Comparison

leaDCalc vs Prompt Stock

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

Head to head
About

leaDCalc

This app calculates DC power lead sizes for telephone company central office power plants. It uses a circular slide rule format to determine allowable voltage drops and wire sizes based on specific system parameters.

Highlights
  • Circular slide rule format
  • Calculates allowable voltage drops
  • Determines DC power lead sizes
  • Supports 48V and 24V DC systems
  • References Bell System calculations
  • Informational use guide
Features
Read full description

Application based on the Western Electric Co. Inc, Bell Laboratories, Bell System DC Power Lead Calculator which is in a circular slide rule format.   Using allowable voltage drops specifically designed for telephone company central office direct current power plants and distribution wiring. The application references 48 volt battery systems but also works for other direct current voltages such as 24 volt. When using for 24 volts or other, choose by the required loop voltage drop instead of the specific section of the circuit. Notes: 51. Voltage drop and wire size calculations are based on 2.00 volt LOOP drop from the power plant battery to the load equipment and return. 1.75 Final Volts Per Cell or 40 volts min. operating volts at the equipment for nominal 48V systems.
 (40 + 2 = 42 / 24 = 1.75fvpc) 

 52. LOOP length is used in the calculations, often the battery and returns are unequal length. The result VD is shown as ONE WAY.

 53. The formula used in the lead size calculations is:
CM = LoopLength * 11.1 * Fuse or Breaker @ 100% / VD
(T-Mobile does use 80% of the input breaker or fuse size to calculate DC power wires)
CM = LoopLength * 11.1 * Fuse or Breaker @ 80% / VD
For example the Bell System might use the leaDCalc recommended 66% of the input breaker or fuse size to calculate DC power wires. The Bell System terms Peak and Busy Hour are antiquated electro-mechanical switch central office terms so leaDCalc recommends using 66% of the input fuse or breaker size, ie. 600A fuse or breaker calculate using 400 amperes and which is exactly as was done at Western Electric Co., Inc. for Bell System Telephone offices. 54. BDFB is a Battery Distributing Fuse Board. Fuse Panel is rack mounted at or near the load equipment. Load Equipment is the actual device requiring power. 

 55. This application is intended for informational use. Based on the original Bell System Lead Calculator, Western Electric Co., Inc. Model GS-5420, 4-66.

 56. "leaDCalc" is NOT affiliated with any person or company or anything else anywhere. No how, no way. 
Especially NOT T-Mobile nor the Bell System or even Western Electric Co. Inc., all of whom are mentioned. 
This application is meant as a guide only in determining the size and or capacities of power wiring used in direct current (DC), charging and storage battery telephone systems. 
This application is NOT intended to decide what type of wire, (or if you should even use wire or busbars in your DC systems), no how, no way and it is not for use with alternating current (AC) systems.

About

Prompt Stock

Features
Read full description

Prompt Stock helps you save prompts you use with ChatGPT and other AI tools, then copy them whenever you need them. Organize prompts by title, category, and favorites. Search and filters make it easy to find the right prompt as your collection grows. Main features: - Save, edit, and delete prompts - Copy from the list with one tap - Review the full prompt and copy from the detail screen - Mark favorites and filter by favorites - Search by title, body, or category - Organize with categories and sorting - Light mode, dark mode, and system appearance support Your prompts stay on your device and are not sent to the developer's servers.

Screenshots

leaDCalc4 screens
Prompt Stock4 screens

Verdict

The call

The clearest difference is update cadence: Prompt Stock at every 3 days against leaDCalc's every 7 months. On price, 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

CostPrice · In-app purchases · Ads · Monetization

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

UpkeepUpdate frequency

leaDCalc ships an update every 7 months, Prompt Stock every 3 days. The most recent releases landed on November 3, 2026 and October 31, 2026 respectively.

Scorecard1 real difference · 8 level
leaDCalc versus Prompt Stock: the parameters behind the verdict, then further details
ParameterleaDCalcPrompt Stock
PriceFreeFree
Rating5.0 (1 ratings) — better—
Number of ratings1 — better—
Update frequencyEvery 7 monthsEvery 3 days — better
AdsNoNo
In-app purchasesNoNo
MonetizationFree—
DevicesiPhone, iPad — betteriPhone
Requires iOS16.0 — better17.0
Further details — not scored
Size159 MB1 MB
Age rating4+4+
DeveloperVaughn WarrinerYasuyuki Arata

In-app purchases

None

leaDCalc

No in-app purchases

None

Prompt Stock

No in-app purchases

Questions

Is leaDCalc free?
leaDCalc is free to download, with no in-app purchases.
Is Prompt Stock free?
Prompt Stock is free to download, with no in-app purchases.
Do leaDCalc or Prompt Stock have ads?
Neither leaDCalc nor Prompt Stock shows ads.
Which is updated more often, leaDCalc or Prompt Stock?
leaDCalc ships an update every 7 months, and Prompt Stock every 3 days. Most recently, leaDCalc was updated on November 3, 2026 and Prompt Stock on October 31, 2026.

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