PROJECTMETER
Calculators/Siding

Siding Calculator

Estimate vinyl siding squares for straight exterior walls after door and window deductions.

Free · No signup · Reviewed August 22, 2026
Step 1
Set your project size

Use the finished area you plan to cover, then refine the assumptions below.

Step 2 · Visual referenceCheck the active area
Residential exterior siding project reference
Gross face270 ft²Openings36 ft²Net face234 ft²

Why it mattersSee gross wall face, opening deductions and net siding area.

Reference image; figures update from your measurements.

You’ll need

3 siding squares
Shopping list
3100 sq ft siding squares
257.4sq ft including waste
234sq ft net wall
1 wall$555.00 primary material estimate

Project shopping list

Use your result as a starting point, then confirm package coverage, product instructions and local requirements before purchasing.

MaterialSidingPackage100 sq ft squareAllowanceIncluded

How the calculation works

net wall area × (1 + waste) ÷ 100

Enter each project area, choose the measurement system, then adjust waste and real package coverage. Packaged materials round up so the shopping list never suggests part of a box, sheet or panel.

MEASURE WITH CONFIDENCE

How to use the siding calculator

Measure each straight exterior wall, subtract doors and large windows, then add a practical cutting allowance. ProjectMeter converts the net coverage into 100-square-foot siding squares and rounds the order up to complete squares.

Formula and guidance reviewed August 22, 2026. Always confirm the final order with product instructions and project requirements.
STEP BY STEP

What to measure

  1. 01

    Measure one wall face at a time

    Record the horizontal wall length and the siding height from the lower start line to the top of the wall. Calculate gables, dormers, returns and walls with different heights as separate sections so the geometry stays visible and checkable.

  2. 02

    Deduct major openings

    Count normal doors and large windows to remove their planning area. Small vents and utility penetrations are usually better covered by the waste allowance because cutting around them still consumes material.

  3. 03

    Confirm the package coverage

    Vinyl siding is commonly planned in squares, where one square covers 100 square feet. Check the carton label because pieces per carton, panel exposure and cartons per square vary by product.

  4. 04

    Add cuts and layout waste

    Corners, window returns, starter-course cuts, short wall ends and damaged panels create waste. Begin with the displayed allowance, then increase it for complex elevations or unusual panel layouts.

WORKED EXAMPLE

30 × 9 ft wall with one door and one window

  • 270 sq ft gross wall
  • 36 sq ft standard opening deduction
  • 234 sq ft net siding area
  • 10% cutting allowance
Calculated result

The purchase coverage is 257.4 sq ft. Since siding is ordered in 100 sq ft squares, the shopping estimate rounds up to 3 complete squares.

Try your own measurements ↑
AVOID COSTLY REWORK

Common mistakes before you buy

  • Order matching starter strip, inside and outside corners, J-channel, utility trim, flashing and fasteners separately; these are linear or piece-count accessories, not square coverage.
  • Confirm panel exposure and overlap from the exact manufacturer instructions before converting the estimate into cartons.
  • Keep color-sensitive material from one production lot where possible and retain spare matching panels for future repairs.
FROM QUANTITY TO BUDGET

Compare the complete project cost

Your material quantity is only one part of a quote. Preparation, removal, access, finishing and local labour can change the installed total.

Replace siding$3–$30+ per sq ftEstimate siding by net wall area while accounting for material, stories, openings, trim, removal and weather barrier.Read cost guide →Install fiber cement siding$6,586–$23,207Estimate fiber cement siding by net wall area, profile, stories, removal, weather barrier, trim, finishing and access.Read cost guide →
MEASURE BEFORE YOU ORDER

Planning guides for this calculator

Use the live model for feedback, then use these guides to verify the dimensions and material assumptions behind the result.

Measure & estimateHow to Measure SidingMeasure wall planes, gables and openings for siding squares while keeping trim and accessories as separate linear quantities.Read guide →Choose & planSiding Waste, Trim and OpeningsSet siding overage from wall geometry and count starter, corners and opening channels without scaling the trim with wall area.Read guide →Compare materialsVinyl vs Fiber Cement vs Engineered Wood SidingCompare siding systems by weight, finishing, movement, impact, fire considerations, water details and maintenance.Read guide →Specify & buyLap Siding Profile and Exposure GuideChoose lap profile and visible exposure while keeping wall scale, fastening zones, joints and package coverage consistent.Read guide →Plan a projectGable Siding Layout PlanningCalculate triangular gable area and lay out courses, angled cuts, trim and access separately from rectangular walls.Read guide →Avoid failuresHow to Prevent Vinyl Siding Buckling and Water IntrusionPreserve panel movement and wall drainage through fastening, clearances, flashing and compatible accessory details.Read guide →Time the workVinyl Siding Temperature and Expansion PlanningSet fastening and clearances for actual panel temperature and product instructions.Read guide →Protect & maintainSiding Delivery, Storage and StagingProtect long panels and trim from heat distortion, crushing and mixed colour lots.Read guide →Manage the projectSiding replacement: Budget, Quotes, Safety and CloseoutManage a complete siding replacement project from measured quantity and comparable bids through safety checks, maintenance records and final acceptance.Read guide →Worked exampleSiding for a 40 × 30 One-Story HouseEstimate field siding for 9 ft walls and two 30 ft gables at 4:12 pitch after 180 sq ft of openings.Read guide →Worked exampleSiding for a 30 × 40 Two-Story HouseCalculate illustrative field squares for 18 ft wall height, two gables and 300 sq ft of openings.Read guide →Worked exampleCan You Estimate Siding from a 1,500 Sq Ft House?Show why floor area is insufficient for a siding order and identify the exterior measurements that replace it.Read guide →
TAKE THE PLAN TO THE SITE

Interactive project checklists

Use the pre-order list before material arrives, then save the inspection and maintenance list for closeout and future care.

SIDING · READYSiding Order and Installation ChecklistVerify wall areas, profile exposure, trim, flashing and movement details before panels arrive.Open 12-task checklist →SIDING · CARESiding and Flashing Inspection ChecklistInspect panel movement, openings, roof-wall transitions and drainage before cosmetic repairs.Open 12-task checklist →
COMMON QUESTIONS

Siding calculator FAQ

What is one square of siding?

One siding square is a coverage unit equal to 100 square feet of installed wall area. The number of cartons required for one square depends on the selected product.

Should I subtract every window and vent?

Subtract normal doors and larger windows. For small penetrations, the saved field area may be offset by surrounding cuts, so leaving them inside the measured wall and using a suitable waste allowance is often more practical.

Does the estimate include trim and housewrap?

No. Starter strip, corner posts, channels, flashing, housewrap, insulation, fasteners and specialty trim require separate measurements and product-specific installation details.

KEEP PLANNING
Roofing CalculatorEstimate pitched-roof area, roofing squares, shingle bundles and underlayment rolls.Brick CalculatorEstimate complete bricks for a straight wall after door and window openings, unit rate and waste.Fence CalculatorPlan panels, posts, gates, caps, concrete and a full material cost for straight runs.

Plan accurately. Build safely.

This calculator is a planning estimate, not engineering or code approval. Follow manufacturer instructions and consult a qualified professional for structural, electrical, gas or permit-sensitive work.