utilities
Parallel conductor ampacity calculator
combined current capacity
POST /elec/parallel-conductors$0.002Developer Utilities
Resistive attenuator pad calculator
matched pi and tee resistor values
POST /elec/resistive-attenuator$0.002