DragCalc vs RigMaster
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
DragCalc
This app predicts drag racing performance metrics like quarter-mile times and trap speeds using a physics-based simulation. It allows users to input car specifications, compare different builds, and analyze real-world runs.
- AI-powered car input
- Quarter & Eighth Mile ET/trap speed predictions
- Side-by-side car build comparison
- Slope correction for track grade
- Analysis of imported run data
- Cloud sync for presets
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DragCalc is the ultimate drag racing performance calculator. Predict your quarter-mile times, trap speeds, and acceleration metrics with physics-based simulation. FEATURES: • AI-Powered Input — Describe any car and get instant specs • Quarter & Eighth Mile — Accurate ET and trap speed predictions • Compare Builds — Race up to 4 cars side-by-side with animated simulation • Slope Correction — Correct your times for track grade • Analyze Runs — Import Dragy CSV files or timeslips • Cloud Sync — Sign in to save presets across devices PHYSICS ENGINE: • Real tire compounds (slicks, radials, street) • Surface grip modeling (prep, asphalt, concrete) • Drivetrain losses and transmission efficiency
RigMaster
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RigMaster is the rigging calculator built for working riggers, crane operators, and signal persons. LIFT PLAN PDF (PRO) • Turn any calculation into a one-page lift plan: diagram, inputs, results • Room for notes and three signature lines — prepared by, signature, date • Share it straight to the supervisor from the toolbar IPAD & UNITS • Universal app — two-column layout on iPad, any orientation • Metric or imperial — kg and metres or lb and feet, switch any time • Live sling diagram with the angle and tension on every leg FREE CALCULATORS • Sling Tension — 2-leg picks by angle, or by sling length & height (the way you actually measure) • Hitch Capacity — vertical, choker (reduced by the choke angle) and basket capacity from YOUR sling's tag rating • Angle Reference — the tension multiplier table, always in your pocket PRO CALCULATORS • 3 & 4-leg bridles with rigid/flexible load sharing • Unequal Legs / CoG Offset — tension per leg when the center of gravity isn't centered • Horizontal pull per leg — the compression a spreader beam has to carry • Load Weight Estimator — steel, concrete, aluminum and more, by shape and dimensions • Ad-free Built on first-principles trigonometry with warnings at 45° and hard alerts below 30°, following standard rigging practice (ASME B30.9 guidance). RigMaster is an estimation aid for qualified riggers. Always follow the sling tag, the load chart, and your site's rigging plan. COMMON QUESTIONS Does it work offline? Yes. Every calculation runs on the phone. No signal needed on site. Do I need an account? No. There is no login and no sign-up. What is free? Sling Tension, Hitch Capacity and the Angle Reference table are free. Pro adds 3 and 4-leg bridles, unequal legs with CoG offset, the load weight estimator and the lift plan PDF, and removes the ads. Metric or imperial? Both, switchable at any time — kg and metres, or lb and feet. Can I hand the result to the supervisor? Yes. Pro turns any calculation into a one-page lift plan PDF: diagram, inputs, results, notes and three signature lines. Does it replace the sling tag or the load chart? No. It is an estimation aid for qualified riggers. The sling tag, the load chart and your site's rigging plan always come first. Does it work on iPad? Yes. Universal app, two-column layout on iPad, any orientation. Terms of Use: https://ghapps1.wordpress.com/terms-condition/ Privacy Policy: https://ghapps1.wordpress.com/privacy-policy/
Screenshots
Verdict
The clearest difference is in-app purchases: DragCalc at none against RigMaster's 4. RigMaster's advantage is update cadence (every 11 days vs every 5 months). On price, ads, device support 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
Both are free to download. RigMaster sells 4 in-app purchases, starting at $0.99 per 7 days. DragCalc asks for nothing beyond the download.
DragCalc ships an update every 5 months, RigMaster every 11 days. The most recent releases landed on October 31, 2026 and November 6, 2026 respectively.
| Parameter | DragCalc | RigMaster |
|---|---|---|
| Price | Free | Free |
| Rating | 3.0 (1 ratings) — better | — |
| Positive reviews | 0.0% of reviews | — |
| Number of ratings | 1 — better | — |
| Update frequency | Every 5 months | Every 11 days — better |
| Ads | Yes | Yes |
| In-app purchases | No — better | Yes |
| Monetization | Ad-supported | — |
| Devices | iPhone | iPhone, iPad — better |
| Requires iOS | 18.1 | 17.0 — better |
| Further details — not scored | ||
| Size | 17 MB | 5 MB |
| Age rating | 4+ | 4+ |
| Developer | Sheharyar Irfan | Grima Hdez |
In-app purchases
DragCalc
No in-app purchases
RigMaster
- Pro Weekly$0.997 Days
- RigMaster Pro Monthly$2.991 Month
- Pro Yearly$19.991 Year
- RigMaster Pro$39.99









