Free Tools
36 calculators and converters for electronics, IoT, factory maintenance, GST and everyday development work. Each one runs in your browser and explains the formula behind it.
Electronics
555 Timer Astable Calculator
Calculate frequency, period, duty cycle and high/low times for a 555 timer in astable mode from R1, R2 and C, or check a design before building it.
Open toolAWG Wire Gauge to mm² Calculator
Convert American Wire Gauge (AWG) to diameter and mm² cross-section, or find the AWG nearest a metric size, with copper resistance per metre.
Open toolBattery Life Calculator for IoT Devices
Estimate battery life for a sensor that wakes, transmits and sleeps. Enter capacity, active and sleep current and the wake-up interval.
Open toolCapacitor Code Calculator (104, 223, 4R7)
Decode three-digit ceramic capacitor codes such as 104, 472 or 4R7 into pF, nF and µF, including the tolerance letter (J, K, M).
Open toolLED Resistor Calculator
Find the series resistor for one LED or a string of LEDs from supply voltage, forward voltage and current, with the nearest E12 value and its wattage.
Open toolOhm's Law Calculator: Voltage, Current, Resistance
Enter any two of voltage, current, resistance or power and get the other two. Accepts values like 4.7k, 20m or 3.3 with SI prefixes.
Open toolPCB Trace Width Calculator (IPC-2221)
Calculate the minimum PCB trace width for a given current, copper weight and allowed temperature rise, for internal and external layers.
Open toolRC Time Constant Calculator
Get the RC time constant τ, charge times to 63% and 99%, and the −3 dB cutoff frequency of an RC low-pass filter from R and C values.
Open toolResistor Color Code Calculator (4, 5 & 6 Band)
Pick the band colours on a 4, 5 or 6-band resistor and get its resistance, tolerance range and temperature coefficient instantly.
Open toolResistor Power Rating Calculator
Find how many watts a resistor dissipates from its voltage or current, and the standard wattage rating to buy with a 2× safety margin.
Open toolSeries and Parallel Resistor Calculator
Add up any number of resistors in series or parallel. Paste values like 100, 2.2k, 4.7k and get the total resistance for both arrangements.
Open toolVoltage Divider Calculator
Calculate the output of a two-resistor voltage divider, or find R2 for a target voltage. Shows divider current and power in each resistor.
Open toolIoT & Embedded
ADC Resolution and Voltage Calculator
Find an ADC's step size (LSB) from bit depth and reference voltage, and convert raw ADC readings to volts, or volts to the expected code.
Open toolData Size and Transfer Time Calculator
Convert between bits, bytes, KB, MB, GB, KiB and MiB, and estimate how long a file or firmware update takes over a given link speed.
Open tooldBm to mW Converter (and Watts, dBW)
Convert RF power between dBm, milliwatts, watts and dBW. Useful for radio modules, Wi-Fi, LoRa and link budgets.
Open toolLoRa Airtime Calculator
Calculate LoRa time on air from spreading factor, bandwidth, coding rate and payload, plus how many messages per hour fit a 1% duty cycle.
Open toolMQTT Data Usage Calculator
Estimate how much mobile or SIM data an MQTT device uses per day and month from payload size, topic length, QoS and publish interval.
Open toolPoE Power Budget Calculator
Add up PoE camera, access point and sensor loads, compare them with your switch's PoE budget, and check each device against 802.3af/at/bt limits.
Open toolSampling Rate Calculator (Nyquist)
Find the minimum and recommended sampling rate for a signal, plus the raw data rate for your bit depth and number of channels.
Open toolUART Baud Rate Error Calculator
Check UART baud rate error for a microcontroller clock: get the divider value, the actual baud rate and the % error in normal and double-speed modes.
Open toolIndustrial & Maintenance
Machine Utilization Calculator
Calculate machine utilisation from available shift hours and measured run time, with idle hours and the extra output if you raised it to a target.
Open toolMotor Torque, Power and RPM Calculator
Convert between motor power (kW or HP), speed in RPM and shaft torque in N·m. Enter any two to get the third for gearboxes, pumps and conveyors.
Open toolMTBF and MTTR Calculator with Availability
Calculate mean time between failures, mean time to repair, inherent availability, failure rate and the chance of running a given time without failure.
Open toolOEE Calculator (Availability × Performance × Quality)
Calculate Overall Equipment Effectiveness from planned time, downtime, ideal cycle time and part counts, with the availability, performance and quality split.
Open toolThree-Phase Power Calculator (kW, kVA, Amps)
Calculate three-phase real power, apparent power and reactive power from line voltage, current and power factor, or the current a load will draw.
Open toolVibration Unit Converter (g, mm/s, µm)
Convert sinusoidal vibration between acceleration (g, m/s²), velocity (mm/s) and displacement (µm), in peak, RMS or peak-to-peak, at any frequency.
Open toolBusiness & Finance
CAGR Calculator (Compound Annual Growth Rate)
Calculate compound annual growth rate between a starting and ending value, for revenue, investments or production output, with the total growth.
Open toolCompound Interest Calculator
See how a deposit grows with compound interest at yearly, half-yearly, quarterly or monthly compounding, and the effective annual rate.
Open toolEMI Calculator for Loans
Calculate the monthly EMI, total interest and total repayment for a home, car, business or equipment loan, with a year-by-year breakdown.
Open toolGST Calculator India (Add or Remove GST)
Add GST to a price or extract it from a GST-inclusive amount at any rate, with the CGST + SGST split for intra-state sales or IGST for inter-state.
Open toolProfit Margin and Markup Calculator
Calculate profit, margin and markup from cost and selling price, or find the selling price that gives the margin you want.
Open toolROI and Payback Period Calculator
Work out the payback period and return on investment for equipment, automation or IoT projects from upfront cost and monthly savings.
Open toolDeveloper
Base64 Encode and Decode Online
Encode text to Base64 or decode Base64 back to text, with full UTF-8 support and a URL-safe option. Runs locally, so data never leaves your browser.
Open toolColor Converter: HEX, RGB, HSL and Contrast
Convert colours between HEX, RGB and HSL, preview them, and check WCAG contrast against white and black text for accessible UI and dashboards.
Open toolJSON Formatter and Validator
Format, validate and minify JSON in your browser. Pinpoints the line and column of syntax errors and can sort keys, handy for API and MQTT payloads.
Open toolUnix Timestamp Converter (Epoch to Date)
Convert Unix epoch timestamps in seconds or milliseconds to UTC, IST and your local time, or turn any date into a timestamp. Shows the current epoch.
Open tool