How much space do you need for a piano?

A full-size upright piano needs about 54 in (138 cm) of floor from the wall to the back of the bench. A grand needs its length plus 24 in (61 cm). Both are about 5 ft wide, give or take 3 in. The extra 24 in is the bench pulled out with someone sitting on it, and Yamaha tells buyers to add exactly that. The two room rules that circulate, a 2 x 2 m room and walls ten times the piano's length, answer different questions. The first is wrong on its own numbers, and the second is about sound.

Footprint, length and depth: what a piano spec measures#

A piano's footprint is the rectangle of floor it covers. Makers print it as width and depth, and the two types use the words differently.

On a grand, the "depth" on a Yamaha spec page is what everyone else calls the length. Yamaha's buying guide defines it: grand length runs from the key slip, the strip of wood in front of the keys, to the far end of the lid. The width is across the keyboard end. The long straight side on the left is the spine, and the curved side on the right is where the lid opens.

On an upright, depth is the short distance from the back of the case to the front of the keyboard, and height matters too, because one of the room rules uses it.

Width barely changes: Yamaha notes that almost every piano is about 5 ft wide, because every one carries the same 88-key keyboard. Across the 19 models on this page it runs from 146 to 160 cm (57 to 63 in), so the room pays for depth, and for the player.

That brings in the second term this page uses. The playing footprint is the footprint plus the bench and the person on it, the space a piano takes when someone plays it. Yamaha's guide says to trace the piano's outline on paper and "add an extra 2 feet to the depth" for the bench pulled out. Every figure below adds those 24 in (61 cm).

13 grands: length plus 24 in for the bench#

The table takes length, width and weight from the makers' own spec pages: Yamaha's GB1K, CX Series and CF Series, and Steinway's S, M, O, A, B and D. The last column adds Yamaha's 24 in.

Two things stand out: width moves by only 14 cm (6 in) from the smallest grand to the largest, while length nearly doubles. The figures that circulate check out against the makers: Yamaha's C3X is 149 x 186 cm, and Steinway's own pages give the B at 211 cm (6 ft 11 in) and the M at 170 cm (5 ft 7 in).

The rectangle overstates the floor the tail covers, since the curved side cuts in, but the cut-away corner is too small and awkward for any other furniture, so plan the full rectangle.

Uprights: 54 in from the wall for a Yamaha U1#

An upright goes with its back to a wall, and Yamaha's owner's manual says so for safety, because an upright's weight sits towards the back. The same manual gives the gap as 10 to 15 cm (4 to 6 in), which it says "improves ventilation and allows the sound to resonate".

So an upright's playing depth is the gap, plus the piano, plus 61 cm (24 in). The table uses the 15 cm end of Yamaha's range, which also clears a skirting board. Sizes are from Yamaha's U Series, YUS Series, B Series and JU Series pages.

Yamaha's B Series is now listed as the B10, B20 and B30. The older b1 name does not appear on the current spec page, so it is not in the table.

The spread is small: every upright here needs 130 to 141 cm (51 to 56 in) from the wall. Add a 30 in (76 cm) path behind the bench, the secondary route in the site's walkway and circulation widths, and a U1 claims 214 cm (7 ft) of the room's depth.

Corners need one more figure, and Thomann's guide says an upright should sit at least 50 cm (20 in) from an adjoining wall, so a technician can work on it. A U1 in a corner therefore takes 203 cm (80 in) of wall, not 153 cm.

The lid needs no floor, but it needs the curved side#

A grand's lid is hinged along the spine, and it lifts on the curved side to rest on a prop. Seen from above, the open lid stays over the case, so the lid adds no floor to the footprint.

It does add a standing place, because Yamaha's manual has the adult start "at the front right side of the piano". They fold the front lid onto the main lid, lift both with two hands, then hold them with the right hand and set the prop with the left. The GB1K has two prop positions, and nobody can do that from a gap of a few inches. This page keeps a 30 in (76 cm) path along the curved side, which is the site's own application of the walkway figure.

The curved side is also where the sound goes: Thomann says the open lid should point into the room. Yamaha's guide says grands sound best in the middle of a room, or at 45 degrees in a corner. So the only side that can take a wall without losing anything is the spine. Yamaha gives no wall gap for grands, so this page uses its 10 to 15 cm upright figure for the spine and tail, as the site's recommendation.

2 x 2 m or ten times the length: which rule is right#

The two rules on dealer pages cannot both hold, and the arithmetic shows why.

Millers Music writes that a room of "4 metres squared (2m x 2m)" is "just about large enough" for a grand, if nothing else large is in it. Test it on the shortest grand in the table, the GB1K, which is 151 cm (5 ft) long. With Yamaha's 2 ft for the bench it is 212 cm (83 in), which is 12 cm longer than the room, so the piano fits only with nobody playing it.

The other rule comes from Yamaha's own guide and from Piano Buyer: the room's walls, added together, should total at least ten times the grand's length. Piano Buyer applies it to an upright's height too, and raises it to 15 times for ensemble playing. A 2 x 2 m room has 8 m (26 ft) of wall, while ten times a GB1K is 15.1 m (49 ft 6 in). By that rule the 2 x 2 m room is about half the size.

The rules disagree because they measure different things, and the ten times rule is about sound. Yamaha calls it a rule of thumb "for optimum sonics", and gives a 9 ft grand 90 ft of wall. It is not a fit minimum, while the 2 x 2 m figure claims to be a fit minimum and fails as one.

Fit is the playing footprint plus the paths around it. Here are the three figures side by side. The ten times rooms use Piano Buyer's own 2 : 3 shape, from its example of a 7 ft grand in a 14 x 21 ft room, because it warns against square rooms.

The fit zone is this page's assembly. For a grand it is 15 cm at the spine, the width, and 76 cm on the lid side. Lengthways it is 15 cm at the tail, the length, 61 cm of bench and a 76 cm path. For the U1 it is the 138 cm playing depth plus the path. Thomann gives a fourth figure for any grand: "at least 50 m³", which it turns into 20 m² (215 sq ft) of floor under a 2.5 m ceiling.

A 12 x 14 ft living room, worked through#

Take a living room of 12 x 14 ft (3.66 x 4.27 m), and suppose the choice is between a Yamaha U1 and a grand. Here is how the published figures play out.

The sound rule first. The walls add up to 52 ft (15.85 m), and a tenth of that is 1.58 m (5 ft 2 in). The GB1K at 151 cm passes, and so does the Steinway S at 155 cm, but the C1X at 161 cm does not. The U1 needs only 12.1 m of wall for its 121 cm height, so it passes easily.

Then fit. Set the GB1K with its spine along a 14 ft wall. Across the room it takes 15 cm of gap, 146 cm of piano and 76 cm of lid-side path, which is 237 cm and leaves 129 cm (51 in). Along the wall it takes 303 cm, leaving 124 cm (49 in). The zone is about 7.2 m² of the room's 15.6 m², or 46 per cent.

A standard 84 x 38 in sofa, from sofa dimensions, is 97 cm (38 in) deep, so in either strip it leaves 32 cm (13 in) or less to walk past. The room has become a piano room with a chair in it.

The upright. The U1 takes 153 x 138 cm (60 x 54 in) when played, about 2.1 m², and its path behind the bench can be the room's own route, so the extra floor is shared. That leaves room for the seating plans in living room seating layout dimensions.

So the walkthrough gives a clear answer for this room. A grand of 5 ft 2 in or less is allowed by the sound rule and fits, but it takes almost half the floor. If the room also has to seat four, the upright is the piano that works. The site's small living room layouts show what the rest of a room this size can hold.

Radiators, outside walls and the 35 to 70 per cent band#

No maker or dealer source checked for this page gives a distance from a radiator, but they do give the condition the distance is meant to protect.

Yamaha's owner's manual sets the range: 20 to 30 °C (68 to 86 °F) at 40 to 70 per cent relative humidity in humid seasons, and 10 to 20 °C (50 to 68 °F) at 35 to 65 per cent in dry ones. It says to avoid "excessive dryness or heated areas", which can loosen screws, crack parts and put the piano out of tune. Yamaha's buying guide adds direct sun and air vents, and Thomann says to avoid temperature drops of more than 4 °C and aims for 50 to 60 per cent humidity.

Kawai's placement guidance adds exterior walls, open windows and west-facing walls that heat up in the afternoon sun. Thomann warns that some makers void the warranty on underfloor heating, so read yours before you put a piano over it. A fireplace is a heat source too, and the site's fireplace and media wall dimensions cover what else that wall carries.

So the working rule is a measurement, not a distance: put a hygrometer on the piano through the first heating season. If it reads below the band while the radiator is on, the piano is too close, wherever the tape says it is.

Floor load: an upright presses twice as hard as a grand#

Yamaha's manual says to install a piano "on a strong, flat floor" and to choose the spot by its weight. It gives 250 to 500 kg (550 to 1,100 lb) for grands and 190 to 280 kg (420 to 620 lb) for uprights.

The design figure to compare against is the IRC's uniform live load: 40 psf (1.9 kPa) for living areas and 30 psf in sleeping areas. Spread each piano's weight over its own footprint and the result runs against intuition.

Every upright comes out above 40 psf on its own footprint, and every grand comes out near 24 psf, even the 485 kg concert grand. A grand is heavier, but it spreads its weight over more than twice the floor. The grand figures use the full rectangle, so a grand's true average is somewhat higher, but it still stays well below the uprights.

None of this predicts a failure, because joists and floorboards spread a load sideways, and the same point is made for weight racks in free weight and bench space. Across a whole room the average is a few psf, but an upright on a long, springy span, or on joists that have been notched, is the case to have looked at. Yamaha also suggests caster cups, so the casters do not mark the floor.

What these numbers do not cover#

These figures size the floor, and they are not an acoustic design. The ten times rule is a starting point, and Piano Buyer says it ignores openings into other rooms and irregular shapes. Room proportions also shape the bass, which home theatre room dimensions works through for speakers.

They do not cover getting the piano in, which doors, stairs and turns decide, and the four measurements are in furniture delivery path. A piano is a job for a specialist mover, as Yamaha's manual says.

They do not cover the floor's structure. The load table compares averages with a code design figure, and it is not an engineer's check of your joists.

They do not cover digital pianos, other makes, or other bench sizes, and a different model needs its own spec sheet, plus the same 24 in.

Six checks with a tape measure#

Mark the zone on the floor with masking tape before the piano arrives. Millers Music and Yamaha both suggest a paper outline, and the planning section covers taping a layout at full size. For the sizes of everything else in the room, start from furniture dimensions.