Calculators that pick real parts.
Every answer comes back as a standard E-series value with its error, current and power — the numbers you need before ordering. Instant, in your browser, nothing sent anywhere.
Calculators
Vout from Vin and two resistors, or the best standard pairs for a target Vout — with tolerance range and load effect.
Feedback pairs for any Vref, for feedback-pin parts and three-terminal adjustables, with the bias-current term, worst-case range and divider-current guidance.
Any two of V, I, R, P give the other two, plus the nearest standard resistor and a power rating with margin.
The resistor for one or several LEDs in series, rounded up to a standard value, with actual current and power rating.
4, 5 and 6-band colours, 3 and 4-digit SMD marks and EIA-96 codes, both directions.
Inverting or non-inverting: the standard pair closest to a target gain, with the input impedance it implies.
Standard values for two or three resistors in fixed ratios, such as R1:R2 and R1:R3, or for a switchable divider with two attenuations. Ranked by the worst ratio error.
Bipolar to unipolar level shifter: R1, R2 and R3 that map, say, −10…+10 V onto 0.2…4.8 V for an ADC, with the real Vout, currents and source impedance.
Capacity, sleep and active current and wake interval give an estimated run time, with the sleep-vs-awake energy split.
Vref and bit width give the LSB size and counts↔volts both ways, with an optional input divider for battery monitoring.
Decimal, hex, binary, octal and ASCII, live, with a clickable bit grid at 8, 16, 32 or 64 bits and signed two’s-complement.
Trace width for a target impedance, or the impedance of a width: microstrip and stripline, single or differential pair, with 4-layer stack-up presets.
Beta or Steinhart–Hart in; temperature, pin voltage, ADC code and °C per LSB out, with the fixed resistor for your range and the Beta error.
Millivolts to °C and back for eight types, with the cold junction compensated in volts and °C per LSB for your amplifier and ADC.
Worst-case voltage and current against one resistor rating, standard or typed in: the largest and smallest R that survive the fault, from 0201 to 10 W.
Free design checks
Deeper tools that read your actual files and boards, in the browser.
Paste a bill of materials and get a lifecycle and availability verdict per line before you order.
Drop Gerbers, BOM and placement file; see what is missing or inconsistent before you ask for a quote.
Drop a fab .zip or Gerber and drill files and see the board: realistic top and bottom render, layers, size and parts overlay. Drawn in your browser, nothing uploaded.
Board programming
Flash real hardware over USB, straight from the browser.
Flash a .bin over USB from the browser. It reads the chip and the file first and refuses firmware built for a different chip, revision or flash size.
Connect a USB board and read or send serial text and hex from the browser. Baud rate and format, DTR/RTS reset profiles for ESP32 and Arduino, timestamps and a saved log. Nothing leaves your computer.
Flash a .dfu, .hex or .bin over USB DFU from the browser. It reads the chip’s flash map and identity first and refuses firmware whose bytes or vector table do not belong on it. Never touches option bytes.
Need a break?
Trace Rush: route copper to every pad without shorting your own trace.
Play Trace Rush