Comparison

Bolt Torque Spec Calc vs Voltary

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

Head to head
About

Bolt Torque Spec Calc

Features
Currently charting
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Built for mechanics, millwrights, and equipment installers who need bolt torque on the bench - not a desktop tool. WHAT IT DOES Looks up torque values for standard bolt sizes and grades using the T = K x D x F formula with K = 0.20. SAE grades 2, 5, and 8 across 28 sizes from #6-32 to 1-1/2 inch. Metric classes 4.6, 8.8, 10.9, and 12.9 across 17 sizes from M3 to M36. Dry vs. lubricated multiplier applied to the result. INPUTS - Standard: SAE or Metric - Bolt size (28 SAE or 17 metric sizes available) - Bolt grade or class - Lube condition: Dry or Lubricated RETURNS - Torque in ft-lb - Torque in NĀ·m CALCULATION BASIS - Torque formula: T = 0.20 x D x F - Preload F = 75% of proof strength times tensile stress area - Lubricated multiplier: 0.75 times the dry value WHY THIS APP, NOT THE FREE ONES - Math is shown - formula and assumed K factor visible, not hidden. - 45 size and grade combinations covered in one tap. - Works offline - shop floor, field repair, no Wi-Fi. Always available. - No login. No ads. No telemetry. No subscription. PRICING $1.99. Pay once, own it. Lifetime access on iPhone, iPad, and Mac via Family Sharing. NOT A SUBSTITUTE FOR Manufacturer-specified torque values for safety-critical fasteners. Calibrated wrench certificates. Specific K-factor adjustments for anti-seize, plating, or galvanized threads - this app uses K = 0.20 for both dry and lubricated, with the 0.75x multiplier as the only lube adjustment. Verify against the OEM tightening spec for the specific application.

About

Voltary

Features
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Voltary is the offline electronics bench that lives in your pocket — a fast, private toolkit of calculators, connector pin-outs, reference tables and a schematic sketchpad, built for engineers, students, makers and repair techs. No account, no sign-up, no internet required. Everything works on the bench, in the field, or on a plane. WHY "OFFLINE"? Every feature in Voltary runs entirely on your device. All calculators, pin-out diagrams, reference tables and the sketchpad are built into the app and computed locally — so the app needs no internet connection, no server and no account to do its job. You can use the whole app in Airplane Mode. (The only optional network use is ads; they are never required to use any tool.) FREE — NO PAID FEATURES Voltary is completely free. There are no in-app purchases, no subscriptions and nothing locked behind a paywall — every tool, table and diagram is fully available to everyone. The app is simply supported by ads. CALCULATORS & CONVERTERS (40+) Solve the everyday electronics math in seconds — enter any values and Voltary computes the rest, in clean engineering notation with proper SI prefixes. • Ohm's law, power & dissipation • LED series resistor, voltage divider, Zener • Reactance & resonance, RC/RL/LC filters • 555 timer, LM317 regulator, op-amp gain • Capacitor charge, series/parallel R & C • Inductor design, Y-Ī” transform, RTD/PT100 • Battery life, voltage drop, PCB trace width • Resistor & inductor colour-code decoders • SMD code lookup, dB, number-base & unit converters Long-press a result to send a value straight into another tool — no retyping. PIN-OUTS (39 connectors, real diagrams) Stop hunting through datasheets. Voltary ships accurate, colour-coded pin-outs you can tap and zoom: • USB Type-A & Type-C, HDMI, DisplayPort, VGA • Ethernet RJ-45 (T568B), SATA, ATX power • Raspberry Pi 40-pin GPIO, GPIB and many more Pins are grouped by function (power, ground, data, clock) so wiring is obvious at a glance. REFERENCE LIBRARY A built-in shelf of the tables you keep looking up: • SI unit prefixes, E12/E24 standard values • AWG wire size, PCB resistivity • IP ingress-protection codes • Logic-gate truth tables, ASCII table • Blade-fuse colours, battery types • SMD package sizes, 7400-series logic • A searchable schematic-symbol gallery SCHEMATIC SKETCHPAD Capture an idea before it's gone. Drop components, route wires, add labels and text on an infinite grid, then save your sketches or share them as a PNG. BUILT FOR REAL WORK • 100% offline — every tool, table and diagram is on-device • Free, with no in-app purchases or subscriptions • Engineering notation with tabular figures (no jittering columns) • Light & dark themes, edge-to-edge modern design • Fast, native, and respectful of your data • Available in 14 languages: English, Spanish, Portuguese, Arabic, French, German, Russian, Hindi, Indonesian, Turkish, Japanese, Korean, Simplified Chinese and Italian — including full right-to-left layout PRIVATE BY DESIGN Voltary doesn't ask you to create an account and doesn't need the network to do its job. It's a tool, not a service. Whether you're sizing a current-limiting resistor, wiring a USB-C connector, checking an AWG rating or sketching a quick circuit, Voltary puts the whole bench one tap away. Download Voltary and keep your electronics reference, math and notes in one place — always offline, always ready.

Screenshots

Bolt Torque Spec Calc3 screens
Voltary4 screens

Verdict

The call

The clearest difference is price: Voltary at Free against Bolt Torque Spec Calc's $4.99. Voltary also leads on iOS requirement (13.0 vs 17.0). Bolt Torque Spec Calc's advantage is ads (none vs shown) and chart position (#195 vs unranked). On in-app purchases and device support there is nothing between them.

Scored on Price Ā· Rating Ā· Positive reviews Ā· Number of ratings Ā· Update frequency Ā· Ads Ā· In-app purchases Ā· Monetization Ā· Best chart rank Ā· Devices Ā· Requires iOS

CostPrice Ā· In-app purchases Ā· Ads Ā· Monetization

Voltary is free to download; Bolt Torque Spec Calc costs $4.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Scorecard4 real differences Ā· 3 level
Bolt Torque Spec Calc versus Voltary: the parameters behind the verdict, then further details
ParameterBolt Torque Spec CalcVoltary
Price$4.99Free — better
Update frequencyEvery 3 weeks—
AdsNo — betterYes
In-app purchasesNoNo
Best chart rank#195 — better—
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS17.013.0 — better
Further details — not scored
Size1 MB45 MB
Age rating4+4+
DeveloperShanghai Sheyuan Network Technology Co., Ltd.Hasanain Alhamedi

In-app purchases

None

Bolt Torque Spec Calc

No in-app purchases

None

Voltary

No in-app purchases

Questions

Is Bolt Torque Spec Calc free?
Bolt Torque Spec Calc costs $4.99, with no in-app purchases.
Is Voltary free?
Voltary is free to download, with no in-app purchases.
Do Bolt Torque Spec Calc or Voltary have ads?
Voltary shows ads; Bolt Torque Spec Calc does not.

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