Furniture Fit Calculator
Check whether furniture will fit a room or squeeze through a doorway before you buy it.
What this tool does
A furniture fit calculator checks whether furniture dimensions fit into a room or through a doorway before you buy. Enter the furniture size and the opening, and it compares them and calculates the diagonal - the longest straight line across the item, which is the dimension that has to clear a door or a corner. A sofa that is narrower than the door still will not get in if it is deeper than the door is wide when turned on its side.
Checks whether furniture dimensions fit into a room or through a doorway before you buy.
Calculates the diagonal, which is the critical dimension for getting furniture around corners.
Works with any units: cm, inches, mm or feet.
Tests the side-on and end-on orientations, which often give different answers.
How to use it
- Choose a unit: centimetres, millimetres, inches or feet.
- Enter the furniture height, width and depth.
- Enter the door opening height and width.
- Enter the room length and width if you are checking the room too.
- Read whether it fits straight through, on its side, and in the room.
Why use this calculator
Checking whether furniture dimensions fit into a room or through a doorway before you buy is the cheapest thing you can do when furnishing a home. Delivery charges for a failed delivery are real, sofas get returned and re-charged, and the worst case is a piece that goes up the stairs but will not turn into the bedroom. The diagonal is the number that decides it, and it is the one almost nobody measures.
Why we built it
We built the furniture fit calculator to test both orientations at the door, because that is what actually happens: a delivery crew turns a sofa on its side to clear a narrow opening, and what matters then is the diagonal of the depth-and-width plane. The square footage calculator gives the room area, and the moving cost calculator handles the logistics once the piece is bought.
For the wider fit-out, the flooring cost calculator and the paint calculator prepare the room, and the room heating calculator makes sure the heater still fits after the furniture is in.
Who this tool is for
- Anyone buying a sofa, bed or wardrobe online
- People moving into a flat with narrow doors or tight stairs
- Renters checking a piece before ordering delivery
- Interior designers confirming clearances
When to use it
- Before ordering, especially for online purchases.
- When moving into a new place with older, narrower doors.
- Planning a stair turn or a landing corner.
- Checking clearances for drawers, wardrobes and bed lifts.
How it is calculated
Straight fit: furniture width ≤ door width and furniture depth ≤ door height. Side-on fit: the diagonal of the width and depth, sqrt(width² + depth²), must be ≤ the door height, and the third dimension must be ≤ the door width. Room fit: the diagonal of the floor plan, sqrt(length² + width²), must exceed the furniture diagonal if the piece is to sit at an angle.
Worked example: a sofa 220 × 95 × 85 cm facing a door 80 cm wide by 200 cm high. Straight through fails, because 95 cm is wider than the 80 cm opening. Turned on its side, the diagonal of 220 and 95 is sqrt(48,400 + 9,025) = 239.6 cm, which is longer than the 200 cm door height, so it does not fit either - and the answer is a modular sofa or a window delivery.
A door that is 80 cm wide and 200 cm high gives a clear diagonal of sqrt(64,000 + 40,000) = 253 cm - that is the largest straight line that can pass through, and it is the ceiling on what will ever get in.
Common opening sizes
| Opening | Width × height | Clear diagonal |
|---|---|---|
| UK internal door | 76 × 198 cm | 212 cm |
| US interior door | 76 × 203 cm | 217 cm |
| Wide internal door | 84 × 204 cm | 221 cm |
| Patio / French door | 150 × 210 cm | 258 cm |
| Standard lift | 110 × 210 cm | 237 cm |
A worked example
These are the values the calculator opens with, so you can see exactly what it does with them. Change any value on the page and the result updates; the figures below come from the same calculation.
| Input | Value |
|---|---|
| Units | Centimetres |
| Furniture | 200 W × 90 D × 85 H cm |
| Door opening | 80 W × 200 H cm |
| Room | 400 × 350 cm |
With those inputs, the calculator returns:
- Furniture diagonal: 219.3 cm
- Straight through the door: no - 90 cm is wider than 80 cm
- Side-on through the door: yes - 219.3 cm fits the 200 cm height with the 85 cm edge leading
- Room diagonal: 531.5 cm - plenty of room to angle the piece
- Clearance in the room: 200 cm along the 400 cm wall
Tight spots and how to handle them
Most failures happen at three places: the front door, the turn at the top of the stairs, and the bedroom door after the landing. Measure all three. A piece that clears the front door and the stairs can still fail at a low ceiling above the last step.
| Location | Measure |
|---|---|
| Front door | Clear width and height, minus the frame and any stops |
| Hallway | Width, and any radiators or shelves that narrow it |
| Stair turn | Landing depth and the ceiling height over the turn |
| Room door | Clear opening, and which way it swings |
| Room itself | Length, width and where the other doors and windows fall |
What you enter, and what you get back
| Item | Details |
|---|---|
| Furniture dimensions | Height, width and depth in any unit. |
| Door opening | Clear width and height. |
| Room | Optional length and width. |
| Result | Diagonal, straight fit, side-on fit and room fit. |
Issues you may run into
| What you see | Why it happens | What to do |
|---|---|---|
| Fits on paper, fails on the day | Door measured to the frame, not the clear opening. | Subtract the frame, stops and any architrave. |
| Stair turn fails | Landing depth not checked. | Measure the landing and the ceiling height over the turn. |
| Wardrobe will not go in | Assembled width is wider than the flat-packed box. | Check the assembled dimensions, not the packaging. |
| Drawers will not open | Clearance not allowed in front. | Add 45 to 60 cm in front for full drawer travel. |
Assumptions and limitations
- Assumes rectangular furniture and openings - curved or angled pieces need a different check.
- Does not model handles, feet, skirting or doorstops that reduce the clear opening.
- Stair and corner turns need a plan view; this calculator checks straight runs only.
- When in doubt, measure twice and ask the retailer for the assembled dimensions.
Frequently asked questions
Will my sofa fit through the door?
Compare the sofa depth with the door width, and the diagonal of the width and depth with the door height. A sofa 95 cm deep will not pass an 80 cm door straight on, but it may go through on its side if sqrt(width² + depth²) is under the door height. If both fail, ask for a modular version or a window delivery.
How do I check if furniture fits in a room?
Measure the room length and width, then compare the furniture footprint against it, allowing for doors to open and drawers to travel - roughly 45 to 60 cm in front of any drawer or wardrobe door. The room diagonal tells you whether the piece can sit at an angle, which often solves a tight fit.
What is the diagonal measurement?
The longest straight line across an object, found as sqrt(length² + width²) for the plane concerned. For fitting furniture through a door, the relevant diagonal is across the two smallest dimensions, because that is the line that must pass through the opening when the piece is turned.
How do I measure a doorway for furniture?
Measure the clear width between the frame or stops, and the clear height to the threshold or the bottom of the frame - not the rough opening. Subtract nothing for handles on the furniture; add nothing for optimism. If there is a step or a raised threshold, measure from the top of it.
How much clearance do I need?
Allow 45 to 60 cm in front of any drawer, wardrobe or cabinet door for full travel, 90 to 120 cm for a walkway past the furniture, and 45 to 75 cm between a bed and a wall if you want to walk past. Dining chairs need about 90 cm behind them when someone is seated.
Will a bed fit up the stairs?
Measure the stair width, the landing depth and the ceiling height over the turn, then compare them with the diagonal of the headboard or base. Divan bases often split in two, which is why they go up stairs that a solid frame cannot. Always check the assembled dimensions, not the packaging size.