Delta Calc vs Memory Roulette
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Delta Calc
Quickly calculate percent changes, discounts, and financial gains without complex math. Solve for any of the three values in the percent change formula with an intuitive interface and fun animations.
- Calculate percent changes
- Solve for any variable in the formula
- Customizable decimal places
- Haptic feedback
- Fun animations
- Adjustable keyboard buttons
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A fast, easy, and fun-to-use percent change calculator. Now you can quickly calculate discounts, financial gains, and percent changes without having to use Excel, Google, or do the long math. Delta Calc can solve for any of the three values within the percent change formula. It solves for the a, b, or c value in the percent change formula ((b - a) / a) * 100 = c. Other features include: - Haptic feedback (can be disabled if desired) - Change the number of decimal places displayed in the result (from 0 to 10) - Fun animation when tapping the swap button (warning: could become addictive) - Delightful to tap number pad buttons - Enable and disable keyboard buttons Terms: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy: https://deltacalc.app/privacy Support: https://deltacalc.app/support
Memory Roulette
Transform your cluttered camera roll into a curated collection of cherished memories. This app gamifies photo organization, offering daily surprise selections for quick review and decluttering. Rediscover forgotten moments and enjoy a cleaner, more meaningful photo library.
- Daily surprise photo crates
- 3-second swipe review (Favorite, Share, Delete)
- Gamified photo decluttering
- Unlimited draws with premium
- Customizable roulette filters (year, location, type)
- Rediscover forgotten memories
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This application adheres to the Apple Standard End User License Agreement (EULA). For detailed terms, please refer to: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ - STOP PHOTO CLUTTER. START REDISCOVERING YOUR PAST. Who has the time to organize a camera roll with thousands of forgotten photos? They just sit there, wasting storage and hiding the memories that truly matter. Memory Roulette turns organization into a fun, quick, and rewarding daily habit. No more stressful scrolling—just pure nostalgia and easy decluttering. - How it Works: Your Daily Memory Spin We gamify your cleanup process by turning photo management into a surprise draw: The Daily Crate: Get a surprise 'Crate' of 5 random photos or videos you haven't seen in months. It's like opening a digital time capsule. 3-Second Curator: Review each moment instantly and swipe to decide: Favorite, Share, or Delete. Do it during your coffee break, waiting in line, or before bed. Relive the Joy: Rediscover those funny, blurry, and forgotten moments—from your pet’s first great escape to the best slice of pizza you ever ate. - Go Premium: Unlock Full Control Ready for a deep clean? Upgrade to unlock our most powerful tools: Unlimited Draws: Clean up your entire photo library at your own pace. Custom Roulette Rules: Filter the Crate content by year, location, or type (e.g., "Only show me photos from last summer’s trip to Japan"). Download Memory Roulette now and turn your messy camera roll back into a beautiful collection of memories.
Screenshots
Verdict
The clearest difference is price: Memory Roulette at Free against Delta Calc's $0.99. Memory Roulette also leads on iOS requirement (14.0 vs 17.6). On rating, ratings volume, update cadence and ads 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
Memory Roulette is free to download; Delta Calc costs $0.99 up front. Delta Calc sells 3 in-app purchases, starting at $0.99 per month and Memory Roulette sells 3 in-app purchases, starting at $5.99 per month. Whichever you choose, the download price is not the number that matters.
On the App Store both sit at effectively the same score — 5.0 for Delta Calc against 5.0 for Memory Roulette. Both are backed by a comparable volume of ratings — 2 and 1 respectively.
Delta Calc ships an update every 3 days, Memory Roulette every 4 days. The most recent releases landed on June 1, 2026 and August 14, 2026 respectively.
| Parameter | Delta Calc | Memory Roulette |
|---|---|---|
| Price | $0.99 | Free — better |
| Rating | 5.0 (2 ratings) | 5.0 (1 ratings) |
| Positive reviews | — | 100.0% of reviews |
| Number of ratings | 2 — better | 1 |
| Update frequency | Every 3 days — better | Every 4 days |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Paid | Free with in-app purchases — better |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 17.6 | 14.0 — better |
| Further details — not scored | ||
| Size | 2 MB | 37 MB |
| Age rating | 4+ | 4+ |
| Developer | Stephen Coffey | 志文 李 |
Customer experience
Delta Calc
Memory Roulette
In-app purchases
Delta Calc
- Delta Calc Monthly$0.991 Month
- Delta Calc Yearly$4.991 Year
- Delta Calc Lifetime$9.99
Memory Roulette
- Monthly Subscription$5.991 Month
- Yearly Subscription$49.991 Year
- lifetime$39.99









