Ohmly vs Resistor Color Code Calc +
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Ohmly
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Your electrical toolkit, redesigned for speed. 26 pro tools, one clean app. Ohmly is the modern electrical calculator for electricians, students, and engineers. Solve VIRP calculations, decode resistor and SMD codes, check voltage drop, size conductors, design circuits, and keep your work organized—without ads. 26 PRO TOOLS • Ohm's law, resistor color code, SMD resistor code • Series/parallel resistance, voltage divider, LED resistor • Reactance, resonance, AC impedance, power factor • RC/RL/LC filters, decibels, op-amp gain, 555 timer • Voltage drop, wire gauge/AWG, three-phase power • Motor FLA, conduit fill, short-circuit current • Transformer ratio, LM317 regulator • Capacitor code, inductor color code, PCB trace width • Heat sink thermal resistance and battery life WHY OHMLY • Clean light and dark modes with no ads • Shared display metrics across every tool • Save, label, and search calculations • Export multi-calculation PDF reports • Home Screen, Lock Screen, and StandBy widgets • Full Apple Watch companion Unlock Pro with a lifetime purchase or a low monthly plan. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Resistor Color Code Calc +
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Resistor Color Code Calc reads resistor color bands both ways: pick the colors you see, or type a value and see the bands. It checks the reading from both ends of the part, shows which E-series the value belongs to, and reads SMD, capacitor and inductor codes too. ▶ COLORS TO VALUE AND BACK Choose 3, 4, 5 or 6 bands and tap each band to set its color. Every color chip shows its name and what it means in that position (digit, multiplier, tolerance or temperature coefficient), so you do not have to tell shades apart by eye alone. Type a value such as 4.7k, 4k7, 4,7 kΩ, 1M2 or 0R22 and the bands are drawn for you. If the value needs more digits than the chosen band count can show (4.99k on 4 bands), the app says so and offers 5 bands or the closest value with its deviation, instead of rounding silently. ▶ READ CHECK FROM BOTH ENDS Gold, silver and pink cannot be a first digit, black has no tolerance, white has no temperature coefficient. The app checks every band against these position rules from the left and from the right: • only one direction is valid: you get that reading, and Flip turns the bands to match • both directions are valid: both readings are shown side by side, because the colors alone cannot say which end is band 1 • neither direction is valid: the band that breaks the rule is named Gold and silver work as multipliers in the 4th position of 5-band resistors (10 Ω, 1 Ω), and the pink ×0.001 multiplier is supported. ▶ FULL RESULT Value, tolerance range (min – max), temperature coefficient for 6 bands, the working (47 × 10² Ω), the value in plain ohms and RKM code (4K7), and the E-series it belongs to: E3, E6, E12, E24, E48, E96 and E192. If the value is not in the series that fits its tolerance, the nearest values on each side are listed with their deviation. ▶ SMD, CAPACITOR AND INDUCTOR CODES • SMD resistors: 3-digit (472), 4-digit (1002), R notation (4R7, R047) and EIA-96 (01C, 68X) • Capacitors: 3-digit pF codes (104 = 100 nF), last digit 8 or 9 (229 = 2.2 pF), letter as decimal point (4n7, p47) and tolerance letters (J, K, M, Z; B, C and D in pF for small values) • Inductors: 3-digit µH codes (101 = 100 µH) and R/N notation (4R7, 47N) When a code fits more than one marking system, every reading is listed. ▶ BENCH TOOLS • Two values: the closest single standard values and the closest series and parallel pairs from E12, E24 or E96 for the value you need • Voltage divider: R1 and R2 pairs for the output you want • LED resistor: the calculated value, the next E24 value up and the current it gives • Ohm's law: any two of voltage, current, resistance and power Power ratings are suggested with a 2× margin, marked as a rule of thumb. ▶ SAVED Tap Save to keep a reading, a code or a tool result, and reopen a saved band set later. Results saved by the previous version stay in the list. The color code follows IEC 60062 and the series values follow IEC 60063. Printed colors vary between makers and lighting, so confirm critical parts with a multimeter. Works offline, no account. Supported by ads: an ad may appear when you open the app, a banner is shown at the bottom, and a full-screen ad may follow a successful Save. Sharing a result as text can be unlocked for 24 hours by watching an ad.
Screenshots
Verdict
The clearest difference is ads: Ohmly at none against Resistor Color Code Calc +'s shown. Ohmly also leads on device support (3 vs 1). Resistor Color Code Calc +'s advantage is update cadence (every 2 days vs every 3 weeks) and iOS requirement (16.4 vs 26.0). On price and in-app purchases there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Ohmly ships an update every 3 weeks, Resistor Color Code Calc + every 2 days. The most recent releases landed on October 2, 2026 and October 17, 2026 respectively.
| Parameter | Ohmly | Resistor Color Code Calc + |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 3 weeks | Every 2 days — better |
| Ads | No — better | Yes |
| In-app purchases | No | No |
| Devices | iPhone, iPad, Apple Watch — better | iPhone |
| Requires iOS | 26.0 | 16.4 — better |
| Further details — not scored | ||
| Size | 7 MB | 50 MB |
| Age rating | 4+ | 17+ |
| Developer | Adam Wilkie | heekyung moon |
In-app purchases
Ohmly
No in-app purchases
Resistor Color Code Calc +
No in-app purchases
Questions
Is Ohmly free?
Is Resistor Color Code Calc + free?
Do Ohmly or Resistor Color Code Calc + have ads?
Which is updated more often, Ohmly or Resistor Color Code Calc +?
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