Comparison

RF Engineer's Calc vs Kestrel

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

Head to head

About

RF Engineer's Calc

Features

Read full description

A simple RF Engineer's Calculator. Convert Watts to dBm, calculate dBm power changes, convert Return Loss to VSWR, etc...

About

Kestrel

Features

Read full description

Take total control of your infrastructure from anywhere. Kestrel is a premium, server management client designed for developers, sysadmins, and power users who demand performance, security, and smart features on the go.. Privacy Policy: Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Screenshots

RF Engineer's Calc3 screens

Kestrel4 screens

Verdict

The call

The clearest difference is in-app purchases: RF Engineer's Calc at none against Kestrel's 4. Kestrel's advantage is update cadence (fortnightly vs every 10 months) and device support (3 vs 1). On price, ads 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. Kestrel sells 4 in-app purchases, starting at $3.99 per month. RF Engineer's Calc asks for nothing beyond the download.

UpkeepUpdate frequency

RF Engineer's Calc ships an update every 10 months, Kestrel fortnightly. The most recent releases landed on October 6, 2026 and October 3, 2026 respectively.

Scorecard3 real differences · 3 level

RF Engineer's Calc versus Kestrel: the parameters behind the verdict, then further details
Parameter	RF Engineer's Calc	Kestrel
Price	Free	Free
Update frequency	Every 10 months	Fortnightly — better
Ads	No	No
In-app purchases	No — better	Yes
Devices	iPhone	iPhone, iPad, Mac — better
Requires iOS	16.1 — better	17.0
Further details — not scored
Size	43 MB	37 MB
Age rating	4+	4+
Developer	GRAHAM JOHN SMITH	Michael Wright

In-app purchases

None

RF Engineer's Calc

No in-app purchases

4 purchases

Kestrel

Subscriptions3

Kestrel Pro$3.991 Month
Kestrel Pro Yearly7 Days trial$24.991 Year
Kestrel Suite$39.991 Year

One-time1

Kestrel Pro Lifetime$50.00

Questions

Is RF Engineer's Calc free?

RF Engineer's Calc is free to download, with no in-app purchases.

Is Kestrel free?

Kestrel is free to download, with in-app purchases available.

Do RF Engineer's Calc or Kestrel have ads?

Neither RF Engineer's Calc nor Kestrel shows ads.

Which is updated more often, RF Engineer's Calc or Kestrel?

RF Engineer's Calc ships an update every 10 months, and Kestrel fortnightly. Most recently, RF Engineer's Calc was updated on October 6, 2026 and Kestrel on October 3, 2026.