Free rug size calculator
Find the right area-rug size in seconds. Enter your room's length and width and the border of bare floor you want around the rug, and the calculator returns the recommended dimensions, the nearest standard size you can actually buy, the floor coverage, and the furniture-placement rule — updated live, as you type.
On this page15 sections
A starting point based on the border rule. Confirm against your furniture and taste.
Results are estimates. Consult a professional.
How the rug size calculator works
A rug should frame a room, not carpet it wall to wall. The calculator starts from that idea. It takes your room's length and width, subtracts a strip of bare floor — the border — from each side, and treats what's left as the largest rug the room can hold gracefully. Then it snaps that figure down to a real standard size you can buy, and tells you which placement rule that size supports.
Why snap down to a standard size
Rugs are sold in fixed sizes, not made to order, so the recommended rectangle is only useful once it maps to something on the shelf. The calculator picks the largest standard size whose length and width both fit inside that rectangle. Snapping down — never up — means the border you asked for is preserved or slightly larger, never eaten into.
What decides the right rug size
Three inputs set the answer. Get them right and the size is right; guess at one and you risk a rug that swamps the room or floats lost in the middle of it.
Room dimensions — the starting rectangle
Measure the room's length and width in feet, wall to wall, in the area the rug will sit. For an open-plan space, measure the zone you're furnishing — the seating area, the dining area — not the whole floor. Orientation doesn't matter to the math: the calculator compares the room's long and short sides to the rug's, so a 12 by 15 room and a 15 by 12 room get the same answer.
Border — the bare-floor frame
The border is the gap of exposed floor between the rug edge and each wall. About 18 inches is the classic target, and the calculator defaults to it. A workable range runs from 8 inches in a small room up to 24 inches in a large one. A wider border shrinks the rug; a narrow border lets a bigger size in.
Standard size ladder — what you can buy
Retailers stock a fixed ladder of sizes: 2×3, 3×5, 4×6, 5×7, 6×9, 8×10, 9×12, and 10×14 feet. The calculator chooses the largest rung that fits your recommended rectangle. That's the size to search for, and it's why two rooms a foot apart can land on the same rug.
What size rug for a 12 × 15 ft living room
Mara is buying a rug for a 12 ft × 15 ft living room and wants the classic 18-inch frame of bare floor around it. She needs to know the recommended dimensions, the standard size to search for, and whether her sofa legs will sit on it.
Step 1 — Subtract the border from each side
The long wall is 15 ft = 180 in; minus 18 in on both sides gives 180 − 36 = 144 in, which is 12 ft. The short wall is 12 ft = 144 in; minus 36 in gives 108 in, which is 9 ft.
Step 2 — Snap to the nearest standard size
The recommended rectangle is 9 ft × 12 ft. The largest standard size that fits inside it is the 9 × 12 ft rug — the most popular living-room size there is.
Step 3 — Read the placement rule
A 9×12 covers 108 of the room's 180 square feet — about 60% coverage. Above 55%, the rug runs under every furniture leg, so Mara gets the grounded, all-legs-on look without the rug crowding the walls.
Standard rug sizes chart
Area rugs come in a fixed set of sizes. This chart lists the common ones, the room they suit, and the rule of thumb each is known for. Use it to sanity-check the calculator's pick.
| Standard size | Area (ft²) | Typically suits |
|---|---|---|
| 2 × 3 ft | 6 | Entryways, doormats, kitchen sink |
| 3 × 5 ft | 15 | Small kitchens, foyers, accent spots |
| 4 × 6 ft | 24 | Reading nooks, under a coffee table |
| 5 × 7 ft | 35 | Small living rooms, apartments |
| 6 × 9 ft | 54 | Medium living rooms, under a queen bed foot |
| 8 × 10 ft | 80 | Standard living rooms, dining for 6 |
| 9 × 12 ft | 108 | Large living rooms, king bed, dining for 8 |
| 10 × 14 ft | 140 | Great rooms, open-plan seating areas |
The size ladder retailers stock, from The Spruce, Ruggable, and Pottery Barn rug guides. Runners (2–3 ft wide) and round rugs (4, 6, 8 ft) sit outside this chart.
What size rug do I need for my room?
If you want a fast answer before you measure, this table gives the recommended size for common room dimensions at the standard 18-inch border. The coverage and placement come straight from the calculator.
| Room size | Recommended rug | Standard size | Placement |
|---|---|---|---|
| 8 × 10 ft | 5 × 7 ft | 5 × 7 ft | Front legs on (44%) |
| 10 × 10 ft | 7 × 7 ft | 5 × 7 ft | Front legs on (35%) |
| 10 × 12 ft | 7 × 9 ft | 6 × 9 ft | Front legs on (45%) |
| 11 × 13 ft | 8 × 10 ft | 8 × 10 ft | All legs on (56%) |
| 12 × 15 ft | 9 × 12 ft | 9 × 12 ft | All legs on (60%) |
| 12 × 18 ft | 9 × 15 ft | 9 × 12 ft | Front legs on (50%) |
| 14 × 20 ft | 11 × 17 ft | 10 × 14 ft | Front legs on (50%) |
All rows use an 18-inch border. "Recommended rug" is the bare rectangle; "Standard size" is the largest stocked rug that fits inside it.
The 18-inch rule (and when to break it)
The 18-inch rule is the single guideline most designers reach for: leave about 18 inches of bare floor between the rug and the walls. That strip gives the room proportion and stops the rug from reading like fitted carpet. It's a target, not a law.
The 8-to-24-inch range
Eighteen inches is the middle of a usable range. In a small room or a tight hallway, 8 to 12 inches keeps the rug from looking stranded. In a large or open-plan space, you can stretch the border to 24 inches so the rug still has room to breathe. The calculator lets you set the border anywhere in that range and recomputes the size live.
When a consistent border matters more
In an L-shaped or open-plan room the walls don't form a tidy rectangle, so chasing an exact 18 inches on every side is pointless. Aim instead for an even border on the two sides that read most — usually the entry and the main seating wall — and let the rug float over the rest.
Rug placement rules: all legs, front legs, or floating
Size and placement are the same decision. How much of your furniture sits on the rug depends on how much of the room the rug covers — and that's exactly what the calculator reports alongside the size.
| Placement | Room coverage | What it looks like |
|---|---|---|
| All legs on | 55% and up | Every sofa, chair, and table leg sits on the rug — the most grounded, pulled-together look |
| Front legs on | 30% to 55% | Front legs of seating rest on the rug; back legs on bare floor — the most common living-room setup |
| Floating | Under 30% | The rug sits in the center, often under a coffee table, with no furniture legs on it — works in small or layered spaces |
Coverage is the rug's area divided by the room's area. Thresholds reflect the front-legs-on and all-legs-on rules from Pottery Barn and Ruggable.
The one look to avoid is the "floating island" — a rug too small to catch any furniture legs in a room big enough to need them. If the calculator returns a floating result in a large room, size up or pull the seating closer together. You can sanity-check your room's footprint with the square footage calculator.
8×10 vs 9×12: which rug to choose
These two sizes cover most living rooms, and the choice between them trips people up. The difference is 28 square feet — a 9×12 is roughly a third bigger — and that gap decides whether your back furniture legs make it onto the rug.
| Size | Best room | Furniture fit |
|---|---|---|
| 8 × 10 ft | Rooms about 11 × 13 ft | Front legs of the sofa and chairs; coffee table fully on |
| 9 × 12 ft | Rooms about 12 × 18 ft or larger | All legs of a standard sofa, loveseat, and chairs |
Room-fit ranges follow the Ruggable rug-size guide. Measure before you commit — a foot of room either way moves the answer.
Rule of thumb: if your room is 12 feet or wider and you want every leg on the rug, go 9×12. If it's nearer 11 feet wide, or you're happy with the front-legs-on look, the 8×10 leaves a cleaner border. When the calculator lists both as fitting, it picks the larger — but the smaller is a valid choice if you prefer more bare floor.
Rug size definitions
How accurate is this rug size calculator?
The geometry is exact. Subtracting the border from each side and snapping to the largest standard size that fits is precise arithmetic, so if your room measurements are right, the recommended size is right. The same goes for the coverage figure and the placement rule it implies.
What the calculator can't see is your furniture and your taste. The placement thresholds are conventions, not rules — designers break them all the time, sizing up for a bolder look or down for more bare floor. Treat the size as a strong starting point: confirm it against your actual sofa footprint, and if you're between two sizes, the larger one is the safer buy in most living rooms. For dining rooms, remember the rug needs to clear the pulled-out chairs, not just the table.
Border and placement guidance drawn from the Pottery Barn rug buying guide and The Spruce rug size guide; standard sizes and room-fit ranges from Ruggable.Frequently asked questions about the free rug size calculator
About this rug size calculator
This rug size calculator runs entirely in your browser — nothing you type is sent anywhere, and the result updates instantly as you change the room size or border. It uses the designer's border rule (about 18 inches of bare floor on each side), then snaps the recommended dimensions down to the nearest real standard rug size so you know exactly what to search for.
It's part of our home & garden calculators — alongside square-footage, flooring, and paint tools — and the full library of free calculators covering finance, health, and more.