Construction Cost Calculator

What does a construction cost calculator count?

It counts a whole building job as one stack of money, before anyone writes a bid. Four jobs share the card: a single-family house from its footprint, an apartment block from its unit count, a warehouse shell from footprint and ceiling height, and a remodel with or without an addition.

Every tab ends at the same place: an area, a hard cost for it, and the money that rides on top — 9% soft costs, a 15% builder fee on hard plus soft, and your contingency, opening at 10%. The headline is the all-in planning budget. The case this page follows — a 40 × 25 ft two-story, 2,000 sq ft, standard finishes, national prices — reads $592,906, at $296.45 a square foot, over 7 months.

How does the calculator work?

Pick the building tab, fill its boxes, and read the right-hand column top to bottom. The headline is the total with the buffer in it. Under it: the all-in rate per square foot and the gross area counted — check that area first, because every dollar hangs off it. Then hard cost alone, schedule in months, and the trade split.

Tier, location and contingency sit above the tabs and apply to all four; switching tabs swaps only the area boxes.

How do you calculate construction cost?

One multiplication builds the area; the next stacks the money.

Run the stack on the house this page follows: 2,000 sq ft at $215 is $430,000 hard; soft costs make $468,700; the builder fee makes $539,005; 10% contingency closes at $592,906. The tier’s $215 is the starting rate for the work; the $296.45 under the headline is a square foot with the whole stack on it.

3 worked examples

How much does it cost to build a 2,000 sq ft house?

At standard finishes and national prices, $592,906 — no garage, default 10% contingency. Living area prices at one flat rate, so sizes around it scale in a straight line at $296.45 a foot:

Standard $215, national factor, 10% contingency, no garage. The straight line is the card’s honesty and its limit: a real 1,200 sq ft house usually costs more a foot than a 3,000 sq ft one — kitchens and baths do not shrink with the box.

What does another story do to the budget?

Stories multiply the footprint into living area — nothing else moves. One 50 × 30 ft footprint, four houses:

Type the footprint once and let the menu multiply; a 3,000 sq ft house typed as one 100 × 30 story prices the same area but says nothing about the foundation you dig. Stories never multiply the garage.

The 1.5 setting is for an upper floor genuinely half the footprint — a Cape with dormers. Wall to wall upstairs is a 2.

The garage and the porch are area at a discount

Unfinished and covered-outdoor space should not cost living-space money: the garage prices at 45% of the base rate, a covered porch at 35% — $96.75 and $75.25 a square foot at the standard tier, before the stack.

The garage opens at none and the porch box empty — both count only what you ask for. An uncovered deck you frame yourself belongs on the deck calculator, not in the porch box.

Watch the headline rate when you add them: the 2,000 sq ft house with a 2-car garage and 180 sq ft porch climbs to $675,616, yet the rate *drops* to $253.99 a square foot — gross area grew to 2,660 sq ft with cheaper feet. A falling rate on a rising total is the card working as designed.

Why does the budget carry a contingency?

Because the ground, the lumber market and the owners all change their minds. The menu runs 5% for a fixed scope, 10% standard, 15% for custom work and additions, 20% when prices or the building are volatile. No 0% exists here; the smallest cushion is 5%.

The reserve is a percent of hard + soft + fee combined, not hard cost alone — 10% here is $53,901, not $43,000. The row under the results restates your pick.

Apartments: units, corridors and the floors menu

The multi-family tab never asks for a footprint. It builds gross area from the units, then grosses up for corridors and stairs nobody rents: units × average size × (1 + common %). Eight 950 sq ft units is 7,600 sq ft of apartments; the common-area menu decides the building around them.

Standard tier, national factor, 10% contingency. Five points of corridor on this block is 380 sq ft and about $113,000.

The floors menu is the trap here. The unit count already holds every floor’s apartments, so the menu holds only the calendar: this block schedules 10 months over 2 floors, 12 over 3, 16 over 5 — at the identical $2,590,997.

Warehouses, mezzanines and tall ceilings

The commercial tab is a footprint with two knobs. The mezzanine adds area at the full rate. Clear height adds nothing until it passes 16 ft; past that, each extra foot adds a flat $1,200 to hard cost — a stand-in for taller walls, not a steel takeoff.

Standard tier, national factor, 10% contingency. The height money ($2,400 at 18 ft, $9,600 at 24 ft) sits inside hard cost, so the stack compounds on it; location never touches it. The floor slab is its own pour, sized on the concrete slab calculator.

The tier list still describes house finishes, so a warehouse at standard reads as finished space. A bare shell wants economy, or your own rate typed over it.

What does the total actually include?

Four layers, always in the same order. On the 2,000 sq ft house they read:

The trade rows split the hard layer only: site 13%, framing 21%, envelope 16%, MEP 19%, finishes 18% — 87% of hard cost, the rest unallocated, with soft + fee and the reserve as their own rows. As the card says: planning splits, not a bid.

The base rate comes from the finish tier, unless you type over it:

The all-in column is the base rate with the default stack on it (×1.09 ×1.15 ×1.10), living area only, no garage. The tier menu also prints a $/m² beside each rate for metric jobs.

What the cost line does not include

• The land. Lot, closing costs, survey — none enter the card.
• Getting utilities to the lot. Well or water meter, septic or sewer tap, power drop. The tip under the results flags these on raw land as a five-figure line of their own; the total assumes services at the street.
• Site work beyond the building. Long driveways, retaining walls, clearing, rock, landscaping. The 13% site row is an average slice of hard cost, not a promise about your dirt.
• Financing and carrying costs. Loan interest, insurance riders, rent while you wait — the stack never sees them.
• Anything bought separately. Appliances beyond the tier, furniture, and the uncovered patio left out of the porch box.
• A basement you did not count. There is no basement box; finished basement space enters as footprint and stories, or not at all — its footings are sized on the concrete footing calculator.

Hard cost, all-in cost and the number a builder quotes

This card prints two of the three numbers called “the price” on a build. The base rate ($215 standard) is the brochure number: hard cost a foot at national prices. The all-in rate ($296.45) is that foot with the stack on it. A builder’s quote — specific subs, allowances, lot — is the third.

Location moves the first number before the stack starts — the same house, five ways:

The factor multiplies hard cost only; the stack compounds on the result — a 1.25× city adds about $148,000, not $107,500. It never scales the warehouse height allowance.

Have a better local number — a builder’s ballpark, a comparable build? Type it into the override and it replaces the tier rate outright: $250 over the $215 tier reads $500,000 hard and $689,425 all-in on this house. A 0 or an empty box is ignored; the tier stands.

How do you enter metres and square metres?

Tap Metric: footprint boxes take metres, area boxes (porch, unit size, mezzanine, remodel) take square metres, the override takes $/m². Inside, areas convert to square feet and price at the same tier rates — the $2,314/m² beside the standard tier is $215 a foot restated.

A 12 × 8 m footprint at 2 stories is 192 m² of living area: $612,670, hard $444,334 — and the subline still leads with $296.45/sq ft • 2,067 sq ft Gross Area (192.0 m²), square feet first, even in metric. Type the $2,314/m² label rate as the override and it barely blinks, to $612,607.

The toggle converts nothing already typed: leave 40 × 25 in the boxes and it reads as a 1,000 m² footprint — a $6,381,976 house. Retype after switching.

Remodel, addition, or both — how deep is the job?

The remodel tab prices two animals in one run. New area is new construction at the full tier rate. Existing area is weighted by depth: 0.55 cosmetic (floors, paint, trim), 0.85 major overhaul (kitchen, bath, moved plumbing), 1.15 gut to the studs. The weighted area is what prints as gross, so the $/sq ft holds at the all-in rate while the area breathes.

Standard tier, national factor, 10% contingency. Either box stands alone: addition only $118,581; the 650 sq ft major remodel only $163,790 on a weighted 553 sq ft.

Read the menu by the walls: drywall and plumbing stay — cosmetic; fixtures and pipes move — major; studs showing — gut, costlier a foot than new work at 1.15.

What are the common mistakes on a building budget?

• Quoting the tier rate as the budget. $215 is hard cost; the planned check is $296.45 all-in on the same house.
• Typing living area as the footprint, then 2 stories. A 2,000 sq ft two-story is a 1,000 sq ft footprint × 2; type 2,000 as the footprint too and you budgeted 4,000 sq ft.
• A garage counted twice, or never. The menu is the only garage here; one drawn inside the footprint prices as living space.
• Expecting floors to stack an apartment block. Area is units × size. Floors move the months, never the dollars.
• Pricing a gut at cosmetic intensity. 0.55 is paint and floors. Moved plumbing is 0.85; studs showing is 1.15.
• Reading trade rows as a bid. Fixed percents over 87% of hard cost; a sub far off a row is a conversation, not an error.
• Typing 0 in the override to turn the tier off. Zero is ignored; the tier prices the job anyway.
• Metric with feet still in the boxes. The toggle converts nothing typed: 40 × 25 becomes a 2,000 m² house at $6,381,976.
• Trusting Reset to clear the menus. Typed boxes empty; tier, location, contingency restore. Stories, garage, common area, floors, intensity stay — check before the next run.

How this calculator counts

Every rule, as the card applies it:

• Areas: footprint × stories (1 / 1.5 / 2 / 3); units × size × (1 + common %); footprint + mezzanine; existing × intensity (0.55 / 0.85 / 1.15) + addition. No area typed reads all zeros, garage alone included.
• Rates: $140 / $215 / $320 / $460 per sq ft hard. A typed override replaces the tier; empty or 0 keeps it. Metric override per m², converted back per foot.
• Discounted area: garage 240 sq ft a car at 45% of rate; covered porch at 35%. Mezzanine and additions pay full rate.
• Tall ceilings: past 16 ft, $1,200 a foot into hard cost; location never scales it, the stack does.
• Location: 0.85 / 1.00 / 1.10 / 1.25 / 1.45 on the area-priced hard cost.
• The stack: soft 9% of hard; fee 15% of hard + soft; contingency 5 / 10 / 15 / 20% (no 0%) of the three combined — hard × 1.3789 at 10%.
• Trades: 13% site, 21% framing, 16% envelope, 19% MEP, 18% finishes — 87% of hard cost, rest unallocated; soft + fee and the reserve print separately.
• Schedule: 4 + area ÷ 600; apartments 6 + area ÷ 2,200 + 2 a floor past two; remodel 2 + weighted area ÷ 450. Whole months, held to 4–24 / 8–36 / 2–18.
• Rounding/units: whole dollars; rate two decimals; whole sq ft, m² one decimal (× 0.092903). Metric converts at input (× 10.7639); the subline leads with sq ft in both modes; the toggle converts nothing typed.
• Reset/copy: reset restores tier, location, contingency only; tab, unit and tab menus keep settings. Copy Result copies the estimate as text.

Frequently asked questions