Comparison

AIMS ENGINEER vs StandbyCalc

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

Head to head

UK alarm battery sizing tool

Free

🔧 Utilities

No ratingsView app →

About

AIMS ENGINEER

Features

Read full description

Engineer APP for AiMS version 5

About

StandbyCalc

Features

Read full description

StandbyCalc is the fastest way to calculate standby battery requirements for UK fire and intruder alarm systems. Built for engineers, by engineers. Enter your quiescent and alarm currents, select your system grade or category, and get an instant answer — including which standard battery size you need. SUPPORTS: - Intruder alarms — BS EN 50131 / BS 9263, Grades 1-4 - Fire alarms — BS 5839-1:2025, Categories L, M, and P - Standalone PSUs — custom standby and alarm periods FREE FEATURES: - All battery calculations - All standards and grades - Save unlimited calculations - Standard battery size recommendations PRO UPGRADE (one-time purchase): - iCloud backup across devices - PDF reports with full formula working - Add your company logo and branding - Share reports via email, AirDrop, or Files - Professional compliance documentation Compliant with NSI and SSAIB requirements. Calculations per BS 9263 Annex C and BS 5839-1:2025 Annexe E. No account required. No subscription. Just open and calculate.

Screenshots

AIMS ENGINEER4 screens

StandbyCalc4 screens

Verdict

The call

The clearest difference is in-app purchases: AIMS ENGINEER at none against StandbyCalc's 1. AIMS ENGINEER also leads on ads (none vs shown) and update cadence (weekly vs every 4 months). On price and device support 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. StandbyCalc sells 1 one-off in-app purchase. AIMS ENGINEER asks for nothing beyond the download.

UpkeepUpdate frequency

AIMS ENGINEER ships an update weekly, StandbyCalc every 4 months. The most recent releases landed on October 4, 2026 and September 30, 2026 respectively.

Scorecard4 real differences · 2 level

AIMS ENGINEER versus StandbyCalc: the parameters behind the verdict, then further details
Parameter	AIMS ENGINEER	StandbyCalc
Price	Free	Free
Update frequency	Weekly — better	Every 4 months
Ads	No — better	Yes
In-app purchases	No — better	Yes
Devices	iPhone, iPad, iPod — better	iPhone, iPad
Requires iOS	14.0 — better	17.0
Further details — not scored
Size	31 MB	4 MB
Age rating	17+	4+
Developer	Zhimeng Huang	D4N LTD

In-app purchases

None

AIMS ENGINEER

No in-app purchases

1 purchases

StandbyCalc

One-time1

StandbyCalc Pro$9.99

Questions

Is AIMS ENGINEER free?

AIMS ENGINEER is free to download, with no in-app purchases.

Is StandbyCalc free?

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

Do AIMS ENGINEER or StandbyCalc have ads?

StandbyCalc shows ads; AIMS ENGINEER does not.

Which is updated more often, AIMS ENGINEER or StandbyCalc?

AIMS ENGINEER ships an update weekly, and StandbyCalc every 4 months. Most recently, AIMS ENGINEER was updated on October 4, 2026 and StandbyCalc on September 30, 2026.