OhmsLab vs VoltKit

The everyday electronics bench in your pocket. Solve Ohm's law, read resistor color codes, and size LED resistors in seconds, all on your iPhone. WHAT IT DOES - Ohm's law and power: enter any two of voltage, current, resistance or power and get the other two - Resistor color decoder: 4, 5 and 6 band, with tolerance and temperature coefficient, drawn on a real resistor - Find the colors for a value: enter a resistance and see the bands - LED series resistor: from supply, forward voltage and current, with the nearest standard value and a power rating - Series and parallel: combine any number of resistors, both totals at once - Voltage divider: output voltage, current and power, plus a helper to size R2 for a target output - Save any calculation to your bench and reopen it live - Bench reference: the full color code table, SI prefixes and the Ohm's law relationships - Copy any result, clean dark bench interface PRIVATE BY DESIGN Everything you enter stays on your iPhone. No account, no cloud, no tracking. FREE AND LIFETIME Free includes the Ohm's law and power solver and the full resistor color decoder, with unlimited saved calculations. The one time Lifetime unlock ($4.99 USD, pay once, no subscription) adds the LED resistor, voltage divider, and series and parallel tools, plus PDF and CSV bench sheet export. Built for makers, students, repair techs, and anyone who keeps a soldering iron warm. A planning aid for hobby and bench work. Check part datasheets and ratings before you build.

VoltKit is the fast, no-nonsense electrical calculator built for the field. VOLTAGE DROP — Single-phase, three-phase and DC. AWG or mm², feet or meters, copper or aluminum. Instant pass/fail against the 3% / 5% guidelines, with the recommended minimum conductor size. WIRE SIZE (Pro) — Enter load, distance and voltage. Get the minimum conductor that satisfies BOTH voltage drop and ampacity, with each constraint shown separately. OHM'S LAW & POWER — Enter any two values, get the rest. Power factor supported for AC. WHY ELECTRICIANS CHOOSE VOLTKIT • 100% offline — no account, no ads, no tracking, no permissions • Shows the math — every result includes the formula with your values plugged in • Built for the field — dark, glove-friendly, instant results as you type • One-time purchase — Pro is yours forever, no subscription COMING IN FREE UPDATES FOR PRO USERS Ampacity with derating, conduit fill, box fill, motor calculations, EV charger circuit sizing. Results are estimates for reference only. Always verify with the current edition of applicable codes and a licensed professional. National Electrical Code® and NEC® are registered trademarks of the National Fire Protection Association, which is not affiliated with this app.