Curtain lining calculator
Curtain lining is bought separately from the face fabric and calculated differently: it is plain, so no pattern repeat has to be matched, it comes on a narrower roll — 137 cm is the UK standard — and it is cut short of the face fabric so it cannot show below the hem. Because the roll is narrower, a curtain that took two widths of face fabric can need three of lining. The calculator below takes the flat width your curtains need and solves it again on the lining roll, showing every allowance.
Your curtains and your lining
Allowances, hems and fittings
9.7 m
4 cuts of 242.5 cm, on a 137 cm roll. Rounded up to nearest 10 cm.
- Flat width each curtain needs
- 200 cmset by the face fabric at 2× fullness
- Lining widths per curtain
- 2 widthson a 137 cm roll
- Lining cut length
- 242.5 cm2.5 cm shorter than the face fabric, plus heading and hem
- Total lining before rounding
- 970 cm4 cuts
Line up the lining seams with the face fabric seams where you can. Where the two fall in different places the join shows as a ridge in raking light, particularly on a pale face fabric.
How we got this
- Lining widths per curtain — 2 widths200 cm needed ÷ 137 cm lining, allowing 10 cm of side hems
- Lining cut length — 242.5 cm220 cm drop − 2.5 cm shortfall + 15 cm heading + 10 cm hem
- Lining required — 970 cm4 cuts × 242.5 cm
How this calculator works
Lining is a second purchase with its own arithmetic, and the mistake people make is assuming it follows the face fabric. It does not. Three things differ, and each one pulls in a different direction.
Across: the lining has to reach the same flat width the curtains do, because it is made up into the same curtain. That width comes from the track and the fullness exactly as it does for the face fabric — but it is then divided by the lining roll rather than the fabric roll, and standard UK lining is 137 cm where much furnishing fabric is 140 cm. A narrower roll can need an extra width.
Down: the lining is cut shorter. It gets the same heading allowance, because it is turned down into the same heading, but a shallower single-turned hem and a shortfall so it finishes clear of the face hem and cannot show. Those two together usually make the lining cut shorter than the face cut by rather more than the shortfall alone.
And there is no repeat. Lining is plain, so nothing has to be matched down the roll and no cloth is lost rounding a cut up to the next whole pattern repeat. On a patterned face fabric that alone can make the lining a metre shorter than the fabric it is going behind.
A worked example
A 200 cm track, a 220 cm drop, a pair of curtains at 2× fullness, lined in 137 cm standard lining. These are the calculator's own starting values, so the table below is the same arithmetic the tool runs, not a retelling of it.
| Step | Working | Result |
|---|---|---|
| Lining widths per curtain | 200 cm needed ÷ 137 cm lining, allowing 10 cm of side hems | 2 widths |
| Lining cut length | 220 cm drop − 2.5 cm shortfall + 15 cm heading + 10 cm hem | 242.5 cm |
| Lining required | 4 cuts × 242.5 cm | 970 cm |
Note the cut length: 242.5 cm against a 220 cm finished drop. The heading allowance adds to it and the shortfall takes away, and the lining hem is shallower than a face hem would be — so the lining cut is longer than the drop but shorter than the face fabric's cut would be for the same curtain.
Why the lining roll width matters so much
The width count is a whole number, so the lining roll either reaches the flat width in the same number of widths as the face fabric or it does not. There is no partial answer. On the small window above it makes no difference at all — every common lining roll takes two widths. Widen the window and it decides the bill: below is a 320 cm track at 2.5× fullness, which needs 400 cm of flat cloth in each curtain.
| Lining roll | Widths per curtain | Cuts | Lining to buy |
|---|---|---|---|
| 112 cm | 4 | 8 | 19.4 m |
| 137 cm | 4 | 8 | 19.4 m |
| 140 cm | 3 | 6 | 14.6 m |
| 150 cm | 3 | 6 | 14.6 m |
Three centimetres of roll width — the difference between standard 137 cm lining and a 140 cm one — is a whole extra width per curtain here, and two extra cuts across the pair. That is the same threshold effect the fabric width chart describes for face fabric, and it bites harder on lining because the roll is narrow to begin with. If your supplier offers lining in more than one width, the wider one is worth pricing even at a higher rate per metre.
How to measure for this
- Measure the track. The pole or track the curtains hang from, finials excluded. This is the same figure the face fabric was calculated from.
- Take the finished drop. Hook, ring or eyelet position down to the hem. The lining is worked out from the face fabric’s finished length, not from its cut length.
- Check the lining roll width. Standard UK curtain lining is 137 cm, which is narrower than most furnishing fabric. Measure it rather than assuming it matches.
- Use the same fullness as the curtains. The lining has to reach the same flat width the face fabric does, so it is solved at the fullness the curtains were made to.
- Decide the shortfall. How far short of the face hem the lining finishes so it cannot show. 2.5 cm is normal.
Every figure the calculation adds is editable under Allowances, hems and fittings. The defaults are the middle of the UK curtain-making range: a 15 cm heading allowance, a 10 cm single-turned lining hem, 5 cm side hems, 1.5 cm seams and a 2.5 cm shortfall. If your workroom quotes different numbers, use theirs — the arithmetic is the same either way and the side hems are charged to the two outer edges only.
What this assumes
- Standard lining, not blackout or thermal. Those come in their own widths and are often heavier and stiffer, which changes the heading but not this arithmetic. Enter the roll width you are actually buying.
- No interlining. Interlining is a third layer with its own roll width, no side hems because it is enclosed, and a bulk that changes what the heading consumes. Work it out separately.
- Locked-in lining, not detachable. A detachable lining hangs from its own tape on the same hooks and is made to its own finished width, so it is not solved from the face fabric's flat width at all.
- The lining is plain. Printed or checked lining exists and would need repeat matching, which this does not do — use the pattern repeat calculator for the cut length if yours has one.
- Rounding is always up, at every step, as it is everywhere on this site. Buying too much lining costs a few pounds; buying too little means a second trip and possibly a different dye lot.
For the face fabric itself, including the pattern repeat and the placement allowance, use the curtain fabric calculator — it works out lining alongside the fabric using this same function, so the two tools cannot disagree. To settle how many widths the curtains need in the first place, the curtain fullness calculator shows what each width count really gathers to.
Common questions
- How much lining do I need for a pair of curtains?
- The same flat width as the face fabric, solved again on the lining roll. Because standard UK lining is 137 cm and much furnishing fabric is 140 cm, the lining sometimes needs an extra width per curtain that the face fabric did not. The length is slightly less, because lining is cut short of the hem.
- Why is the lining cut shorter than the curtain?
- So it cannot peep below the hem when the curtain hangs. A shortfall of about 2.5 cm is normal — enough that the lining stays hidden as the face fabric settles and drops over the first few weeks, and not so much that the lining pulls the hem up.
- Can I use the same fabric width for lining as for the curtains?
- Only if that is what your supplier sells. Curtain lining is woven for the job at 137 cm and is not usually offered in the widths furnishing fabric comes in. Enter what your roll actually measures rather than assuming it matches the face fabric — the width is what decides the number of widths.
- Should the lining seams line up with the face fabric seams?
- Where you can, yes. Two sets of joins in different places show as ridges in raking light, particularly through a pale face fabric. Where the widths do not divide the same way — which is exactly what happens when the two rolls are different widths — place the lining seams as close to the face seams as the cloth allows.
- Does interlining change the calculation?
- Yes, and this tool does not model it. Interlining is a third layer between face and lining, cut to its own width and usually without side hems because it is enclosed. It also adds bulk that changes how much the heading consumes. Calculate it separately against its own roll width.
Related tools
Curtain fabric calculator
Track width, drop, fullness and pattern repeat in; metres or yards to buy out, with every allowance adjustable.
Curtain fullness calculator
How many widths each curtain needs at the fullness you want — and what whole widths really gather to.
Curtain heading types
Five headings compared on fullness, allowance and what they cost in cloth.
Fabric width chart
Standard roll widths in both systems, and the gap between the label and the cloth.
Pattern repeat calculator
The cut length a repeat forces, what is trimmed from every piece, and what matching the design costs.