PrefixPlus vs CarKeeper
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
PrefixPlus
Easily add international or custom prefixes to all your phone numbers in contacts simultaneously. This utility helps manage multiple contact entries for different calling regions without overwriting existing numbers. Ensure you back up your contacts before use.
- Add prefixes to multiple contacts at once
- Does not overwrite existing numbers
- Customizable prefix numbers
- Customizable label for new entries
- Supports iCloud and Gmail synchronized contacts
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PrefixPlus allows you to add the prefix number to phone numbers in Contacts at once. Phone numbers with the prefix number will not be replaced but added to contacts. For example, if you set the number "+81" and the label "Call(JP)", contacts will be updated as follows. [Before update] Home: 03-1234-5678 Mobile: 090-1234-5678 [After update] Home: 03-1234-5678 Mobile: 090-1234-5678 Call(JP) Home: +81-3-1234-5678 Call(JP) Mobile: +81-90-1234-5678 (Caution) Be sure to back up contacts as security against accidents. For example, if you back up to iCloud, you can restore contacts at some point in the past. Please note that you can add prefix numbers to contacts synchronized with local, iCloud, Gmail only.
CarKeeper
Manage your vehicle's maintenance and expenses with this smart car housekeeper. Track service history, fuel consumption, and important dates. Keep your car running smoothly and efficiently.
- Vehicle maintenance tracking
- Expense logging
- Service history
- Fuel consumption monitoring
- Important date reminders
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Smart car housekeeper platform.
Screenshots
Verdict
The clearest difference is review sentiment: PrefixPlus at 72% against CarKeeper's 13%. PrefixPlus also leads on rating (4.7 vs 2.9) and ratings volume (1.1K vs 11). CarKeeper's advantage is ads (none vs shown) and monetization model (free vs ad-supported). On price, update cadence, in-app purchases 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
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
PrefixPlus holds the better App Store score, 4.7 against 2.9. That said, the two scores are not equally well evidenced: PrefixPlus has 1.1K ratings behind it against 11, so its average is the more settled of the two. Written reviews point the same way: 72% of PrefixPlus's written reviews are positive against 13% of CarKeeper's.
Both ship on a similar rhythm, roughly every 2 months. Both last shipped on October 24, 2026.
| Parameter | PrefixPlus | CarKeeper |
|---|---|---|
| Price | Free | Free |
| Rating | 4.7 (1.1K ratings) — better | 2.9 (11 ratings) |
| Positive reviews | 71.8% of reviews — better | 12.7% of reviews |
| Number of ratings | 1.1K — better | 11 |
| Update frequency | Every 2 months | Every 2 months |
| Ads | Yes | No — better |
| In-app purchases | No | No |
| Monetization | Ad-supported | Free — better |
| Devices | iPhone, iPod | iPhone, iPod |
| Requires iOS | 15.6 | 9.0 — better |
| Further details — not scored | ||
| Size | 8 MB | 54 MB |
| Age rating | 4+ | 4+ |
| Developer | yasuhiko nagahara | 清贤 高 |
Customer experience
PrefixPlus
CarKeeper
Bugs and requests
PrefixPlus
Reported bugs
3 issues- Crashes on iOS 13.3
- Duplicate contact entries created
- Prefix not applied to all contacts
Requested features
3 requests- Option to add space between prefix and number
- Support for local/offline contacts
- Ability to selectively update contacts
CarKeeper
Not enough reviews yet to summarise bugs or requests.
In-app purchases
PrefixPlus
No in-app purchases
CarKeeper
No in-app purchases
Questions
Is PrefixPlus free?
Is CarKeeper free?
Which has better reviews, PrefixPlus or CarKeeper?
Do PrefixPlus or CarKeeper have ads?
Which is updated more often, PrefixPlus or CarKeeper?
Other comparisons
