CRSI Rebar Reference vs calc318
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
CRSI Rebar Reference
Access essential data for reinforcing bars (rebar) including specifications, hook details, and marking requirements. This app serves as a quick reference for industry standards and links to online resources.
- ASTM standard reinforcing bar specifications
- Standard hook details (90, 135, 180 degrees)
- Stirrup/tie hook details
- ASTM reinforcing bar marking requirements
- Minimum yield and tensile requirements
- Links to CRSI online resources
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QUICK REFERENCE! This ready reference app from the Concrete Reinforcing Steel Institute is a handy desk and field resource and includes information on ASTM standard reinforcing bars (rebar), standard hook details, standard stirrup/tie hook details, and ASTM reinforcing bar marking requirements. The app provides standard rebar specifications including sizes, diameters, areas and weights along with 90-, 135- and 180-degree hook details. Minimum yield and minimum tensile requirements per ASTM are also included. Industry standard bar markings for inch-pound rebar is illustrated for grades 40, 50, 60, 75, 80, 100 (A615), 100 (A1035), and 120. Links to the CRSI’s online resources are included.
calc318
Instantly solve 175 ACI 318-19 equations with live computation and interactive charts. Understand equation behavior with sensitivity graphs and clear variable descriptions. Designed for engineers needing quick, accurate calculations and insights.
- 175 ACI 318-19 equations solved instantly
- Live computation with unit awareness
- Interactive sensitivity graphs
- Professionally formatted equations
- Complete variable descriptions
- Smart search functionality
- Recents tab for quick access
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Solve all 175 equations from ACI 318-19 Appendix C, instantly, in US Customary Units. Calc318 turns the equations from ACI 318-19 Appendix C into a live calculator. Pick an equation, enter your parameters, and get an answer the moment you type — beautifully rendered, with every variable clearly defined and unit-aware. No spreadsheets, no hand calcs. calc318 requires an auto-renewable subscription. Start your 7-day free trial — no charge until the trial ends, and you can cancel anytime. After the trial, your subscription continues at $12.99/year or $2.99/month. Manage or cancel anytime in Settings → Apple ID → Subscriptions. See more than just a number. Tap any input to open an interactive chart that shows exactly how your result responds as that parameter changes — with a draggable point and a family of curves for the other key variables, so you understand the behavior of the equation, not just one data point. FEATURES: - Live computation for all 175 ACI 318-19 equations, fully unit-aware. - Professionally formatted equations with LaTeX-quality rendering. - Interactive sensitivity graphs — drag a point and watch the result update in real time. - Compare curves across multiple parameter values to see trends at a glance. - Complete variable descriptions and units for every input. - Smart search by section number, chapter, keyword, or variable. - Recents tab to jump back to equations you use most. - Clean, intuitive interface designed for engineers. Whether you're checking a calculation, running a quick sensitivity study, or referencing design provisions, calc318 gets you the answer — and the insight behind it — in seconds. Privacy Policy: https://aiosciv.com/calc318/ Terms of Use (EULA): http://www.apple.com/legal/itunes/appstore/dev/stdeula
Screenshots
Verdict
The clearest difference is review sentiment: calc318 at 100% against CRSI Rebar Reference's 33%. calc318 also leads on rating (5.0 vs 3.3). CRSI Rebar Reference's advantage is monetization model (free vs subscription) and ratings volume (16 vs 1). On price, 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
Both are free to download. CRSI Rebar Reference sells 3 one-off in-app purchases and calc318 sells 2 in-app purchases, starting at $2.99 per month. Whichever you choose, the download price is not the number that matters.
calc318 holds the better App Store score, 5.0 against 3.3. That said, the two scores are not equally well evidenced: CRSI Rebar Reference has 16 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 33% of CRSI Rebar Reference's written reviews are positive against 100% of calc318's.
CRSI Rebar Reference ships an update every 5 weeks, calc318 every 3 months. The most recent releases landed on October 4, 2026 and October 1, 2026 respectively.
| Parameter | CRSI Rebar Reference | calc318 |
|---|---|---|
| Price | Free | Free |
| Rating | 3.3 (16 ratings) | 5.0 (1 ratings) — better |
| Positive reviews | 33.3% of reviews | 100.0% of reviews — better |
| Number of ratings | 16 — better | 1 |
| Update frequency | Every 5 weeks — better | Every 3 months |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Monetization | Free — better | Subscription |
| Devices | iPhone, iPad, iPod — better | iPhone |
| Requires iOS | 15.1 — better | 26.0 |
| Further details — not scored | ||
| Size | 51 MB | 19 MB |
| Age rating | 17+ | 4+ |
| Developer | Concrete Reinforcing Steel Institute | ARTIFICIAL INTELLIGENCE OPTIMIZATION AND SOFTWARE AIOS LLC |
Customer experience
CRSI Rebar Reference
calc318
In-app purchases
CRSI Rebar Reference
- CRSI - Rebar Identifier Module$2.99
- CRSI Development Length ACI$4.99
- CRSI Development length AASHTO$4.99
calc318
- calc318 Pro Monthly7 Days trial$2.991 Month
- calc318 Pro Yearly7 Days trial$12.991 Year
Questions
Is CRSI Rebar Reference free?
Is calc318 free?
Which has better reviews, CRSI Rebar Reference or calc318?
Do CRSI Rebar Reference or calc318 have ads?
Which is updated more often, CRSI Rebar Reference or calc318?
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