Gas Blender Toolkit vs OVM
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Gas Blender Toolkit
This comprehensive toolkit assists scuba divers in calculating and blending various gas mixtures like trimix, nitrox, and heliox. It offers features for both partial pressure and continuous blending, cost calculation, and utilizes ideal and real gas models for accuracy. Optimized for larger screens, it serves as a successor to a previous diving application.
- Partial pressure blending
- Continuous blending
- Trimix, nitrox, heliox calculations
- Ideal and real gas models
- Cost calculation
- Top off from storage
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Gas Blender Toolkit is a comprehensive, purpose-built calculator for technical and recreational scuba divers who blend their own breathing gases. FUNCTIONS • Partial-pressure gas blending with freely configurable fill order • Continuous / delta-gas blending method • Decanting from a storage bank, with calculation of the number of possible fills • MOD / END tables for standard scuba gases • pSCR loop oxygen-reduction calculation at constant volume ratio • CCR rebreather diluent END calculator for any depth and chosen PPO2 setpoint FEATURES • Real gas (Van der Waals) or ideal gas calculations • Cost calculation for each gas fill • Fully customizable standard gas list • Accounts for gas heating during filling • Clean, fast and easy to use • Available in English, German, Russian and Spanish Gas Blender Toolkit is the completely rewritten successor to the DIR-Wetnotes app, redesigned from the ground
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 price: Gas Blender Toolkit at $2.99 against OVM's $7.99. Gas Blender Toolkit also leads on update cadence (every 9 days vs monthly) and device support (3 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
Gas Blender Toolkit costs $2.99 and OVM $7.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Gas Blender Toolkit ships an update every 9 days, OVM monthly. The most recent releases landed on November 6, 2026 and October 25, 2026 respectively.
| Parameter | Gas Blender Toolkit | OVM |
|---|---|---|
| Price | $2.99 — better | $7.99 |
| Rating | 3.0 (2 ratings) — better | — |
| Positive reviews | 60.0% of reviews | — |
| Number of ratings | 2 — better | — |
| Update frequency | Every 9 days — better | Monthly |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | — |
| Devices | iPhone, iPad, iPod — better | iPhone |
| Requires iOS | 15.0 — better | 16.6 |
| Further details — not scored | ||
| Size | 3 MB | 2 MB |
| Age rating | 4+ | 17+ |
| Developer | Oleg Gurevich | data-project bv |
In-app purchases
Gas Blender Toolkit
No in-app purchases
OVM
No in-app purchases







