Quilt Size & Bed Overhang Calculator
Standard quilt sizes assume a 13-inch mattress. On the deep ones now sold, 14 of 30 combinations are short — and every one is short in length.
The standard sizes assume a mattress nobody owns any more
Work backwards from the sizes everyone quotes and you can read off the bed they were designed for. A queen quilt at 90 inches on a 60-inch mattress gives a 15-inch drop, and if you want it to hang two inches below the bottom edge, that clears a mattress 13 inches deep. Every standard size makes the same shallow assumption.
| Bed | Standard quilt | Clears | 9″ | 11″ | 14″ | 16″ | 18″ |
|---|---|---|---|---|---|---|---|
| Twin | 70×90″ | 14″ | ok | ok | ok | −2″ | −4″ |
| Twin XL | 70×95″ | 14″ | ok | ok | ok | −2″ | −4″ |
| Full | 84×92″ | 13″ | ok | ok | −1″ | −3″ | −5″ |
| Queen | 90×100″ | 13″ | ok | ok | −1″ | −3″ | −5″ |
| King | 108×100″ | 14″ | ok | ok | ok | −2″ | −4″ |
| California King | 104×104″ | 14″ | ok | ok | ok | −2″ | −4″ |
14 of 30 combinations leave the quilt short of the rail. The worst — a full-size quilt on an 18-inch pillow-top — misses by five inches a side, which is not a styling preference, it is a quilt that does not reach.
The length is worse, and it is the one people miss
A quilt has to do three separate things down the bed: cover the mattress, drop at the foot, and fold back over the pillows. Only the first of those is the mattress length.
length = mattress + (depth + hang) + pillow tuck
A twin quilt on an ordinary 11-inch mattress needs 98 inches against a standard 90. Checking every bed against every depth, all thirty come up short in length — including a queen on a modest mattress. The width can be argued about; the length simply is not enough.
And a correctly sized quilt is not centred
Because there is a tuck at the head and only a drop at the foot, the two ends are different lengths — so the quilt does not sit centred on the mattress. Centre it and you lose the tuck at the top while trailing on the floor at the bottom. The tool tells you how far off centre it should sit, and which way. It is worth marking the quilt's centre line with a pin before you put it on the bed, because it will look wrong until you check it.
Notes
- Measure the mattress depth. It is the one number that has changed, it varies from about 9 to 18 inches, and it is the input every standard size gets wrong. A tape measure at the corner takes ten seconds.
- Measure it made up. A mattress protector and a fitted sheet add real depth, and a topper adds several inches. Measure what the quilt will actually go over.
- Decide about the tuck honestly. If you use a separate bedspread or fold the quilt at the foot, set the tuck to zero and the quilt gets a lot smaller — and cheaper.
- Bunk and daybeds want less drop. A quilt that hangs to the floor on a top bunk is a hazard and a nuisance. Set the hang negative territory by reducing it to zero and trimming the depth to where you want it to stop.
How to use
- Pick the bed and measure the mattress depth — made up, with the sheets on.
- Set how far below the mattress you want it to hang.
- Set the pillow tuck, or zero if you fold the quilt at the foot.
- Note that the quilt is not centred — it sits further up or down the bed.
Frequently asked questions
How big should a quilt be for a queen bed?
It depends entirely on the mattress depth, which is the number the standard sizes get wrong. Width is the mattress plus twice the drop, where the drop is the depth plus however far below the edge you want it to hang. On a 14-inch mattress with a 2-inch hang, a queen wants 92 inches wide against the 90 usually quoted.
Why is my quilt too small for the bed?
Almost certainly the mattress depth. Standard quilt sizes assume a mattress about 13 to 14 inches deep, and mattresses are now routinely 14 to 18 with a pillow top. Checking every bed against a realistic range of depths, 14 of 30 combinations leave the quilt short of the rail — the worst by five inches a side.
How do I work out the quilt length?
Mattress length plus one drop at the foot plus a pillow tuck. Those are three separate things and only the first is the mattress. A twin on an ordinary 11-inch mattress needs 98 inches against a standard 90 — and every bed-and-depth combination checked comes up short in length, including a queen on a modest mattress.
Is a quilt centred on the bed?
No, and this surprises people. There is a tuck at the head and only a drop at the foot, so the two ends are different — a correctly sized quilt sits further up or down the bed than centred. Mark the centre line with a pin before you put it on, because it will look wrong until you check.
How much should a quilt hang below the mattress?
Two inches is a common choice for a quilt used with a bed skirt or on a divan. Hanging to the floor needs a much bigger quilt and is really a bedspread. On a bunk or a daybed, less is better — a quilt that trails is a hazard.
Do I need a pillow tuck?
Only if the quilt folds back over the pillows. If you use a separate spread, or fold the quilt at the foot of the bed, set the tuck to zero and the quilt gets substantially smaller — often eight or ten inches, which is real fabric and real quilting time.
Where do I measure the mattress depth?
At a corner, with everything on that will be under the quilt — protector, fitted sheet, and especially a topper, which can add several inches. Measure what the quilt actually has to go over, not what the mattress label says.
Should I design the quilt around whole blocks?
It usually works better to get close with whole blocks and then close the gap with a border, which the tool works out. Forcing an exact size out of blocks alone means either an awkward block size or partial blocks at the edges.
Does this send anything anywhere?
No. Everything is calculated in your browser and nothing is stored or uploaded.
🔒 This tool runs entirely in your browser. Nothing you enter is uploaded, logged, or stored.