Calculators38 tools
Engineering calculators
The numbers we check on every board and harness. Each calculator names its standard and edition, shows its formula, and warns when an input leaves the range the method covers.
PCB design
- PCB trace width calculatorMinimum trace width for a current and temperature rise, with the resistance, voltage drop and power loss over the run.IPC-2221B
- PCB impedance calculatorCharacteristic and differential impedance for the six common PCB line structures, with effective dielectric constant and propagation delay. Presets use the published JLCPCB and OSH Park 4-layer stackups.Hammerstad and Jensen, IPC-2141, Ghione and Naldi
- Via current calculatorCurrent one plated via carries for a temperature rise, its resistance, and how many vias in parallel a target current needs.IPC-2221B, IPC-6012
- PCB trace resistance calculatorDC resistance of a copper trace at temperature, with the voltage drop and power at a given current.IACS copper, IPC-2221B
- PCB conductor spacing calculator (IPC-2221)Minimum spacing between conductors for a peak voltage, from IPC-2221B Table 6-1, for each layer, altitude and coating condition.IPC-2221B Table 6-1
Wire and harness
- Wire gauge and ampacity calculatorThe smallest AWG or kcmil conductor that carries a load after NEC ambient and conductor-count derating, with the full ampacity table for the chosen column.NEC 2023 310.16, 310.17
- Voltage drop calculatorVoltage drop, load voltage and wire loss for a run, and the smallest wire size that keeps the drop within your target.NEC Ch. 9 Table 8
- Conduit fill calculatorFill percentage, pass or fail and the maximum conductor count for a raceway, from the NEC Chapter 9 tables for each conduit type.NEC Ch. 9 Tables 1, 4, 5
- Wire bundle diameter calculatorThe approximate diameter of a wire bundle from the count and outside diameter of each wire, for choosing a backshell entry, sleeving or heat shrink.Glenair bundle factors
- AWG wire size chartDiameter, cross-section and resistance for any AWG size from 4/0 to 40, with the full chart and your gauge highlighted.ASTM B258, IACS
Embedded and SoC
- I2C pull-up resistor calculatorThe valid pull-up range for an I2C bus from the supply, the mode and the bus capacitance, with a standard value that stays inside it across its tolerance.NXP UM10204 Rev. 7.0
- UART baud rate calculatorThe divisor, actual baud rate and error for a UART clock, and whether the total clock mismatch fits the budget a receiver can tolerate.Maxim AN2141, TI TL16C550D
- Crystal load capacitance calculatorThe two load capacitors that give a crystal its specified load capacitance, or the load an existing pair actually presents, with the closest standard values.Microchip AN826
- DDR length matching calculatorConverts a DQ to DQS skew budget into allowed length mismatch on your routing layer, and checks up to eight DQ nets of a byte lane against their strobe.Delay per length, √Er,eff / c
- MIPI CSI-2 bandwidth calculatorThe bit rate a camera stream needs over MIPI CSI-2, and how many D-PHY data lanes carry it at the per-lane rate you choose.MIPI CSI-2, D-PHY
- PCB propagation delay calculatorDelay per length for stripline and microstrip traces from the dielectric constant, the delay of a given trace, and the length that gives a target delay.TI SCAA082A, √Er,eff / c
Power and reliability
- Battery life calculatorRuntime of a duty-cycled load from active and sleep current, wake interval, self-discharge and the capacity you can actually use, with the remaining charge plotted over time.Microchip AN1416, TI SLVA118A
- LDO power dissipation calculatorPower burned in a linear regulator and the junction temperature it produces, with the highest ambient and output current that keep the junction under its limit.TI SLVA118A, SLVA462
- Buck converter calculatorPower stage values for a step-down converter in continuous conduction: duty cycle, inductance for a ripple target, peak current against the switch limit, output ripple and input capacitor RMS current.TI SLVA477C
- Boost converter calculatorPower stage values for a step-up converter in continuous conduction: duty cycle, inductance for a ripple target, peak and RMS inductor current, the output current the switch limit allows, and output ripple.TI SLVA372D
- MTBF calculatorSeries-system failure rate from up to eight lines of quantity and rate, converted to MTBF, FIT, annualized failure rate and the probability of surviving a mission.MIL-HDBK-217F App. A, exponential
- Heatsink thermal resistance calculatorThe largest heatsink thermal resistance that keeps the junction at its limit, given the power, ambient, the package θJC and the interface material θCS.TI SLVA118A, SLVA462
- Heatsink designer and STEP generatorSize a plate-fin heatsink for a chip, with a fan on top, your own airflow or none, and download a STEP file and drawing that follow JLCPCB's CNC rules. Free, no sign-up.Teertstra 2000, Culham 2001, JLCCNC
Circuit basics
- Ohm's law calculatorEnter any two of voltage, current, resistance and power to get the other two.V = I R, P = I V
- Parallel resistor calculatorSeries and parallel totals for up to six resistors, and the current through each branch when a known current splits between them.Kirchhoff, R∥ = 1 / Σ(1/R)
- Series capacitance calculatorSeries and parallel totals for up to six capacitors, and how an applied voltage divides across a series string.1/Cs = Σ 1/C, Cp = Σ C
- Voltage divider calculatorOutput voltage and source impedance of a divider, the closest standard resistor pair for a target voltage, and feedback values for an adjustable regulator.IEC 60063 E-series, TI SLVS044Z
- LED resistor calculatorResistor value for an LED or a series string, rounded up to a standard value, with the real current and the power rating the resistor needs.Ohm’s law, KOA TN-007
- Resistor color code calculatorValue, tolerance and temperature coefficient from the color bands, or the bands for a value, per the IEC 60062 color code.IEC 60062:2016
- SMD resistor code calculatorResistance from a chip resistor marking in 3 digit, 4 digit or EIA-96 form, with the same value written in the other two formats.EIA-96, IEC 60063 E96
- Capacitor code calculatorCapacitance from a three digit code and tolerance letter, in pF, nF and µF, with the minimum and maximum value.KEMET C1003, IEC 60062
Signals and RF
- dBm to watts calculatorConvert any power or voltage level to every other one across a 50, 75 or 600 Ω load, or turn a dB figure into power and voltage ratios.ITU-R V.574-5
- RC filter calculatorCutoff frequency and time constant of a first-order RC filter, with the attenuation and phase at a frequency you choose and the full magnitude response.TI SLOA049D, first-order RC
- LC filter calculatorResonant frequency, characteristic impedance and Q of a second-order LC low-pass driving a resistive load, with the magnitude response.TI SLOA049D, second-order form
- Reactance calculatorCapacitor and inductor reactance at a frequency, and the impedance and phase of a series RC, RL or RLC circuit.X_C = 1/(2πfC), X_L = 2πfL
- Op amp gain calculatorClosed-loop gain and output voltage for the four basic op amp circuits, with a warning when the output would hit a supply rail.TI SBOA092B, ideal op amp
- 555 timer calculatorFrequency, high and low time and duty cycle of an astable 555, or the pulse width of a monostable one, from the NE555 datasheet equations.TI NE555, SLFS022K
- Wavelength to frequency calculatorFree-space and on-board wavelength for a frequency, or the frequency for a wavelength, with quarter-wave and half-wave lengths and delay per unit length.λ = c / (f · sqrt(εeff))