Deck Calculator for a Second-Story Deck
Estimate materials for a second-story elevated deck.
Second-story decks carry the same live load as ground-level but need larger posts, deeper footings and a permit-inspected ledger connection to the house. Use 6×6 posts on 24 in-diameter concrete footings dug below the frost line, and never notch a post — bolt beams to the side face.
Deck boards
35
Joists
13
Screws
280
192 ft² deck
Save this project
Sign in to save calculations to your dashboard.
Download your PDF report & project guide
Your results and inputs, a printable shopping list, a step-by-step guide and pro tips — in one PDF.
Planning a whole project?
Get every calculator, a full shopping list and a budget template for:
Recommended tools & materials
Handy picks for this project on Amazon.
Speed Square
Fast angle and rafter layout
View on Amazon →
Framing Nailer
Drive framing nails in seconds
View on Amazon →
Construction Screws
Structural, coated, no pilot hole
View on Amazon →
25 ft Tape Measure
Durable, easy-to-read blade
View on Amazon →
As an Amazon Associate, MaterialCalc earns from qualifying purchases.
How does the deck calculator work?
Board count = (deck length ÷ board length) × (deck width in inches ÷ board actual width). A "5/4×6" board is really 5.5 in wide. Joists at 16 in on-center: (length in inches ÷ 16) + 1.
Which guide explains this in more depth?
- Riser-and-tread math plus 2026 material prices for a full stair build. Read the stair calculator cost breakdown guide for the full worked example.
What else do people ask about this calculator?
Do second-story decks need a permit?
Yes — any elevated deck needs a permit and inspection. Ledger board attachment to the house band joist is the most-cited code violation on DIY decks.
What size posts for a second-story deck?
6×6 pressure-treated posts on concrete footings poured to below the frost line. 4×4 posts are only code-legal for decks under 30 in from grade.
How many deck boards for a 16×12 deck?
At 12 ft boards and 5.5 in actual width, about 27 boards plus 10% waste — order 30.
How far apart should deck joists be?
16 in on-center for standard decking; 12 in for composite or for spans over 12 ft.
Which related calculators should I use next?
All calculators