Trimix Tools vs OVM
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Trimix Tools
This app provides essential tools for divers to plan and blend Trimix gases. It calculates optimal mixes based on depth, oxygen partial pressure, and equivalent narcotic depth, and supports various cylinder filling scenarios. Calculations are available offline and can be customized with saved settings.
- Trimix blending and planning
- Depth and partial pressure calculations
- Equivalent Narcotic Depth (END) calculation
- Saltwater and freshwater support
- Cylinder filling and bleed down calculations
- Metric and Imperial system support
- Offline functionality
- Saved settings and custom mixes
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Trimix blending and planning tools that can be used where you are and when you need them. You can use these tools to plan your mixes prior to arriving at the dive shop or to fill your cylinder at the air station or on the boat. Calculations are provided for the best Trimix given a planned depth and a desired maximum partial pressure of oxygen and equivalent narcotic depth (END). You can also calculate the ceiling and maximum depths along with your END based on your planned mix. The dive planning tools support both salt water and fresh water calculations. The blending tools provide for filling a cylinder with a remaining mix (or empty) to a specified target mix using oxygen, helium and a topping mix (air or another available mix). You can also calculate the result of topping an existing partially filled cylinder with a specific topping mix (air or another available mix). There is also a Bleed Down calculator that allows you adjust an existing full or partially full cylinder to a new mix with minimal wasted gas. Trimix Tools supports calculations in both metric and Imperial/US systems of measure. Traveling on a boat or working out of network range? These tools are at hand any time you have your iPhone, iPad or iPod touch. You could, for example, easily calculate the result of topping your cylinder from your first dive with air from the boat's compressor to take advantage of any remaining mix. You also have the convenience of saved settings that you can recall at a touch and adjust to a new situation as needed. Chances are you regularly work with a specific set of mixes and common dive situations. Trimix Tools includes the convenience of saved settings that you can recall and adjust to a new situation as needed. You can also select mix values using pre-installed default mixes or your own saved custom mixes. When updating one of the mixes for a tool you are offered a list of saved mixes that you can use directly or adjust as needed. You can save the currently displayed mix by tapping on the "+" button. Just like with the saved calculations, you can re-arrange or delete any mixes in your saved list. Do you need to share your planning or blending calculations with other divers? All the tools have the ability to share the results of the calculations from within the application. You can set default email addresses and a subject Trimix Tool's settings that will be automatically added when you share a result. All END calculations (Dive Planning and Best Trimix tabs) in Trimix Tools treat oxygen as a narcotic gas by default. There is an option available under the Settings tab to change the default so that oxygen is not treated as narcotic if that is your preference. Remember you must always personally analyze your mix before diving it. This application is not a substitute for proper training and should not be used as a substitute for proper dive planning or the primary Trimix blending and planning methods taught during training. Please do not attempt to handle high pressure oxygen or fill SCUBA cylinders without proper training.
OVM
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OVM Diveplanner is an OC/CC (rebreather), mixed gas, multi-level, repetitive dive, decompression planner based on Bühlman ZHL/16C with configurable gradient factors or VPM/B. It tracks CNS and OTU's. Auto-calculates bailout profiles when in CCR mode. Create your dive profile by entering a list of depths of adding waypoints in the visual planner mode. Use predefined gasses or add your own custom mix. Also provides several gas mix tools for estimating gas results when topping off your tanks. This will give an estimate if boosting tanks leads to undisiarable results, before mixing. The app contains a user manual which is also available online at https://www.ovm-planner.com/user-manual.html. The app is intended for certified who whish to create an estimate of their dive profile and gas usages when executing deep decompression dives, helping in determining the required amount of decompression gas or bail-out gas needed. It can also be used to create an ascent profile to which you can fallback on when the divers computer fails underwater, or use for sanity checking you dive computer during the dive. The app works standalone and offline. It does not require an account and does not store any data except app settings such as breathing rate and entered dive settings. No external connections, software or hardware is required. No subscribtion of in-app purchases needed or possible.
Screenshots
Verdict
The clearest difference is update cadence: OVM at every 3 weeks against Trimix Tools's every 5 months. Trimix Tools's advantage is chart position (#197 vs unranked) and device support (4 vs 1). On ads, in-app purchases and iOS requirement 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
Trimix Tools costs $6.99 and OVM $7.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Trimix Tools ships an update every 5 months, OVM every 3 weeks. The most recent releases landed on September 10, 2026 and September 14, 2026 respectively.
| Parameter | Trimix Tools | OVM |
|---|---|---|
| Price | $6.99 — better | $7.99 |
| Rating | 5.0 (5 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 5 — better | — |
| Update frequency | Every 5 months | Every 3 weeks — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | — |
| Best chart rank | #197 — better | — |
| Devices | iPhone, iPad, iPod, Mac — better | iPhone |
| Requires iOS | 15.6 — better | 16.6 |
| Further details — not scored | ||
| Size | 6 MB | 1 MB |
| Age rating | 4+ | 17+ |
| Developer | Greg Mclaughlin | data-project bv |
In-app purchases
Trimix Tools
No in-app purchases
OVM
No in-app purchases









