Embedded Calculators & Part Finder
Size a value with 64 free calculators, then find the real component that fits — in stock, at the best price. For MCU, power, RF & firmware. No account.
★ Popular
💡LED Resistor
⚡Ohm's Law
🚌CAN Bit Timing
🔻Voltage Divider
🔠Glyph Mapper
📦Struct Padding
PWM / Timer
Frequency, period, duty cycle
UART Baud Rate
Error rate, PASS/FAIL check
ADC Resolution
LSB voltage, SNR, dynamic range
Watchdog Timer
STM32 IWDG & WWDG timeouts
I2C Timing
Bus timing & pull-up values
CAN Bus Bit Timing
STM32 bxCAN/FDCAN & MCP2515
SPI Timing
Bit period, frame, throughput
RS-485 Bus
Cable length, termination, bias
LIN Bus Timing
Bit, break, frame time
Modbus RTU Timing
Char & inter-frame gaps
Ring Buffer / DMA
Buffer sizing
Register Map → C
Bitfield struct & macros
CRC → C Code
Lookup table & function
Stepper Motor
Steps/rev, microstep, pulse rate
BLDC / PMSM Speed
Motor electrical freq, pole pairs
Rotary Encoder
Motor encoder counts/rev
Motor Torque ↔ Power
N·m, RPM, Watts, hp
MOSFET Power Loss
Conduction & switching loss
Transformer Turns
Ratio, Ns, current ratio
LDO Dropout / Power
Heat dissipation & efficiency
I2S Audio Clock
BCLK, LRCLK, bit period
USB Data Lines
Bit time, 90Ω, termination
Ethernet Cable
Bit time, delay, 100m limit
Bit Field Visualizer
32-bit register breakdown
Q-Format Converter
Float ↔ fixed-point
Number Base Converter
Dec, Hex, Bin, Oct converter
IEEE 754 Visualizer
32-bit Float & 64-bit Double
Endian Swap
Big/Little/Mid-Endian byte swap
Struct Alignment
C struct padding & visualizer
Memory & Transmission
Bytes, baud rate & sample times
Glyph Mapper
7-Segment & Character LCD custom font generator
Crystal Load Cap
Oscillator load capacitor sizing
Ohm's Law
V, I, R, P — any 2 → all 4
Voltage Divider
Vout, loaded divider, Thevenin
LED Resistor
Series/parallel configs & E24
Resistor Code
Color bands & SMD decoder
Op-Amp Gain
Amp configurations & Schmitt
Instrumentation Amp
3-op-amp in-amp gain & Vout
Op-Amp Resistor
Inverting/Non-inv → R2,R3,R4
BJT Bias CE
Q-point & stability factor
NE555 Timer
Astable / monostable
Capacitor Charge
RC time constant, τ milestones
Buck / Boost
Switching regulator design
AWG Wire Gauge
Wire gauge & voltage drop
Series / Parallel
R · C · L equivalent value
LM317 Regulator
Adjustable Vout & R2 solver
Current Divider
Branch currents in parallel R
LC Resonance
LCR resonant freq, Q-factor
RC Filter
Cutoff frequency, gain & phase
dB Converter
dB, dBm & mW bidirectional
CRC Calculator
CRC-8/16/32, 7 polynomials
Checksum / CRC
XOR, Sum8/16, LRC, CRC
PCB Trace Calc
IPC impedance & trace width
Active Filter
Sallen-Key 2nd-order LPF/HPF
RF Trans. Line
Microstrip impedance (IPC-2141)
VSWR / Return Loss
Γ, return & mismatch loss
RF Link Budget
FSPL, Rx power, margin
Wavelength / Antenna
λ, λ/2 dipole, λ/4 whip
Attenuator Pad
T / Pi resistor values (dB)
Coil Inductance
Air-core solenoid (Wheeler)
Battery Life
Estimated system run-time
Temperature
Units & RTD sensor temps
Wheatstone Bridge
Bridge Vout & balance
Junction Temp
Thermal Tj & max power
Battery Life Calculator
Calculate estimated battery run-time based on current draw, system efficiency, and battery count.
Input Parameters
Results
Calculated Runtime—
Runtime in Days—
Runtime at 80% Capacity—
Self-Discharge (after 6 mo)—
Average Current (I_avg)—
💡 Usage & Formula
Battery Life Estimation projects the operating lifetime of an embedded system, factoring in battery configuration and circuit efficiency.
Formulas:
- Parallel Capacity:
Total_Capacity = Single_Capacity * N_Parallel - Estimated Runtime (hours):
Total_Capacity * (Efficiency / 100) / Load_Current - Self-Discharge:
Capacity_Remaining = Initial * (1 - Rate_per_Month)^Months - Avg Current (duty):
I_avg = Σ (t_k / Σt) × I_k - Modes: Simple (single I), Advanced (Sleep/Active), Most Advanced (Sleep/Collect/Process/Transmit)
Usage: Input battery capacity, average load current, regulator efficiency, and parallel count to estimate operational life.
When you need it: Estimating how long a battery lasts from its capacity and the load's average current, including derating for high-drain loads and duty-cycled MCUs.
Worked example: A 2000 mAh pack at a 50 mA average draw lasts 2000 / 50 = 40 h in the ideal case. Real runtime is capacity × derate / I_avg, so include sleep current in the average.
Tips & gotchas:
- Use a true duty-weighted average current — a device that sleeps 99% of the time is dominated by sleep draw.
- Peukert's law cuts effective capacity as discharge rate rises; a "2000 mAh" cell delivers less at high current.
- Cold temperature and end-of-life ageing both reduce usable capacity — budget margin.
- For long standby, self-discharge and the regulator's quiescent current can exceed the load itself.
📖 References:
Peukert's law (Wikipedia)