All calculators & tools
Every estimation tool on this site, in one organized directory — all free, all running in your browser, all storing nothing on our servers. The flagship primer calculator carries the whole toolchain on one page; the sections below organize its features into the three jobs they do — estimating, purchasing, and getting the result where it needs to go.
The primer calculator
One page, one engine, the whole job. Enter a room or a square footage and the calculator applies surface-specific coverage rates, deducts doors and windows, recommends coats for your objective, and converts the volume into the exact cans, pails and quarts to carry to the counter — with a cost total once you enter a price. No account, no upload, no waiting: the result updates live as you type.
It is deliberately opinionated about rounding. Paint is sold in whole cans, so the purchase plan rounds up and shows the spare volume explicitly; assumptions — coverage rates, opening sizes, flat pricing — are printed next to the numbers they affect. Every calculation is also encoded into the page URL, so the link you text to a partner or hand to the paint counter reopens with your exact inputs loaded.
You get, per run
- →Gallons & quarts of primer needed
- →Net area with openings deducted
- →Objective-based coat recommendation
- →Can-and-pail purchase plan
- →Spare volume for touch-ups
- →Total material cost
- →US & metric units in sync
- →Save / share / print
🧮Estimating tools
Turn what you know — a room's footprint, a measured wall, a surface type — into a defensible primer volume.
Every wrong primer purchase starts as an estimating error, so this is the layer the site invests in most. The flagship calculator accepts two kinds of input: a room's dimensions, which it converts into gross wall area before subtracting standard doors (21 sq ft) and windows (15 sq ft), or a directly measured area for ceilings, fences, and irregular walls. From there it applies the coverage rate that matches your actual surface — because new drywall at 350 sq ft/gal, bare wood at 250, masonry at 200 and previously painted walls at 400 can differ by a factor of two on the same square footage.
The final estimating input is the one most calculators ignore: why you are priming. Standard prep, a dark-to-light color change, stain or odor sealing, and high-porosity bare surfaces each carry a recommended coat count drawn from trade practice. Choosing the objective applies it automatically — and you can override it when the wall in front of you says otherwise.
Room-dimensions mode
Enter length, width and wall height. The calculator computes gross wall area, deducts doors and windows at standard sizes, and shows gross, deducted and net figures as separate line items you can audit.
Direct-area mode
Already know the square footage — or priming a ceiling, a fence or an exterior wall? Type the area straight in and skip the room math entirely.
Surface-specific coverage rates
Four planning profiles — new drywall (350 sq ft/gal), bare wood (250), masonry/concrete (200), previously painted (400) — replace the one-rate-fits-all guess that ruins most estimates.
Objective-based coats
Standard prep takes one coat; dark-to-light changes, stain and odor sealing, and porous bare surfaces take two. The recommendation applies itself and stays overridable.
🛒Purchase & budgeting tools
Convert a decimal you cannot buy into cans, pails, spare product and a total you can plan around.
A result like 3.14 gallons is where other estimators stop — and where the paint counter starts. This layer rounds the computed volume up into real retail packaging, using whichever packaging mode fits the job: automatic (pails first, then gallons, then quarts), 1-gallon cans, 5-gallon pails, or quarts for patch-and-trim work. The spare volume left over is displayed explicitly, because that leftover quart is your touch-up supply, not a rounding error.
Enter a local price per gallon and the cost panel totals the job twice: the true material cost of the raw volume, and the till cost of the rounded-up can mix. The gap between those numbers is small but real — and seeing it before checkout beats discovering it on the receipt.
Package planner
Four packaging modes — Auto, 1-gal, 5-gal, 1-qt — turn volume into the exact cans and pails to carry to the counter, matched to how large the job is.
Spare-volume disclosure
The plan shows the leftover product explicitly — the reserve for touch-ups and second coats, printed next to the purchase list instead of hidden in a decimal.
Cost estimator
Enter your local price per gallon to see the raw material cost and the rounded-up till total side by side, in US or metric purchasing terms.
⚙️Workflow & output tools
The unglamorous features that decide whether an estimate survives contact with a real project.
Estimates get used in kitchens, hallways and store aisles — not ideal lighting with a spreadsheet open. So the calculator keeps both unit systems live at once: switching Imperial to Metric converts every input and output in sync, including the door and window assumptions (0.9 × 2.1 m and 1.2 × 1.2 m), so a metric estimate is never a rounded conversion of an imperial one.
Results can be saved to your browser's local storage for project files, reset in one click, printed for the paint counter, or encoded into the page URL. A share link carries your exact inputs — area, surface, coats, waste — so the same numbers reopen on any device, and nobody re-types a wall's dimensions from memory.
US & metric in sync
One switch converts every input and output between sq ft/gal and m²/L — including opening deductions — with values rounded for readability, never re-estimated.
Save, reset & print
Saved results live in your browser's local storage only — nothing uploads, nothing syncs, and clearing them takes one click. Print a clean copy for the job folder.
Shareable result links
Every calculation encodes into the page URL. Text it to a partner or hand it to the counter staff — the link reopens with your exact inputs loaded.
Room mode vs. area mode, side by side
Both modes feed the same engine. Pick by what you actually know: a room's footprint, or a measured surface.
| Aspect | 📐 Room-dimensions mode | 📏 Direct-area mode |
|---|---|---|
| What you type | Length, width, wall height, plus counts of doors and windows | A single square-footage or square-meter figure |
| Deductions | Automatic — standard door (21 sq ft) and window (15 sq ft) per opening | None — measure around openings or deduct them yourself |
| Best for | Interiors: bedrooms, living rooms, whole floors, repainting projects | Ceilings, fences, exterior walls, closets and irregular shapes |
| Ceiling checkbox | Included — adds length × width with one toggle | Add the ceiling area to your figure yourself |
| Metric mirror | 0.9 × 2.1 m doors, 1.2 × 1.2 m windows, results in m² and liters | Identical math, metric units throughout |
Same area, four very different jobs
Why surface selection matters more than any other input: one coat over 1,000 sq ft with 10% waste, priced out per surface profile. The spread from cheapest to thirstiest is nearly double — enough to turn a one-can job into a pail job.
| Surface | Rate | 1,000 sq ft, 1 coat | Example purchase mix |
|---|---|---|---|
| New drywall | 350 sq ft/gal | ≈ 3.2 gal | 3 × 1-gal + 1 × 1-qt |
| Previously painted | 400 sq ft/gal | ≈ 2.8 gal | 2 × 1-gal + 3 × 1-qt |
| Bare wood | 250 sq ft/gal | ≈ 4.4 gal | 4 × 1-gal + 2 × 1-qt |
| Masonry & concrete | 200 sq ft/gal | ≈ 5.5 gal | 1 × 5-gal pail + 2 × 1-qt |
Where the toolchain earns its keep
Six situations where guessing wrong costs real money — and where the surface-specific math pays for itself the first time you use it.
🏗️New drywall in a remodel
Fresh drywall soaks primer fast. Room mode converts your wall dimensions into net area, applies the 350 sq ft/gal PVA rate, and sizes the purchase accordingly.
🎨Dark wall going light
A dramatic color change usually means two coats. Pick the objective and the calculator doubles the volume — before you discover it halfway up a ladder.
🧯Sealing stains and odors
Water stains, smoke, and kitchen grease need stain-blocking primer, often in two coats. The estimator sizes the job so the seal actually holds.
🪵Bare wood and masonry
Porous surfaces at 200–250 sq ft/gal can need half again more product than drywall. Enter the area, choose the surface, and buy for reality.
🏢Rental turnovers
Between tenants, walls are usually previously painted — the 400 sq ft/gal profile — with the odd patched spot to seal. Area mode plus a bump in waste covers the patchwork quickly.
🌇Ceilings and whole floors
Add the ceiling with one checkbox in room mode, or run a multi-room job as several estimates saved to the same browser — each with its own can mix.
How a run works, start to checkout
The toolchain is designed as one pass, not a quiz. Five steps, about two minutes.
- 1
Measure the surface
Room dimensions with automatic door and window deductions — or a known square footage typed straight in. Either way, the gross, deducted and net areas stay visible so you can audit every step.
- 2
Select the surface type
New drywall, bare wood, masonry or previously painted — each maps to its industry-standard coverage rate. This single choice moves the volume more than any other input, which is why it sits in step two.
- 3
Pick the project objective
Standard prep, color change, stain sealing or porous bare surface — the recommended coat count follows automatically. Override it if the wall tells you something the dropdown can't know.
- 4
Set coats and waste
10% waste suits roller and brush work; raise it to 15–20% for spraying. Every downstream number — gallons, cans, cost — adjusts the moment you change it.
- 5
Buy and budget
Volume converts into whole cans and pails, the spare is shown explicitly, and a price per gallon totals the job. Copy the URL to hand the exact inputs to whoever is holding the wallet.
On the drawing board
Each of these becomes a standalone page once its math is verified against real product data sheets. Current candidates, in the order painters keep asking for them:
🖌️Paint calculatorComing soon
Finish-coat volumes with sheen-aware coverage rates, for when the priming is done. Flat, eggshell and gloss hide differently — the tool will respect that.
🧻Wallpaper calculatorComing soon
Rolls needed from wall dimensions, pattern repeat and door/window deductions — the same room-mode geometry, aimed at paste instead of primer.
💸Paint cost comparisonComing soon
Compare two products' real cost per covered square foot — premium cans against budget ones, using each product's own stated coverage.
💨Spray coverage estimatorComing soon
Transfer-efficiency-aware volumes for sprayer setups, where waste factors shift sharply with tip size, pressure and operator technique.
Tool questions, answered
Are all of these tools really one calculator?+
Yes — every feature above lives inside the flagship calculator on the homepage, so your inputs feed everything at once. As standalone pages launch, they'll appear in the registry list below and in the header's Calculators dropdown.
Do I need to fill in every input?+
No. A square footage alone produces a working estimate. Each input you add — room dimensions, surface type, objective, price — sharpens the result and the purchase plan it produces.
Which packaging mode should I pick?+
Auto suits most jobs: it fills a 5-gallon pail first on large volumes, then 1-gallon cans, then rounds the remainder to quarts. Force 1-gallon for multi-room work you want to carry can by can, 5-gallon for whole-home jobs where the per-gallon price drops, and quarts for doors, trim and patch tests.
Does the estimate include ceilings and trim?+
Ceilings: yes in room mode — one checkbox adds length × width. Trim, doors and baseboards are not part of the wall figure; measure them separately and add their area if you'll prime them in the same pass.
Can I trust the recommended coat count?+
It encodes standard trade practice — one coat for sound surfaces, two for dark-to-light changes, stain and odor sealing, and porous bare surfaces. It is a recommendation, not a rule: override it when your surface, or your product's data sheet, says otherwise.
What tools are coming next?+
A finish-coat paint calculator and a wallpaper calculator lead the list, followed by cost-comparison and spray-specific estimators. Nothing ships until its math is honest.
Looking for the reading behind the numbers? The painting guides cover coverage, prep and buying in depth — or go straight to the calculator.
One room is all it takes to start
Grab the tape measure, enter a room or a square footage, and watch the toolchain turn it into gallons, cans and cost.
🖌️ Run the calculator