Bunker One vs Oilcalcs
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Bunker One
This app provides a suite of calculators for marine fuel standards, including CCAI, Cetan Index, and blending calculations. It supports ISO 8217 and ASTM standards, with all inputs and outputs in SI units. Users can also access news and updates from the developer.
- ISO 8217 fuel standard lookup
- CCAI Number calculation
- Cetan Index calculation (old & new methods)
- Fuel blending calculators (viscosity, sulphur)
- Injection temperature calculation
- Energy and price relation calculations
- News updates from developer
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This application by Bunker One, is a small practicable tool for look up the ISO 8217 - 2005, 2010/2012, 2017 & 2024 standards for residual- and distillate marine fuels. Programmed calculators are included for different fuel related calculations. Calculators programmed as below.: -CCAI Number according ISO 8217 -Cetan Index ASTM - D 976 - 80 (old method) ASTM - D 4737 - 87 (new method) -Deviation calculations according Bunker One -Energy and price relations according Bunker One -Fuel Blending - Viscosity blending according ASTM - D 7152 Sulphur blending according Bunker One -Injection temperature according Bunker One -Reproducibility -Specific Energy gross and net content according ISO 8217 -Viscosity Index according ASTM - D 341 -Volume Correction Factor according ASTM D1250-80 Table 5B General for all calculators is that all entries shall be in SI units. And results also given in SI units. Where there is a differentiation between Distillates and Residual fuels, distillates are defined with density lower than 900 kg/m3 Where there is a differentiation between Straight Run fuel and Cracked fuels, straight run fuels are defined with density lower than 950 kg/m3 News published on our web page Bunkerone.com will be pushed to the app holders and publish with link to the web under the "news" bar
Oilcalcs
This app provides comprehensive calculations for professionals in the oil and gas industry. It offers versatile tools for volume and weight conversions, density corrections, and blending calculations, supporting various industry tables and units.
- Volume and weight conversions
- Density correction for special applications
- Viscosity, pour point, and flash point blender
- LNG and LPG density calculators
- Support for ASTM tables and units
- Data export to database
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The most complete, flexible and versatile calculator for professionals in the oil and gas industry! Now optimized for iOS 26. Newly added features: - Calculator for Aromatics - Added the following tables to the oil conversion screen: table 4, 8, 9, 10, 11, 12, 13, 14, 52, 56, 57, 58 - Added a field for density correction in the main calculator (and quantity editor) for the calculation of special applications in case a thermal expansion coefficient is not available - Viscosity / pour point / flash point blender - LNG density calculator - Viscosity / Temperature calculator - Density data for both the LPG and LNG density calculator are stored in the phone for easy retrieval The app uses the ASTM tables / formulas to calculate weights and volumes based on entered density15, density20, relative density or API, observed volume, pressure and temperature, and calculates the following: - Volume correction factor (to number of decimals of your own choice or as set by table Version) - Metric tons (vacuum) - Metric tons (air) - GSV (M3 @15) - BBLS (@60) - Longtons - Gallons OilCalcs contains both ASTM 1980 and ASTM 2009 tables as well as the ASTM 1952 version of LPG Table 54, and users can select which table to use in the settings screen. Users can also select whether they want to calculate using SI Metric units or Imperial units. Precision for VCF, GSV, MTons, LTons and Bbls can be changed using the settings screen. Settings are saved in the app so that when you use the app next time it will calculate with your chosen settings. Densities can be entered in the following formats which are automatically recognized: e.g 0.9664 / 966.4 / 9664 The app can calculate for crude oil, black and white products, lubrication oils and special applications, and input can be changed between density in vacuum at 15 and 20 deg C/ API / relative density / observed, and degrees Celsius / Fahrenheit by touching the applicable buttons. The user has the choice to calculate using as input observed M3 / M3 at 15 / observed Barrels / Barrels 60 / Metric tons air/vac / Ltons / Gallons. The user can also calculate weights of LPG / NGL, using either density @ 15C, relative density @60F, observed density or density @ 20C. Aside from the conversion screen with conversions between API, observed density, density 15, density 20 and relative density, there is also a screen with conversions used in LPG / NGL. For products, lube oils and crude there are two tools for calculating final density when blending two components: one tool that calculates the blend after loading the 2nd component, and another tool that lets the user choose the two components and advises which component to load first, based on density 15C or API 60F and actual temperature of the components. Both tools also calculate volume shrinkage due to blending. A utility has been included that enables the user to export data from the calculator screen directly into a database for future reference. The same utility can be used to enter data manually and edit previously entered data. For a detailed tutorial please visit our webpage (http://mooringmarineconsultancy.wordpress.com). Download the manual here: https://mooringmarineconsultancy.wordpress.com/wp-content/uploads/2020/09/oilcalcs-for-iphone-user-manual.pdf
Screenshots
Verdict
The clearest difference is review sentiment: Oilcalcs at 100% against Bunker One's 0%. Oilcalcs also leads on rating (4.8 vs 4.5) and ratings volume (46 vs 2). Bunker One's advantage is price (Free vs $9.99). On update cadence, ads, 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
Bunker One is free to download; Oilcalcs costs $9.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Oilcalcs holds the better App Store score, 4.8 against 4.5. That said, the two scores are not equally well evidenced: Oilcalcs has 46 ratings behind it against 2, so its average is the more settled of the two. Written reviews point the same way: 0% of Bunker One's written reviews are positive against 100% of Oilcalcs's.
Bunker One ships an update every 3 months, Oilcalcs every 4 months. The most recent releases landed on October 23, 2026 and October 26, 2026 respectively.
| Parameter | Bunker One | Oilcalcs |
|---|---|---|
| Price | Free — better | $9.99 |
| Rating | 4.5 (2 ratings) | 4.8 (46 ratings) — better |
| Positive reviews | 0.0% of reviews | 100.0% of reviews — better |
| Number of ratings | 2 | 46 — better |
| Update frequency | Every 3 months — better | Every 4 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Free — better | Paid |
| Devices | iPhone, iPod | iPhone, iPod |
| Requires iOS | 15.6 | 15.6 |
| Further details — not scored | ||
| Size | 16 MB | 2 MB |
| Age rating | 4+ | 4+ |
| Developer | Askapps | ron mooring |
Customer experience
Bunker One
Oilcalcs
In-app purchases
Bunker One
No in-app purchases
Oilcalcs
No in-app purchases








