Free calculator
Build vs Buy Calculator
Compare the all-in cost of building a new home on a lot with buying a comparable existing home.
Difference
Building costs $136,600 more
35.4% · build $244/sq ft · buy $180/sq ft · 14 months longer when building
Building matches buying at about $104/sq ft hard cost.
Build all-in $522,600. Buy all-in $386,000. Buy cost scaled to the size you would build: $386,000.
| Item | Amount |
|---|---|
| Build | $522,600 |
| Buy | $386,000 |
| Build | Amount | Buy | Amount |
|---|---|---|---|
| Lot | $60,000 | Price | $350,000 |
| Hard cost | $339,301 | Closing | $8,750 |
| Site work | $15,000 | Inspections | $500 |
| Fees | $16,286 | Repairs | $10,000 |
| Design | $5,090 | 10-year maintenance gap | $15,000 |
| Contingency | $35,430 | Rent while waiting | $1,703 |
| Carry | $19,900 | ||
| Closing | $6,000 | ||
| Rent while waiting | $25,545 | ||
| All-in build | $522,600 | All-in buy | $386,000 |
The buy-side defaults are placeholders. Replace them with local listings.
Results link:
With the defaults, build is a $60,000 lot + $339,301 hard + $15,000 site + $16,286 fees + $5,090 design + $35,430 contingency + $19,900 carry + $6,000 closing + $25,545 rent, for a total of about $522,600 ($244 per sq ft). Buy is $350,000 + $8,750 closing + $500 + $10,000 + $15,000 + $1,703 rent, for a total of about $386,000 ($180 per sq ft). Under these placeholder inputs, building costs about $136,600 (35%) more and takes 14 more months. The two sides match at a hard-cost rate of about $104 per sq ft. The buy-side defaults are placeholders, so replace them with real local listings.
How this is calculated
hard = build_psf * sqft
fees = hard * fees_pct/100
design = hard * design_pct/100
contingency = (hard + site_work) * contingency_pct/100
rent_build = rent_monthly * months_to_move_in
total_build = lot_price + hard + site_work + fees + design + contingency
+ carry_cost + build_closing + rent_build
rent_buy = rent_monthly * months_to_close
total_buy = buy_price * (1 + buy_closing_pct/100) + inspection + repairs
+ maint_gap_10yr + rent_buy
difference = total_build - total_buy
difference_pct = difference / total_buy * 100
build_all_in_psf = total_build / sqft
buy_all_in_psf = total_buy / buy_sqft
buy_size_adj = buy_all_in_psf * sqft
extra_months = months_to_move_in - months_to_close
fixed_build = lot_price + site_work*(1 + contingency_pct/100) + carry_cost
+ build_closing + rent_build
breakeven_psf = (total_buy - fixed_build) / (sqft * (1 + (fees_pct + design_pct + contingency_pct)/100))
A positive difference means building costs more under these inputs. The math counts costs only. It does not forecast values or appreciation.Default values and sources
| Default | Value | Status | Source | Notes |
|---|---|---|---|---|
| Rent while you wait | $1,703 per month | Sourced | HUD FY2027 Fair Market Rent, 3-bedroom, Yuma AZ MSA | Yuma County. Enter 0 if your current housing cost does not change. |
| Living area | 2,142 sq ft | Sourced | Census Characteristics of New Housing, 2025 | Median completed single-family home. The buy-side size starts at the same number so the comparison is like for like. |
| Fees and design | 4.8% and 1.5% | Sourced | NAHB Cost of Constructing a Home 2024, Table 1 | National averages for permits, impact fees, utility connections, and architecture and engineering. |
| Hard cost per living sq ft | $158 | Derived | New-build cost estimator, Yuma County defaults | $169 Mountain-division median times the 0.85 Yuma factor, plus a garage at 50% of that rate, divided by living area. The county cap and garage share are assumptions. The live default keeps the unrounded rate so the hard cost matches the estimator's $339,301. |
| Months to move in | 15 | Derived | Census construction time, plus an assumed pre-build | 12 of the 15 months round the 11.7-month hired-contractor build. The other 3 months are an assumption for design and permitting. |
| Carry cost | $19,900 | Derived | Lot carry cost calculator defaults | Rounded total from that calculator's mix of sourced and assumed inputs. |
| Lot price | $60,000 | Editable assumption | No public source verified | Replace with your lot. |
| Site work | $15,000 | Editable assumption | No public source verified | City utilities placeholder. Replace with quotes. |
| Contingency | 10% of hard cost + site work | Editable assumption | No public source verified | Same treatment as the cost estimator. |
| Lot and construction closing | $6,000 | Editable assumption | No public source verified | Title, escrow, and lender fees. |
| Comparable home price | $350,000 | Editable assumption | No public source verified | Placeholder. Enter a local comparable of similar size and features. |
| Buyer closing costs | 2.5% of price | Editable assumption | No public source verified | Replace with your loan estimate. |
| Inspections | $500 | Editable assumption | No public source verified | Placeholder. |
| Repairs at move-in | $10,000 | Editable assumption | No public source verified | Placeholder for immediate work on an existing home. |
| Extra maintenance over 10 years | $15,000 | Editable assumption | No public source verified | Roof, HVAC, water heater, and similar items compared with a new home. |
| Months from offer to move-in | 1 | Editable assumption | No public source verified | You can change it. |
Sources last verified: 2026-10-18. Re-verify every source at least yearly.
How the comparison is built
What this calculator compares
Do you build on a lot or buy an existing home? The answer depends on the whole cost stack, not just the price tag. This calculator adds up everything you'd spend to get to move-in day on each path, side by side. It doesn't predict home values, resale, or appreciation. It only counts costs.
The build side
Building starts with the lot, then the house. The default hard-cost rate comes from the New-Build Cost Estimator Yuma County figure. It's based on the 2024 Census median for contractor-built homes in the Mountain region, adjusted by county and including a garage. Next come site work and utilities, permit and impact fees, and design. Then there's a contingency, because no build goes exactly to plan.
Two lines people often forget are carry and rent. Carry covers property tax, insurance, and construction-loan interest while the house goes up. The Lot Carry Cost Calculator can supply that figure. Rent is whatever you pay to live somewhere else from lot purchase to move-in, often more than a year once you count design and permitting. The default rent is HUD's Fair Market Rent for a three-bedroom home in Yuma County.
The buy side
Buying looks simpler, and in time it is: you usually move in within weeks. But a fair comparison adds closing costs, inspections, the repairs or updates most existing homes need right away, and a realistic estimate of extra maintenance over the next ten years. A 15-year-old roof, HVAC system, or water heater will come due sooner in an existing home than in a new one. The buy-side defaults are placeholders. Pull a few real listings of similar size and age in your area before you trust the result.
Reading the result
There are three numbers to look at. The difference tells you which path costs more under your inputs, in dollars and percent. The all-in cost per square foot for each side normalizes for size, so a 2,100 sq ft new build and a 1,800 sq ft resale can be compared fairly. The break-even hard-cost rate tells you how low the build cost per square foot would need to be for the two paths to cost the same. If a local builder's bid comes in near that number, the paths are close. If it's far above, buying costs less under your inputs.
What it leaves out
The math doesn't cover what each path gets you that isn't a cost: a floor plan built for you, newer energy codes and warranties, or the convenience of moving in sooner. It also leaves out mortgage costs after move-in, which depend on your loan. Those are judgment calls. The calculator just makes sure the costs are counted on both sides.
You can refine the build cost, calculate carry precisely, or check the build timeline. Related writing: build vs buy articles.
Questions
Is it cheaper to build or buy a house in Arizona?
It depends on local lot prices, build costs, and what comparable homes sell for, so no single rule applies statewide. Building often costs more up front once you count site work, fees, carry, and rent during construction. But a new home can need fewer repairs for years. Enter local numbers in this calculator to see which costs less in your case.
What costs do people forget when comparing building and buying?
The ones people miss most are rent or other housing costs during design, permitting, and construction; construction-loan interest and property tax while the house is going up; and site work for utilities, septic, or a well. On the buy side, people forget immediate repairs and higher maintenance on older systems such as the roof and HVAC.
How long does it take to build instead of buy?
Census data shows homes built by hired contractors took about 11.7 months from permit to completion in 2025. Add design and permitting before that, often 2–4 months, and you're past a year. Buying an existing home is usually much faster. The calculator assumes one month from offer to move-in (you can change it) and charges rent for every month of the difference.
What is the break-even build cost per square foot?
It's the hard-construction cost per square foot at which building and buying cost the same, given everything else you entered. If local builders quote below that rate, building comes out cheaper under your inputs. If they quote above it, buying does. It's a quick way to judge whether a builder's bid is in range for your situation.
Does this calculator predict home values or appreciation?
No. It compares the costs of reaching move-in day on two paths, plus an optional ten-year maintenance difference. It doesn't forecast market values, resale prices, appreciation, or financing after move-in. It's an educational cost tool, not financial advice. Check major decisions with a licensed lender, agent, or advisor.
Educational cost comparison only. This isn't financial, real estate, or lending advice, and it doesn't project values or appreciation. Defaults marked as assumptions are placeholders. Replace them with local figures.