Introduction
Posts and their footings are one of the biggest line items in a deck frame budget — the lumber is heavy, the concrete is heavier, and the hardware that ties it all together adds up fast. A realistic Deck Post Calculator estimate starts with accurate counts, and this cost guide turns those counts into dollars: typical US planning ranges for 4×4 and 6×6 lumber, concrete, connectors, and labor, the drivers that push costs up or down, and practical ways to keep the total in check. Prices below are typical 2026 US retail ranges and vary by region, so treat them as planning figures and confirm with your local supplier.
Post Lumber Costs: 4×4 vs 6×6
The single biggest cost lever is post size. A 6×6 contains roughly two and a half times the wood of a 4×4, costs more per linear foot, and is harder to find in long lengths — but for elevated decks it is the right call structurally, so do not downsize to save money.
| Post | Pressure-Treated (each) | Cedar (each) |
|---|---|---|
| 4×4 x 8 ft (2.44 m) | $12-$20 | $25-$40 |
| 4×4 x 10 ft (3.05 m) | $16-$26 | $32-$50 |
| 6×6 x 8 ft (2.44 m) | $28-$45 | $55-$85 |
| 6×6 x 10 ft (3.05 m) | $36-$55 | $70-$105 |
| 6×6 x 12 ft (3.66 m) | $45-$70 | $85-$130 |
Pressure-treated southern yellow pine is the default for structural posts because it is strong, widely available, and rated for ground contact. Cedar costs roughly double but resists rot naturally and looks better exposed — a reasonable choice for visible railing posts on a premium deck. Redwood runs similar to cedar where it is available regionally. Our material guide compares grades, species, and steel alternatives in depth.
Concrete and Footing Costs
Concrete is the line item most DIY estimators forget, and it is not cheap. An 80-lb (36 kg) bag of concrete mix typically runs $5-$8 and yields about 0.6 cubic feet (0.017 m^3). A standard 12-inch-diameter by 36-inch-deep footing (30.5 cm x 91 cm) needs about four bags — $20-$32 per footing just in bagged mix.
For larger jobs the math flips: once you pass roughly 1 to 1.5 cubic yards (0.76 to 1.15 m^3), ready-mix delivery at $150-$250 per cubic yard often beats bagged concrete on both price and labor. Eight 18-inch footings at 42 inches deep total about 1.8 cubic yards (1.4 m^3) — firmly in ready-mix territory. Add forming tubes ($8-$15 each for 12-inch tubes), a few bags of gravel for the footing base ($5-$7 per bag), and possibly a concrete vibrator rental if you are pouring deep piers.
Hardware and Connector Costs
Every post needs proper connectors, and inspectors check them. Budget per structural post: a galvanized post base ($8-$20), a beam-to-post cap or saddle ($8-$15), and through-bolts or structural screws ($3-$8 per connection). For six posts that is roughly $115-$260 in hardware alone. Stainless or heavy-duty coated hardware for coastal or high-moisture areas runs 30-50% more. Guardrail posts add rail connectors and tension ties where the code requires them — check the code compliance guide before buying.
Labor Costs
Hiring out changes the picture completely. A contractor typically charges $200-$400 per post installed — including digging or augering, setting forms, pouring concrete, and setting the post plumb. Footings below a deep frost line cost more because of the digging. As a rule of thumb, professional installation roughly doubles the materials cost of the post-and-footing package. Our DIY vs pro guide breaks down when the labor premium is worth paying.
What Drives the Total Up or Down
- Deck height. Taller decks need 6×6 posts in longer lengths, deeper footings, and often bracing — the post package can easily double versus a ground-level deck.
- Frost depth. A 48-inch-deep footing in Minnesota uses a third more concrete than a 24-inch footing in Texas, and the digging costs more too.
- Soil conditions. Soft or fill soils can require wider footings; rock means expensive excavation. Both show up as bigger numbers on the estimate.
- Post count. Every extra beam line or tighter spacing adds a post, a footing, a base, and a cap. Efficient beam layout — see the estimating guide — is a direct cost control.
- Species and grade. Cedar and redwood posts can double lumber cost versus pressure-treated pine; clear-grade stock adds more.
- Access. If a ready-mix truck or an auger cannot reach the site, labor hours climb fast.
How to Save Without Cutting Corners
First, finalize the layout before buying — every design change after the lumber order wastes money. Second, optimize beam placement: fewer, well-placed beams within code span limits mean fewer footings. Third, price bagged versus ready-mix concrete at your actual volume; the crossover surprises most people. Fourth, buy posts slightly long and trim on site rather than paying for exact custom cuts. Fifth, rent the auger and the mixer for a single day and pour all footings at once — mobilization is the expensive part. Finally, do not economize on connectors or footing size: those are the cheapest insurance in the whole project, and undersized footings are the most expensive mistake in the common mistakes guide.
Related Guides
- Deck Post Complete Guide — the flagship overview: inputs, formulas, a worked example, and the mistakes that distort results.
- Deck Post Material Guide — lumber species, pressure-treated grades, steel posts, and every connector compared.
- Deck Post Formulas Explained — how post counts, footing volumes, and post lengths are actually derived.
- DIY vs Hiring a Pro — where the labor money goes and when professional installation pays for itself.
- Deck Post Case Study — a fully costed hypothetical 16×20 ft deck with line items that add up exactly.
Get Your Number
Costs only mean something attached to quantities, so start with the count: run your dimensions through the Deck Post Calculator, multiply the resulting post, footing, and hardware counts by your local prices, and add a 10% contingency for waste and price movement. That gives you a budget you can defend at the lumberyard — and a baseline for comparing contractor bids line by line.
Disclaimer: Prices are typical US planning ranges and vary by region and over time; results are planning estimates only. Verify quantities and prices with your supplier and consult a licensed professional or your local building authority for structural or code-related decisions.
