Know how much paint to buy before you open a tin.
Paintable area, gallons and cost for walls, ceilings, trim, doors and exteriors, with coats, primer, surface porosity and openings taken off, plus a line you can put straight on a quote.
Surface
Length (ft)
Width (ft)
Height (ft)
Doors (21 sq ft each)
Windows (15 sq ft each)
Coats
Coverage (sq ft per gallon)
Price per gallon ($)
Labor rate ($ per sq ft)
Include ceiling?
Quick examples for invoices
Your paint estimate to invoice
Total to invoice - $100 paint + $300 labor
Formula text
Invoice line item template for painting
Line item
The same panel you used above, working out a 12 by 12 room, then the trim, then an exterior. The fields change with the surface, and so does the drawing.
Your paint order
0 gal
Gallons to buy
yd³ = L × W × T ÷ 27
If the surface is rough
Start with the amount you need to borrow
Jump to any part to replay it. The formulas behind these numbers are set out further down the page.
The volume is the easy part of a concrete job. These are the four places the money goes missing between working out the order and being paid for the pour.
Concrete is rarely half the finished cost. Excavation, hardcore, forms, mesh, labour and the finish are the rest, and a client who was quoted a yard price will argue about every one of them later.
Itemise it once on a written quote and the conversation is over before it starts.
The 10 percent you add for uneven subgrade and what stays in the drum is real money on a large pour. Price it in rather than absorbing it, and note on the quote that surplus concrete cannot be returned once it is batched.
The profit margin calculator checks the job still pays once that is counted.
A pump, a wheelbarrow run, or a supplier's short-load fee can cost more than the concrete on a small job. They are decisions made before the truck is booked, so they belong on the quote rather than on a surprise invoice.
Say plainly what is included and what triggers an extra charge.
Concrete is one of the few trades where the work is unmistakably complete: it is either down or it is not. Bill it that day, with the yardage, the finish and the terms on the page.
The invoice generator takes the same lines you quoted, so the two documents agree.
The number on this page is only real once it survives the quote, the job and the wait to be paid. These are the three documents that decide whether it does, and the other two are free here as well.
Cost in, margin out, or name the margin you need and take the price it gives you. Check it per line rather than across the whole job.
You are herePut the price in writing with what is included, a deposit and a valid-until date, so the figure you calculated is the figure you are held to.
Open the Quote GeneratorBill the day the work is done, with terms, a due date and a stated late fee. Waiting 60 days for payment can cost more than the job earned.
Open the Invoice GeneratorBorrowing to cover the gap between doing the work and being paid? The loan calculator prices that properly, fees included, so you can compare it against simply asking for a deposit.
Calculating paint in Excel misses doors windows waste and coats. Our calculator prevents short buying and helps you invoice accurately with gallons, cost, labor, total. Part of InvoiceTools suite so you can calculate then create invoice directly.
Accurate gallons for invoice
Wall area 2*(L+W)*H minus doors 21 and windows 15. Example 12x12 room 8ft 384 sq ft walls minus 36 equals 348 paintable 0.99 gal exact 1 gal to buy.
From estimate to invoice in one click
See paint cost gallons times price, labor cost sq ft times rate, total to invoice. Copy invoice line template auto generated.
Unique - Waste, ceiling, labor included
Include ceiling or walls only, 1 2 3 coats, coverage 300-400, labor rate $0.50 to $2, price per gallon $30 to $80.
Built for painting contractors who invoice
Mobile first works on job site, client side only, no data stored. For interior, exterior, residential, commercial.
350 sq ft per gallon per coat typical. Range 300 to 400. Example 400 sq ft living room 1 coat 350 coverage equals 1.14 gallons buy 2 gallons.
200 to 300 sq ft per gallon. New drywall dark to light needs primer. Example 400 sq ft new drywall primer at 250 equals 1.6 gallons buy 2.
250 to 350 sq ft per gallon. Rough stucco lower. Example 1000 sq ft exterior at 300 equals 3.33 gallons buy 4 gallons. Add 10 percent waste.
4 shortcuts from full calculator above. Each answers one question in plain words. Enter numbers, see instant answer. No guessing.
Enter wall length and height. We calculate area and gallons for 1 coat at 350 sq ft per gallon.
Wall Length
Wall Height
Formula: Area = Length × Height, Gallons = Area ÷ 350
Area: 96 sq ft | Paint: 0.27 gal
Example: 12 ft × 8 ft = 96 sq ft = 0.27 gallons (buy 1 gallon).
Enter room length, width, height. We calculate total wall area for 4 walls and gallons for 1 and 2 coats.
Length
Width
Height
Formula: Wall area = 2×(Length+Width)×Height
Walls: 384 sq ft | 1 coat: 1.10 gal | 2 coats: 2.19 gal
Example: 12×12 room 8 ft = 384 sq ft walls = 1.10 gal for 1 coat, 2.19 gal for 2 coats.
If you know total sq ft to paint, enter coverage per gallon (350 standard) and coats. We tell exact gallons and rounded up to buy.
Total Area
Coverage
Coats
Formula: Gallons = Area ÷ Coverage × Coats, Buy = Round up
Exact: 1.14 gal | To buy: 2 gal
Example: 400 sq ft ÷ 350 × 1 coat = 1.14 gal, buy 2 gallons.
Enter gallons you will buy, price per gallon, and labor. We calculate paint cost and total to invoice client.
Gallons to Buy
Price per Gallon
Labor
Formula: Paint Cost = Gallons × Price, Total = Paint Cost + Labor
Paint: $100 | Total to invoice: $400
Example: 2 gal × $50 = $100 paint + $300 labor = $400 total to invoice.
Measure room length width feet height 8 ft standard 9 ft tall. Example 12x12 room 8 ft height wall area 384 sq ft. For single wall use wall only mode.
Count doors windows in room. Each door 21 sq ft each window 15 sq ft subtracted from wall area. Example 1 door 1 window subtract 36 sq ft paintable 348 sq ft more accurate gallons.
Choose 1 2 3 coats 2 standard. Coverage per gallon 350 interior latex 250 primer 300 exterior. Gallons exact paintable area divided by coverage times coats rounded up to buy.
Enter price per gallon $50 typical and labor rate per sq ft $0.75 or flat $300. Paint cost gallons to buy times price labor cost area times rate or flat total to invoice paint plus labor add markup profit 15 to 30 percent.
Copy results or invoice line item template. Example Painting 12x12 room walls 348 sq ft 1 coat 1 gallon at $50 plus labor total $311. Paste into InvoiceTools invoice generator to create professional invoice with client name date terms late fee.
If you invoice painting jobs, you also need these for business. Same browser side no sign up, part of InvoiceTools invoicing toolkit. All indexed as one toolkit for Google.
Invoice Generator
Create painting invoices with gallons, labor, tax, total. Professional PDF for clients.
Use freeConcrete Calculator
Cubic yards, bags, cost for slabs, footings, columns. For contractors who invoice concrete.
Calculate concreteProfit Margin Calculator
$100 cost $150 price equals $50 profit 33% margin 50% markup. Price your painting job for profit.
Calculate marginSurface area equals wall length plus ceiling times height minus windows plus doors. Wall area 2 times length plus width times height. A 12 by 12 room with 8 foot walls leaves 348 square feet once a door and two windows come off. Gallons exact equals paintable area divided by coverage per gallon times number of coats. Coverage typical 350 sq ft per gallon interior latex 200 to 300 primer 250 to 350 exterior. Gallons to buy equals ceil of gallons exact. Paint cost equals gallons to buy times price per gallon. Labor cost equals paintable area times labor rate per sq ft or crew rate 150 to 200 sq ft per hour times hourly rate. Subtotal equals paint cost plus labor plus prep primer trim materials overhead. Total to invoice equals subtotal times 1 plus profit margin 15 to 30 percent plus contingency 5 to 10 percent. No storage no API calculations in browser. Disclaimer estimates for informational purposes only use for invoicing estimates verify with local rates.
Common questions about paint needed, coverage, cost to invoice painting jobs.
Walls and ceiling on a 12 by 12 room with 9 foot ceilings come to about 540 square feet before openings, so two coats at 350 square feet a gallon is roughly 3 gallons. Take off a door and two windows and you are closer to 2.7, which still means buying 3.
Interior work commonly runs $2 to $4 a square foot and exterior $1.50 to $3.50, with hourly rates of $25 to $45 a painter. Where you sit in that range depends on prep more than paint: filling, sanding and masking are the hours that decide whether the job pays.
At typical interior rates, somewhere between $2,000 and $4,000, and the spread is prep and ceiling height rather than paint quality. Price the area here, then add the prep hours honestly, because that is where painting jobs lose money.
Measure the surfaces, take off the openings, decide coats and primer, then price paint and labour separately. The part most estimates miss is condition: bare drywall, rough render and chalky exteriors all drink far more paint than a wall that was painted three years ago.
Two levers, and neither is buying cheaper paint. Cut the time lost to prep you did not quote for by writing surface condition into the quote, and stop absorbing extra coats that were never agreed. A wall that needs three coats should be quoted as three.
One gallon covers roughly 350 square feet in one coat on a previously painted, smooth wall. Two coats halve that to about 175 square feet a gallon, which is the figure to plan with, because one coat rarely looks finished over a colour change.
Walls and ceiling come to about 526 square feet after a door and two windows come off, so two coats need roughly 3 gallons. Walls only is closer to 2.
Measure the perimeter, multiply by the wall height and add the gables, then take off doors and windows. A 120 foot perimeter at 10 feet with 80 square feet of gable is about 1,120 square feet, which is 6 to 7 gallons at two coats.
Yes on bare drywall, new timber, patched repairs and any large colour change, especially light over dark. Primer covers slightly further than topcoat, so treat it as its own coat rather than adding one to the count.
Light texture adds roughly 10 percent, heavy texture or render 25, and bare drywall or timber up to 35. It is the single most common reason a job runs short mid-wall.
By the run, not the room. Multiply the linear feet by the board width in feet, then by the number of faces you are painting. Sixty feet of 5 inch skirting painted on two faces is about 50 square feet, which is well inside a single gallon.
Two on most walls. One is enough only when you are refreshing the same colour on a sound surface, and three is realistic for strong colours, or light over dark, whatever the tin claims.
Work from the area rather than a room size, because a 12 by 12 room with 12 foot ceilings is a third more wall than one with 9 foot ceilings. Price the surface here, add your prep hours, and check the result against what you would want for the day.
Yes, at about 20 square feet a door and 15 a window. On a small room that is over 10 percent of the wall area, which is a gallon on a large job.
Length times width, and nothing else. Ceilings often need an extra coat because they are viewed in raking light, so plan two even when the walls need one.
Trade emulsion is typically $25 to $45 a gallon, and premium or specialist finishes considerably more. On most jobs paint is a fifth or less of the total, so buying cheap paint to save money usually costs more in extra coats.
Yes. No signup, nothing uploaded, and every figure is worked out in your browser and gone when you close the tab.
The surfaces by name, the number of coats, whether primer is included, and what preparation is covered. Most disputes on painting jobs are about prep nobody wrote down, not about paint.
Square foot pricing is easier for a client to compare and easier for you to check afterwards. Day rates hide the prep, which is exactly where painting jobs lose money.
State the number of coats on the quote and price additional coats as a separate line. A wall that needs three coats because of a colour change is a bigger job, and it should be a bigger number.
It usually helps. It shows the client what the materials cost, keeps your labour rate from looking inflated, and makes it obvious why a premium finish costs more.
Part of InvoiceTools.com - Free Invoice Generator, Paint Calculator, Concrete Calculator, Late Fee Calculator, Profit Margin Calculator, Loan Calculator, Salary Calculator, Sales Tax Calculator. Built for contractors, freelancers, small business, agencies who invoice clients. No sign up, client side only, indexed as invoicing toolkit.