Comparison

iSmith vs RF calculator & Smith Chart

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

iSmith

This app helps users understand impedance matching principles. It allows for reading key network parameters from a Smith chart and calculating various matching networks and pads. Users can also convert between different power and voltage units.

Highlights
  • Read Smith chart parameters (Z, Y, VSWR, Q, Gamma)
  • Calculate 8 L-matching networks
  • Calculate T & Pi matching pads
  • Set matching targets on Smith chart
  • Learn impedance matching principles
  • dBm, Watts, and Volts conversion
  • VSWR conversion
Features
Read full description

Features: - Read out Z, Y, VSWR, Q and Gamma from smith chart. - Calculate 8 L-matching networks. - Set matching target by touching smith chart. - Calculate T & Pi matching pad. - Learn the principle of impedance matching. - dBm, Watts and Volts conversion - VSWR Conversion

About

RF calculator & Smith Chart

Features
Read full description

RF Calculator & Smith Chart is an all-in-one RF engineering toolkit for impedance matching, RF network analysis, antenna calculations, filters, attenuators and wireless system design. Built for RF engineers, electronics engineers, students, technicians and radio enthusiasts, it brings essential RF calculations and design tools together in one convenient app. Analyze impedance, work with Smith Charts, calculate VSWR and S11, design matching networks, estimate path loss, build RF attenuators and evaluate wireless links without jumping between multiple tools. RF & IMPEDANCE TOOLS • Smith Chart for impedance visualization and matching • S11 and reflection analysis • Reflection coefficient calculator • VSWR calculator • Impedance and transmission-line calculations • Cascaded RF network calculations IMPEDANCE MATCHING Design and analyze common RF matching networks: • L matching networks • Pi (π) matching networks • T matching networks • Stub tuner calculations Useful for antenna matching, RF amplifiers, transmission lines and other impedance-matching applications. RF FILTER DESIGN Calculate and design common passive and RF filters: • RC filters • RL filters • RLC networks • Butterworth LC low-pass filters • Chebyshev LC low-pass filters • Filter designs up to 8th order • Microstrip band-pass filters • Microstrip band-reject / notch filters RLC CIRCUITS Analyze frequency-dependent RLC networks: • Series RLC circuits • Parallel RLC circuits • Resonant frequency calculations • Frequency behavior and reactance RF ATTENUATOR DESIGN Quickly calculate standard RF attenuator networks: • Pi (π) attenuator • T attenuator • Bridged-T attenuator Ideal for RF signal-level control, impedance-matched pads and test setups. ANTENNA & PROPAGATION TOOLS Plan and evaluate RF and wireless systems with: • Antenna design utilities • Free-space path loss calculations • Friis transmission calculations • RF link budget calculator • Power density calculator • Radar maximum-range calculator COMPONENT DESIGN & REFERENCE Useful electronics tools are also included for RF design and prototyping: • Air-core inductor design • Spiral inductor design • Multi-layer air-core inductor calculations • SMD resistor code • Resistor color code • Resistors in series and parallel • SMD capacitor code • Capacitors in series and parallel BUILT FOR PRACTICAL RF WORK RF Calculator & Smith Chart is designed for quick engineering workflows. Select a tool, enter your parameters and get the values you need without working through repetitive equations manually. Use it for: • RF circuit design • Impedance matching • Antenna projects • Wireless link planning • Filter design • RF testing and troubleshooting • Electronics laboratories • Engineering study and coursework • Amateur radio and RF experimentation Whether you're checking VSWR, designing an impedance-matching network, calculating a link budget or experimenting with RF filters, RF Calculator & Smith Chart keeps essential RF engineering tools within easy reach.

Screenshots

iSmith4 screens
RF calculator & Smith Chart4 screens

Verdict

The call

The clearest difference is in-app purchases: iSmith at none against RF calculator & Smith Chart's 1. iSmith also leads on update cadence (every 2 days vs every 4 months). RF calculator & Smith Chart's advantage is ads (none vs shown). On price, device support and iOS requirement 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. RF calculator & Smith Chart sells 1 one-off in-app purchase. iSmith asks for nothing beyond the download.

UpkeepUpdate frequency

iSmith ships an update every 2 days, RF calculator & Smith Chart every 4 months. The most recent releases landed on October 8, 2026 and October 13, 2026 respectively.

Scorecard3 real differences · 6 level
iSmith versus RF calculator & Smith Chart: the parameters behind the verdict, then further details
ParameteriSmithRF calculator & Smith Chart
PriceFreeFree
Rating5.0 (1 ratings) — better—
Number of ratings1 — better—
Update frequencyEvery 2 days — betterEvery 4 months
AdsYesNo — better
In-app purchasesNo — betterYes
MonetizationAd-supported—
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS16.015.0 — better
Further details — not scored
Size7 MB31 MB
Age rating4+4+
DeveloperRyoun Chon ShinAnas Abubakar

In-app purchases

None

iSmith

No in-app purchases

1 purchases

RF calculator & Smith Chart

One-time1
  • upgrade to pro$3.99

Questions

Is iSmith free?
iSmith is free to download, with no in-app purchases.
Is RF calculator & Smith Chart free?
RF calculator & Smith Chart is free to download, with in-app purchases available.
Do iSmith or RF calculator & Smith Chart have ads?
iSmith shows ads; RF calculator & Smith Chart does not.
Which is updated more often, iSmith or RF calculator & Smith Chart?
iSmith ships an update every 2 days, and RF calculator & Smith Chart every 4 months. Most recently, iSmith was updated on October 8, 2026 and RF calculator & Smith Chart on October 13, 2026.

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