Free App

Free construction calculators
that respect your time.

Concrete, framing, rafters, roofs, balusters, decks, and drywall — built for carpenters, roofers, and serious DIY. No ads, no signup, and every formula is shown on the page so you can check the math. Start in the browser, then take the free Android app to the jobsite for offline use, voice input, and material lists.

Free web tools Open calculators No signup. Instant estimates in the browser. Free Android app Get the Free App Offline, voice input, material lists, PDF export/share.
No ads. No signup. No paywall.
Human-checked formulas, shown on every page — not AI guesses.
Metric and imperial, auto-detected by your region.
Built for the trades: concrete, framing, rafters, decks, roofs.

Calculators

Start-to-finish flow

VibeCalc is meant to feel like one tool belt: quick browser math first, then a jobsite app path when the estimate turns into a material run.

Choose a calculator
  1. 1

    Pick the job

    Start from the calculator grid, filter by trade, or tap a shortcut for cost, materials, decks, roofs, or framing.

  2. 2

    Enter real measurements

    Use the units you already have. Inputs are big, touch-friendly, and built for jobsite notes.

  3. 3

    Read the takeoff

    Results update instantly with waste, packs, boards, bags, bundles, or cost lines where the math supports it.

  4. 4

    Move to the app when needed

    Keep the web version free for quick checks; use Android for offline work, voice input, material lists, and PDF export/share.

Fastest-moving calculators

Jump straight into the clusters showing the clearest early search demand: baluster / spindle / stair railing spacing and wall stud counts.

Open stud calc
High-signal

Baluster & Spindle Spacing Calculator

Current strongest early signal: deck baluster, spindle, stair railing, and 4 inch sphere spacing.

 High-signal

Stud Calc / Wall Stud Calculator

Closest first-page candidate: wall stud counts at 16 inch, 24 inch, 400mm, and 600mm spacing.

 High-signal

Baluster Spacing Template

Common 4 ft, 6 ft, 8 ft, 10 ft, stair railing, and metric spindle spacing templates.

 High-signal

Baluster Spacing Code

4 inch sphere rule, 100 mm metric rule, stair railing gap notes, and calculator links.

Popular material estimators

Guide

Deck Board Calculator

Board count, rows, and linear footage from deck size, board width, gap, and waste.

 Guide

Drywall Calculator

Sheets of drywall for any wall and ceiling area — 4×8, 4×12, or metric boards, with waste.

 Guide

Concrete Bag Calculator

Quick bag-count estimates for 80lb, 60lb, 25kg, and 20kg concrete bags.

 Guide

Stud Count Calculator

Wall framing stud counts for 16 inch, 24 inch, 400mm, and 600mm spacing.

 Guide

Drywall Sheet Calculator

Sheet counts for 4×8 sheets, 4×10, 4×12, metric boards, and waste.

 Guide

Rafter Length by Pitch Calculator

Rafter length by roof pitch, run, rise, and slope angle.

 Guide

Baluster Spacing Template

Common deck, stair, and spindle layouts with even gap templates.

 Guide

Deck Railing Post Spacing Calculator

Post count and even section spacing before baluster or spindle layout.

 Guide

Baluster Spacing Code

4 inch sphere rule, 100 mm spacing, and code-safe railing gaps.

 Guide

Wall Framing with Doors & Windows

Plan king studs, jack studs, headers, sills, and cripple studs around openings.

 Guide

Ridge Height Calculator

Calculate roof ridge height from span, run, and pitch.

 Guide

Roof Overhang Calculator

Estimate sloped rafter tail length from horizontal eave overhang and pitch.

 Guide

Valley Rafter Calculator

Estimate valley rafter length from run and roof pitch for square roof corners.

 Guide

Rafter Cut Calculator

Plan birdsmouth cuts, plumb cuts, rafter angles, and tail layout before cutting.

 Guide

Lean-To Rafter Calculator

Estimate shed roof and single-slope rafter length from run and pitch.

 Guide

Rake Wall Calculator

Plan gable wall framing, rake wall height changes, and stud layout from roof pitch.

What you get

Live
Calculations update as you type - no "calculate" button.
Mobile
Built for phones first. Use it standing on site.
Auto unit
Imperial in the US, metric everywhere else. Detected from your browser.
Cost
Specific cost estimators where the math is bounded: material + labor, not generic bid software.
VibeCalc Android app icon
Android App

Take VibeCalc to the jobsite

Essential offline calculators for Android. Voice-controlled, no signal needed. Free, no ads, no accounts.

Get the Free App Free. Built for Android phones. Donations welcome.

Saved you a mistake? Support VibeCalc

Built by builders

VibeCalc started as an Android app for tradespeople doing the same arithmetic on every job: slab volumes, stud counts, rafter lengths, baluster spacing, material counts, and early cost estimates. The web version puts the same formulas in a browser tab.

Concrete by L × W × T or π × r² × h. Studs by length over on-center spacing plus the end stud. Rafters by Pythagoras minus the ridge plumb-cut. Balusters by gap distribution under code limits. Fence costs by sections, posts, gates, waste, and labor. The math is real, the formulas are open, the answers update as you type.

Math you can check

AI chatbots fumble everyday math — independent testing found the leading models are right only 45–63% of the time. VibeCalc isn't AI: every calculator runs a fixed, human-written formula that's printed right on the page and returns the same answer every time.

AI vs. construction math

Common questions

Is VibeCalc free to use?
Yes. The VibeCalc website is free to use for concrete, framing, rafters, roof pitch, balusters, deck boards, stair stringers, drywall, insulation, paint, tile, shingles, fence cost, excavation cost, and labor cost estimates. No signup or email is required.
What construction calculators are included?
VibeCalc includes free calculators for concrete volume and bags, wall framing stud counts, rafter length, roof pitch, baluster spacing, deck boards, stair stringers, drywall sheets, insulation packs, paint, tile, roof shingles, fence cost, excavation volume/cost, and labor cost estimating.
Does VibeCalc work with metric and imperial units?
Yes. The web calculators support metric and imperial workflows, and the site auto-detects a sensible starting unit system from your browser region.
Why get the Android app if the web calculators are free?
The web calculators stay open in your browser. The free Android app adds the jobsite workflow: offline use, voice input, shopping-cart style material lists, and PDF export/share. Both are free, no ads, no accounts.
Can I just ask an AI chatbot to do the construction math?
You can, but independent testing (the ORCA benchmark) found leading AI chatbots get everyday math right only about 45–63% of the time, with frequent rounding and calculation slips — and they sometimes give different answers to the same question. VibeCalc is not AI: every calculator runs a fixed, human-checked construction formula that returns the same answer every time and shows that formula on the page. See the VibeCalc note on AI vs. construction math for details.

Disclaimer

VibeCalc provides free construction calculators for estimation purposes only. Calculations are based on standard construction formulas and do not account for site-specific conditions, local building codes, soil-bearing capacity, environmental factors, or material variations.

These calculators are not a substitute for professional engineering, architectural, or contracting advice. For any load-bearing structure, foundation, roof framing, guardrail, or other safety-critical work, you must consult a licensed structural engineer or qualified contractor and comply with your local building codes and permit requirements.

You are solely responsible for verifying all measurements, material specifications, applicable building codes, and the suitability of any calculator output for your specific project.

To the maximum extent permitted by law, VibeCalc, its operators, contributors, and licensors disclaim all warranties (express or implied) and all liability for any errors, omissions, inaccuracies, property damage, personal injury, financial loss, or other damages arising from or related to use of these calculators or reliance on their output.

By using VibeCalc you acknowledge that you have read, understood, and accepted this disclaimer and that you assume all risk associated with your use of the site and any decisions made based on its output.