# VoltTimer vs Stackr

The clearest difference is update cadence: Stackr at every 4 days against VoltTimer's every 3 weeks. Stackr also leads on chart position (#186 vs unranked). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. VoltTimer sells 1 one-off in-app purchase and Stackr sells 7 in-app purchases, starting at $7.99 per 7 days. Whichever you choose, the download price is not the number that matters.

VoltTimer ships an update every 3 weeks, Stackr every 4 days. The most recent releases landed on October 7, 2026 and October 22, 2026 respectively.

## The numbers

| Metric | VoltTimer | Stackr |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[4.4 (184 ratings)](https://appshunter.io/ios/app/stackr-peptide-glp-1-tracker/id6764821587/reviews)** |
| Number of ratings | — | **184** |
| Positive reviews | — | 66.7% of reviews |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Every 4 days** |
| Monetization | — | Freemium |
| Best chart rank | — | **#186** |
| Size | 6 MB | 88 MB |
| Requires iOS | 18.6 | **17.0** |
| Devices | **iPhone, iPad** | iPhone |
| Age rating | 4+ | 12+ |
| Developer | [CherneyWerk LLC](https://appshunter.io/developer/1887149773) | [Stackr Holdings LLC](https://appshunter.io/developer/1896525659) |

## What reviewers say

### VoltTimer

[App page](https://appshunter.io/ios/app/volttimer-workout-timer/id6760988281)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| VoltTimer Pro | $3.99 | one-time |


### Stackr

[App page](https://appshunter.io/ios/app/stackr-peptide-glp-1-tracker/id6764821587)

**Currently charting:** #186 Top Grossing · Health & Fitness (US App Store)

This app simplifies tracking peptide and GLP-1 doses, including supplies like vials and pens. It offers smart reminders, home screen widgets, and visual charts of estimated active levels based on half-life. Designed for users managing peptide protocols, it keeps your dosing information organized and accessible.

**Highlights:** Log peptide and GLP-1 doses, Track vials, pens, and other supplies, Smart reminders for next doses, Home screen widgets, Estimated active level charts, Multi-peptide stack tracking, Reference pages for common compounds

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (7)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Stackr+ Weekly | $7.99 | per 7 days |
| Monthly | $12.99 | per month |
| Stackr+ Yearly | $29.99 | per year |
| Stackr+ Yearly | $49.99 | per year |
| Stackr+ Yearly | $49.99 | per year |
| Stackr+ Yearly | $59.99 | per year |
| Yearly | $69.99 | per year |


## Frequently asked questions

### Is VoltTimer free?

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

### Is Stackr free?

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

### Do VoltTimer or Stackr have ads?

Neither VoltTimer nor Stackr shows ads.

### Which is updated more often, VoltTimer or Stackr?

VoltTimer ships an update every 3 weeks, and Stackr every 4 days. Most recently, VoltTimer was updated on October 7, 2026 and Stackr on October 22, 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.*