App Overview

BuildCalc icon

BuildCalc

42nd Parallel · Utilities

What if you could take the best construction calculator and fix it

$24.99 · In-app purchases

PRICE
$24.99
In-app purchases
BUSINESS MODEL
Paid
No overall Grossing estimate available
RATING
4.7
71 ratings · Top 15%

Evidence scope: No current overall US chart position is available. Category-chart positions shown in discovery are a separate scope. Revenue is a directional model estimate, not verified earnings.

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Build Kit

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A product spec, screen plans, and build steps for your coding agent.

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What's included17 files

A product spec, phased build plan, differentiation notes, and screen references.

  • START_HERE
  • AGENTS
  • EVIDENCE
  • SPEC
  • BUILD_PLAN
  • DIFFERENTIATION
  • skills/
  • screens/
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Illustrative example: an invoice app for independent contractors. Your kit is tailored to the app you choose; this is not its generated content.

Feature spec

Goal: Send a clear invoice after finishing a job.

  • Add a client, line items, a due date, and payment instructions.
  • Preview the total before exporting a PDF.
  • Keep an editable draft if export fails.

Screen plan

Invoice editor: Client at the top, editable line items in the middle, total and preview action at the bottom.

States: Empty draft, validation errors beside each field, exporting, and a retry action that preserves the draft.

Differentiate and validate

Hypothesis: Contractors need faster repeat invoices more than more templates.

First experiment: Test duplicating a previous job with five contractors. Watch where they hesitate before expanding the feature set.

The full kit adds a phased build plan, evidence notes, tool prompts, and implementation guidance. It is a plan for your coding agent, not a finished app.

Usage: Mechanics are fair game; never reuse the original name, branding, assets, or verbatim copy.

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Quick prompt

> SELECT BUILD PLATFORM:

Good fit for mobile-first iOS and Android prototypes with managed app scaffolding.

// RORK SYSTEM PROMPT
Rork plan preview for BuildCalc: map the core Utilities workflow, choose the smallest differentiated feature set, define the data and monetization boundaries, then prototype the riskiest user journey first.
            

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Opportunities

AI-GENERATED OPPORTUNITY HYPOTHESES

These are generated suggestions, not verified review quotations. Check current App Store reviews and speak with users before treating a possible gap as a requirement.

Hypothesis 1

Add more calculators and features for increased user engagement.

Assumption to check: Limited functionality compared to more comprehensive calculators

Validate with people who use this workflow before building.

Hypothesis 2

Simplify navigation and provide onboarding tutorials.

Assumption to check: Interface can be confusing for new users

Validate with people who use this workflow before building.

Hypothesis 3

Allow users to customize and save their favorite calculations.

Assumption to check: Lack of customization options for users

Validate with people who use this workflow before building.

Hypothesis 4

Implement a free trial and subscription model to attract more users.

Assumption to check: High upfront cost for the app

Validate with people who use this workflow before building.

App evidence

Original App Store material. Ratings and screenshots describe the existing app, not proof of demand for your version.

App Store description

What if you could take the best construction calculator and fix it. That’s right ... you love it, it has served you well, and you stand by it ... but could it do more? Could it be easier to use? After testing by pros from around the world, BuildCalc is ready to give you more - more function and more answers with less complexity, less hassle, and less confusion. MORE FUNCTIONALITY: • Advanced Baluster Function: Complete layout of railing and staircase balusters with less guess work - and with all the flexibility you need for every custom job. • Advanced Stair function: Stair layouts for professional results - including dimensioned drawings of your Stringer, Stringer Installation, and Finished Staircase. And you can email a PDF of these drawings right from BuildCalc so you can print them or share them. • Fence Function: Give BuildCalc a fence row length and it will tell you how many posts, rails, pickets, and or panels you need. • Interactive Functions: The Stair, Baluster, Compound Miter, and Rafter functions are now fully interactive. Want to change input values? Change the Run? Switch between Regular and Irregular Hip Roof analysis? You can do this and your results will be updated automatically - without you needing to remember what key to press. MORE ANSWERS: • You are no longer tied down to: only one brick, block or tile size for the masonry function; a fixed number of drywall sheet sizes; only one footer cross sectional area; or one size of shingles and sheathing. If you don’t see the size you want, you can add as many as you need. And for area input, you can store your custom sizes in Length x Width format, so you won’t have to do mental gymnastics to figure out what was the dimensions for that last size you stored. • Want to cut your hip roof rafter using a miter saw ... or a circular saw using a hand-held protractor? With a tap of a button, BuildCalc will automatically switch between Miter Saw and Protractor results. BuildCalc can do this for Compound Miters, too. • Sheathing Angles, Purlin Angles, Gable Area, Backing Angles, Plan Angles, Rough vs. Finished Stair Layout Dimensions, Stringer Throat, Stringer installation dimensions ... and a lot more not found on other construction calculators. LESS COMPLEXITY AND LESS HASSLE: • Tired of having to press and press and press buttons to get the results of a calculation? BuildCalc puts an end to this. For all advanced functions, you get ALL of your results in list form with just one or two key taps. • And, rather than having to write down those results, all advanced functions allow you to save your results - as many times as you want with a label you choose - so you can recall the complete results at your convenience. Now you can do a calculation today and two days, two weeks or two years later, it is there for you. • Less “quirks”. Have you been annoyed by arcane key stroke sequences on other construction calculators? We are too. BuildCalc 2.1 streamlined the keystrokes to do a better job of giving you less “errors” and more results. Don’t remember what you have to enter before a Hip Rafter or Stair calculation? Well, now you don’t have to. BuildCalc will provide you with a check list of inputs and on-the-spot help to get it right. • Drywall and Masonry “Room Mode”: If you have stored a Length, Width and Height for a room, BuildCalc will give you the Drywall or Masonry required for the walls and the ceiling / floor - with only a tap of the Drywall or Masonry button. No more pondering over complex key sequences ... it just works. NOW WITH ADVANCED STAIRS, BALUSTER, AND HIP/VALLEY FUNCTIONS Get more results than you ever could before - including dimensioned Stringer, Stringer Installation and Finished Staircase Drawings. Drawings can then be emailed to others or printed at your convenience. Email us and we'll send you an example!

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Screenshots

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Build scope

Plan a focused first version with your coding agent. These are planning assumptions, not a delivery guarantee.

Define the first version

Choose one audience and one core workflow. Use the kit to agree on its screens, data, and acceptance criteria before building.

Set boundaries

Decide which secondary features, integrations, and platform support can wait. Your version does not need to reproduce everything in the original.

Check the hard parts

Validate external services, specialist technology, data access, and ongoing costs for your chosen scope.

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BUILD KIT DIFFICULTY
Intermediate

From the Build Kit assessment.

A reliable timeline needs an agreed scope and a technical check. Ask your agent to estimate the phases in BUILD_PLAN.md after that review.