# ACI DSIM vs Big Clock

The clearest difference is price: ACI DSIM at Free against Big Clock's $1.99. ACI DSIM also leads on device support (3 vs 1) and iOS requirement (11.0 vs 17.0). Big Clock's advantage is update cadence (daily vs every 3 weeks). On ads and in-app purchases there is nothing between them.

ACI DSIM is free to download; Big Clock costs $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ACI DSIM ships an update every 3 weeks, Big Clock daily. The most recent releases landed on November 3, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | ACI DSIM | Big Clock |
| --- | --- | --- |
| Price | **Free** | $1.99 |
| Rating | — | **[5.0 (2 ratings)](https://appshunter.io/ios/app/big-clock-overtime/id6813792770/reviews)** |
| Number of ratings | — | **2** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Daily** |
| Monetization | — | Paid |
| Size | 59 MB | 2 MB |
| Requires iOS | **11.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [ACI Communications, Inc](https://appshunter.io/developer/1141246666) | [DEREK MATTHEW PERRY](https://appshunter.io/developer/6813792772) |

## What reviewers say

### ACI DSIM

[App page](https://appshunter.io/ios/app/aci-dsim/id1550253698)

**Features:** macOS Compatibility

**In-app purchases:** none


### Big Clock

[App page](https://appshunter.io/ios/app/big-clock-overtime/id6813792770)

Track your overtime earnings in real-time with this simple hourly tracker. See your estimated earnings grow by the second, even on your lock screen. Ideal for anyone working by the hour who wants to visualize their extra income.

**Highlights:** Real-time earnings tracking, Customizable overtime multipliers, Lock Screen Live Activity, Big Mode for focused display, Pause and resume clock, Overtime history viewing

**In-app purchases:** none


## Frequently asked questions

### Is ACI DSIM free?

ACI DSIM is free to download, with no in-app purchases.

### Is Big Clock free?

Big Clock costs $1.99, with no in-app purchases.

### Do ACI DSIM or Big Clock have ads?

Neither ACI DSIM nor Big Clock shows ads.

### Which is updated more often, ACI DSIM or Big Clock?

ACI DSIM ships an update every 3 weeks, and Big Clock daily. Most recently, ACI DSIM was updated on November 3, 2026 and Big Clock on October 31, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*