Comparison

O vs Hydraulic Calculator Engineer

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

O

This app provides a comprehensive offline tool for selecting standard rubber seal sizes, including O-Rings, X-Rings, and Back-Up Rings. It offers dimension searches, housing calculations for various sealing applications, and supports multiple international standards in both metric and imperial units.

Highlights
  • Offline standard rubber seal size selection
  • Search for O-Ring, X-Ring, and Back-Up Ring sizes
  • O-Ring housing calculations for sealing applications
  • Supports multiple international standards (AS568, METRIC, JIS, etc.)
  • Metric and Imperial unit support
  • Substitutable O-Ring size suggestions
Features
Read full description

GMORS O-Ring Master is the completed tool for standard rubber seal sizes. When you use this APP, you don't need to have internet and catalog. Except O-Ring sizes, it also includes the search functions of X-Ring and Back-Up Ring. Otherwise, you can also use O-Ring Housing to choose suitable O-Ring in your application. Main functions are as follows: Dimension Search:O-Ring, X-Ring and Back-Up Ring. - MM and Inch are both available. - Full standard O-Ring series: AS568, BS 4518, GB/T 3452.1, JIS B2401 P, JIS B2401 G, JIS B2401 S, JIS B2401 V, SMS 1586 and METRIC. - Collocated Back-Up for AS-568 O-Ring. - Substitutable O-Ring sizes within tolerance are available. O-Ring Housing: Piston Sealing、Rod Sealing and Face Sealing. - MM and Inch are both available. - Support calculation for both Static and Dynamic sealing applications (Face sealing is with static calculation only). - Up to 7 O-Ring standards ( AS568, METRIC, JIS B2401 P/G/S/V, JASO F404, GB/T 3452.1, BS 4518 and SMS 1586) for most of size requirement of different groove design.

About

Hydraulic Calculator Engineer

This app offers a suite of hydraulic calculations for technicians and engineers. It simplifies complex hydraulics by automatically computing results based on user-entered values, eliminating the need for manual formula application.

Highlights
  • Cylinder Calculation
  • Power Calculation
  • Pressure Difference
  • Piston Diameter
  • Speed Calculation
  • Lifting Time
  • Volume Flow
Features
Read full description

Hydraulic Engineer Calculators is a practical hydraulic engineering calculator and formula app for engineers, technicians, students, contractors, operators, and anyone working with fluid flow, pipes, pumps, pressure, open channels, hydraulic cylinders, or fluid mechanics. Quickly enter your values, select units, calculate an estimate, review result details, and check the formula used. Hydraulic calculators included: Flow & Pipe Calculators - Pipe Flow Velocity - Calculate fluid velocity from flow rate and pipe diameter - Flow Rate - Calculate volumetric flow from flow area and average velocity - Required Pipe Diameter - Estimate pipe diameter from design flow and velocity - Reynolds Number - Calculate Reynolds number for internal fluid flow Head Loss Calculators - Darcy-Weisbach Head Loss - Estimate pipe friction head loss - Hazen-Williams Head Loss - Estimate water pipe friction loss - Minor Loss - Calculate losses from fittings, valves, entrances, exits, and components Pressure & Head Calculators - Pressure to Head - Convert pressure to hydraulic head - Head to Pressure - Convert hydraulic head to pressure - Hydrostatic Pressure - Calculate pressure caused by fluid depth - Bernoulli Total Head - Calculate total hydraulic head Pump Calculators - Pump Power - Estimate hydraulic pump power from flow, head, and efficiency - Pump Head from Pressure - Calculate pump head from pressure difference - NPSH Available - Estimate Net Positive Suction Head Available Open Channel Flow Calculators - Manning Rectangular Channel - Estimate rectangular channel flow - Froude Number - Calculate the Froude number - Critical Depth - Estimate critical water depth - Orifice Flow - Calculate fluid discharge through an orifice Hydraulic System Calculators - Water Hammer Pressure - Estimate pressure rise from a rapid velocity change - Hydraulic Cylinder Force - Calculate cylinder force from pressure and piston area - Hydraulic Cylinder Speed - Calculate piston speed from flow rate and bore diameter Fluid Properties Calculator - Specific Gravity - Calculate specific gravity from fluid density Useful for: - Hydraulic engineering - Fluid mechanics - Pipe flow and pipe sizing - Water flow and pressure - Head loss and pipe friction - Pump systems and pump power - NPSH calculations - Open channel flow - Hydraulic cylinders - Water hammer - Irrigation, plumbing, water, and wastewater systems - Civil and mechanical engineering Supported units include: - m, mm, cm, ft, in - m², cm², mm², ft², in² - m³/s, m³/h, L/s, L/min, US gpm, ft³/s - Pa, kPa, MPa, bar, psi - m/s, ft/s - W, kW, hp Built-in formula guide Each calculator includes its formula, and the app links to a Hydraulic Engineer Guide with additional information about formulas, variables, units, calculation steps, practical uses, and important considerations. Selected calculators also include dynamic diagrams to help visualize values used in pipe, pressure, head, open channel, tank, and hydraulic cylinder calculations. Simple workflow: - Choose a calculator - Enter your known values - Select units - Tap Calculate - Review the result and details - Check the formula - Open the related guide for more information The built-in search makes it easy to find a specific hydraulic calculator by category or name. Important disclaimer These calculators provide preliminary hydraulic estimates only. Results are not a substitute for professional engineering judgment, certified calculations, manufacturer specifications, site-specific analysis, or applicable codes and standards. Always verify input values, units, fluid properties, pipe specifications, equipment limitations, safety factors, operating conditions, site conditions, and governing requirements before using a calculation for design, procurement, installation, testing, operation, maintenance, or any safety-critical application.

Screenshots

O4 screens
Hydraulic Calculator Engineer4 screens

Verdict

The call

The clearest difference is rating: O at 5.0 against Hydraulic Calculator Engineer's 4.3. Hydraulic Calculator Engineer's advantage is ratings volume (9 vs 1) and device support (3 vs 1). On price, update cadence, ads and in-app purchases 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

O holds the better App Store score, 5.0 against 4.3. That said, the two scores are not equally well evidenced: Hydraulic Calculator Engineer has 9 ratings behind it against 1, so its average is the more settled of the two.

UpkeepUpdate frequency

O ships an update every 11 months, Hydraulic Calculator Engineer every 22 months. The most recent releases landed on September 22, 2026 and September 10, 2026 respectively.

Scorecard3 real differences · 7 level
O versus Hydraulic Calculator Engineer: the parameters behind the verdict, then further details
ParameterOHydraulic Calculator Engineer
PriceFreeFree
Rating5.0 (1 ratings) — better4.3 (9 ratings)
Positive reviews0.0% of reviews
Number of ratings19 — better
Update frequencyEvery 11 months — betterEvery 22 months
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPhoneiPhone, iPad, iPod — better
Requires iOS16.015.0 — better
Further details — not scored
Size47 MB21 MB
Age rating4+4+
DeveloperGE MAO RUBBER INDUSTRIAL CO., LTD.Arsosa Network Inc.

Customer experience

O

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

Hydraulic Calculator Engineer

All ratings9 ratings
Positive88.9%
Neutral0.0%
Negative11.1%
Written reviews1 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

In-app purchases

None

O

No in-app purchases

None

Hydraulic Calculator Engineer

No in-app purchases

Questions

Is O free?
O is free to download, with no in-app purchases.
Is Hydraulic Calculator Engineer free?
Hydraulic Calculator Engineer is free to download, with no in-app purchases.
Which has better reviews, O or Hydraulic Calculator Engineer?
O is rated higher. O averages 5.0 out of 5 from 1 ratings, while Hydraulic Calculator Engineer averages 4.3 from 9 ratings.
Do O or Hydraulic Calculator Engineer have ads?
Neither O nor Hydraulic Calculator Engineer shows ads.
Which is updated more often, O or Hydraulic Calculator Engineer?
O ships an update every 11 months, and Hydraulic Calculator Engineer every 22 months. Most recently, O was updated on September 22, 2026 and Hydraulic Calculator Engineer on September 10, 2026.

Other comparisons