Siding Estimator
Siding material takeoff by the square — gross wall less openings, trim sticks, corner posts, starter strip, fasteners, and labor.
≈21 sq ft/door, 15 sq ft/window
Vinyl: ~$220/sq. Hardie: ~$450/sq. LP SmartSide: ~$320/sq.
10% standard; 15% for gable-heavy elevations
Vinyl: ~40. Hardie: ~25. Wood: ~22.
Result
- Net wall area
- 1,520 sq ft
- Squares to order100 sq ft / square, 10% waste
- 16.75
- Trim sticks (10 ft)
- 25
- Corner posts
- 4
- Fastener boxes
- 3
- Siding cost
- $3,685
- Trim cost
- $450
- Corner cost
- $112
- Fasteners
- $195
- Starter / J-channel
- $102
- Material total
- $4,544
- Labor
- $2,090
- Total (material + labor)
- $6,634
This estimate is based on national average costs and may vary by region, project specifics, and market conditions. Use as a starting point for your bids.
How to estimate a siding job
Siding is sold by the "square" — 100 sq ft of coverage. The math is gross exterior wall area, minus openings, plus 10–15% waste, divided by 100. The trim and accessory line items are where bids drift. This calculator handles all the takeoffs in one pass.
Pricing benchmarks
| Material | Installed $/sq ft | Production rate |
|---|---|---|
| Vinyl (D4 / D5) | $4–7 | 3–4 squares/day/2-person |
| Fiber cement (Hardie) | $7–13 | 1.5–2 squares/day/2-person |
| LP SmartSide | $6–10 | 2–3 squares/day/2-person |
| Wood lap (cedar) | $8–15 | 1.5–2 squares/day/2-person |
Trim — the line items most takeoffs miss
Per-opening trim rules of thumb:
- Each window: 16–24 LF J-channel + corner trim
- Each door: 24 LF
- Each outside corner: 2 corner posts × wall height
- Each inside corner: 1 J-channel × wall height
- Starter strip: 1 LF per LF of bottom of wall
Add 10% to total trim for cuts. Trim is roughly 8–12% of total material cost on a typical residential re-side — easy to underbid.
Tear-off vs layer-over
Tear-off adds about 0.5 day per 1,000 sq ft of wall for a two-person crew, plus disposal. A 20-yard dumpster runs $400–650 in most markets and holds about 2,500 sq ft of old siding. Most reputable installers won't layer over wood or fiber cement — it hides rot and traps moisture. Layering vinyl on vinyl is sometimes acceptable if the substrate is sound.
Frequently asked questions
How is siding measured and ordered?
Siding is sold by the 'square' — 100 sq ft of coverage. Calculate gross exterior wall area, subtract doors and windows, add 10% waste, then convert to squares (divide by 100). Most distributors sell to the next quarter-square so a 12.6-square job is ordered as 12.75 squares.
What's a normal waste factor for siding?
10% for vinyl on a typical rectangular two-story. 12–15% for gable-heavy elevations (lots of diagonal cuts). 15%+ for fiber cement or LP SmartSide where cuts can't be reused as effectively. On true rectangle barns or sheds, you can get away with 7%.
How much trim do I need?
Each window typically needs 16–24 LF of J-channel + corner trim. Each door needs 24 LF. Each outside corner needs 2 corner posts × wall height. Inside corners need 1 J-channel × wall height. Add 10% to total trim for cuts. The calculator above takes a trim total LF — measure carefully and use the typical-per-opening numbers above.
Vinyl vs fiber cement vs LP SmartSide — installed cost?
Vinyl: $4–7 per sq ft installed. Fiber cement (HardiePlank): $7–13 per sq ft installed. LP SmartSide (engineered wood): $6–10 per sq ft installed. Vinyl is faster (~3–4 squares/day/2-person crew); fiber cement is slower (1.5–2 squares/day) because cuts require diamond blades and the boards are heavier.
Do I need to remove the old siding first?
On vinyl-to-vinyl: usually no, you can layer over if the substrate is sound. On wood-to-wood or any conversion: yes, full tear-off. Layering over hides rot and traps moisture — most reputable installers won't do it. Tear-off adds about 0.5 day per 1,000 sq ft for two people, plus disposal cost (a 20-yard dumpster runs $400–650 most markets).
Related calculators
Waste Factor
NewCalculate trade-specific waste percentages so you order enough material without over-buying.
Crew-Day Cost
NewCalculate the daily cost of a crew including burdened labor, vehicle, fuel, and jobsite overhead.
Labor Burden
NewConvert a wage rate into a true burdened cost including taxes, insurance, workers comp, and PTO.