Data
UK filament price index: September 2026
In September 2026 the median PLA spool cost £12.99/kg, unchanged on August, across 397 listings. Across all filament the median was £14.99/kg, unchanged on August.
- all filament, median
- £14.99/kg
- materials ranked
- 29
- listings
- 2,576
- figures as of
- 6 Oct 2026
From 2,576 filament listings on Amazon UK and Eryone UK, as of 6 Oct 2026. Updated every night.
Key findings, September 2026
- All filament: a median of £14.99/kg in September 2026, unchanged on August.
- PETG Dual/Tri was the cheapest material per kg (median £11.04); Nylon the dearest (£49.99).
- PETG-CF moved most: down 12.6% like for like on August.
- The cheapest PLA brand per kg was SUNLU, at a median of £8.00, 38% below the PLA median.
- Black Friday 2025 (20 Nov 2025 to 1 Dec 2025) was the deepest sale: filament prices fell a median 5.3% below their usual price, and 57% of listings were at least 5% off.
- Multi-packs of PLA cost a median £10.00/kg, 26% less than single spools.
Filament price leaderboard, September 2026
Every material with enough listings, cheapest median per kg first, against the all-filament benchmark. Switch tabs for buying and bulk figures.
What a kilogram of each material typically costs, and which way it's moving.
| 12-month trend | |||||||
|---|---|---|---|---|---|---|---|
| Benchmark, not ranked | All filament | £14.99 | unchanged0.0% | down1.1% | — | 2,576 | |
| Rank 1 | PETG Dual/Tri | £11.04 | down7.9% | down5.0% | — | 11 | |
| Rank 2 | PETG | £12.74 | up2.0% | down0.1% | — | 284 | |
| Rank 3 | PLA Matte Twist | £12.74 | unchanged0.0% | up0.3% | — | 13 | |
| Rank 4 | PLA | £12.99 | unchanged0.0% | down0.7% | — | 397 | |
| Rank 5 | PLA Matte | £13.99 | down4.7% | down1.6% | — | 290 | |
| Rank 6 | PLA Translucent | £13.99 | up7.7% | down0.3% | — | 31 | |
| Rank 7 | PETG Translucent | £13.99 | up7.7% | up4.0% | — | 29 | |
| Rank 8 | PLA Rainbow | £13.99 | unchanged0.0% | up0.4% | — | 29 | |
| Rank 9 | PLA+ | £14.00 | unchanged0.0% | down0.5% | — | 299 | |
| Rank 10 | PLA Silk | £14.99 | unchanged0.0% | down1.6% | — | 141 | |
| Rank 11 | PLA Silk Dual/Tri | £15.99 | unchanged0.0% | down1.6% | — | 322 | |
| Rank 12 | PLA Glitter | £15.99 | down5.9% | down0.7% | — | 153 | |
| Rank 13 | PLA Matte Gradient | £15.99 | down5.9% | down3.6% | — | 48 | |
| Rank 14 | PLA Silk Twist | £16.66 | down10.7% | down2.4% | — | 10 | |
| Rank 15 | PLA Glow | £16.99 | unchanged0.0% | down2.1% | — | 78 | |
| Rank 16 | PLA Silk Rainbow | £16.99 | down5.6% | down2.4% | — | 76 | |
| Rank 17 | PLA Marble | £16.99 | unchanged0.0% | down1.9% | — | 34 | |
| Rank 18 | PLA Matte Rainbow | £17.56 | down12.1% | down3.2% | — | 38 | |
| Rank 19 | PETG-CF | £17.84 | down18.9% | down12.6% | — | 7 | |
| Rank 20 | PLA Matte Dual/Tri | £17.99 | unchanged0.0% | down0.5% | — | 90 | |
| Rank 21 | PLA Silk Gradient | £19.99 | unchanged0.0% | down1.3% | — | 21 | |
| Rank 22 | PLA Wood | £20.40 | down9.3% | down4.5% | — | 18 | |
| Rank 23 | PLA+ Silk | £21.99 | — | — | — | — | 9 |
| Rank 24 | ASA | £22.99 | down11.5% | down2.0% | — | 37 | |
| Rank 25 | ABS-CF | £22.99 | unchanged0.0% | unchanged0.0% | — | 10 | |
| Rank 26 | ABS | £23.99 | unchanged0.0% | down1.0% | — | 29 | |
| Rank 27 | TPU | £26.92 | down13.1% | unchanged0.0% | — | 56 | |
| Rank 28 | Carbon Fiber | £35.54 | unchanged0.0% | down3.2% | — | 5 | |
| Rank 29 | Nylon | £49.99 | unchanged0.0% | unchanged0.0% | — | 8 |
Ranked by median price per kg, cheapest first; "All filament" is every material together. The bar marks the median within the middle half of listings. "vs last month" compares medians; "like for like" follows the same listings in both months; "vs a year ago" compares the median with the same month last year. Highlighted cells are the best in each column. Materials need 5 listings to be ranked; tap a heading to sort.
What counts as a good price, and whether now is a good time to buy.
| Shop | |||||||
|---|---|---|---|---|---|---|---|
| Benchmark, not ranked | All filament | £11.99/kg | About usualunchanged0.0% | £14.44 – £15.99 | — | −5.3% Black Friday 2025 | Every material |
| Rank 1 | PETG Dual/Tri | £10.62/kg | Cheaper than usualdown7.9% | £10.19 – £11.99 | XINGTONGZHILIAN £11.04/kg | −0.0% Prime Big Deal Days 2025 | PETG Dual/Tri deals |
| Rank 2 | PETG | £9.99/kg | About usualdown0.4% | £11.99 – £12.99 | YUANEANG £8.17/kg | −12.9% Black Friday 2025 | PETG deals |
| Rank 3 | PLA Matte Twist | £11.04/kg | Cheaper than usualdown8.9% | £11.01 – £15.20 | ERYONE £11.52/kg | −10.3% Black Friday 2025 | PLA Matte Twist deals |
| Rank 4 | PLA | £10.62/kg | About usualunchanged0.0% | £12.74 – £13.59 | SUNLU £8.00/kg | −5.0% Black Friday 2025 | PLA deals |
| Rank 5 | PLA Matte | £11.42/kg | About usualdown3.0% | £13.29 – £14.99 | Deeplee £11.00/kg | −8.2% Black Friday 2025 | PLA Matte deals |
| Rank 6 | PLA Translucent | £11.99/kg | About usualunchanged0.0% | £12.99 – £15.99 | ZIRO £12.99/kg | −5.0% Black Friday 2025 | PLA Translucent deals |
| Rank 7 | PETG Translucent | £11.50/kg | Cheaper than usualdown4.7% | £12.99 – £16.99 | SUNLU £8.92/kg | −15.0% Black Friday 2025 | PETG Translucent deals |
| Rank 8 | PLA Rainbow | £12.99/kg | Dearer than usualup4.7% | £12.99 – £14.36 | YUANEANG £12.99/kg | −6.3% Black Friday 2025 | PLA Rainbow deals |
| Rank 9 | PLA+ | £12.00/kg | About usualdown2.7% | £13.59 – £15.89 | JAYO £11.89/kg | −5.1% Black Friday 2025 | PLA+ deals |
| Rank 10 | PLA Silk | £12.99/kg | About usualunchanged0.0% | £14.98 – £15.99 | NevsBye £9.99/kg | −0.0% Black Friday 2025 | PLA Silk deals |
| Rank 11 | PLA Silk Dual/Tri | £13.01/kg | Cheaper than usualdown5.9% | £15.99 – £17.99 | YUANEANG £11.99/kg | −15.0% Black Friday 2025 | PLA Silk Dual/Tri deals |
| Rank 12 | PLA Glitter | £12.31/kg | About usualunchanged0.0% | £15.92 – £16.99 | eSUN £8.77/kg | −3.9% Black Friday 2025 | PLA Glitter deals |
| Rank 13 | PLA Matte Gradient | £14.99/kg | Cheaper than usualdown5.9% | £15.99 – £17.99 | FLASHFORGE £14.38/kg | −0.0% Black Friday 2025 | PLA Matte Gradient deals |
| Rank 14 | PLA Silk Twist | £12.17/kg | Cheaper than usualdown5.3% | £15.14 – £21.99 | ERYONE £11.89/kg | −0.0% Prime Big Deal Days 2025 | PLA Silk Twist deals |
| Rank 15 | PLA Glow | £14.43/kg | Cheaper than usualdown5.6% | £15.99 – £18.99 | JAYO £13.96/kg | −0.0% Black Friday 2025 | PLA Glow deals |
| Rank 16 | PLA Silk Rainbow | £14.99/kg | Cheaper than usualdown5.6% | £16.99 – £19.99 | YUANEANG £9.85/kg | −5.0% Prime Big Deal Days 2025 | PLA Silk Rainbow deals |
| Rank 17 | PLA Marble | £14.24/kg | About usualunchanged0.0% | £15.18 – £17.99 | CC3D £14.49/kg | −15.7% Prime Big Deal Days 2025 | PLA Marble deals |
| Rank 18 | PLA Matte Rainbow | £15.99/kg | About usualdown2.4% | £14.99 – £19.99 | ZIRO £14.99/kg | −2.6% Black Friday 2025 | PLA Matte Rainbow deals |
| Rank 19 | PETG-CF | £17.84/kg | Cheaper than usualdown15.0% | £14.95 – £21.99 | ERYONE £17.84/kg | −6.3% Prime Big Deal Days 2025 | PETG-CF deals |
| Rank 20 | PLA Matte Dual/Tri | £14.99/kg | About usualunchanged0.0% | £15.99 – £17.99 | R3D £10.59/kg | −10.0% Black Friday 2025 | PLA Matte Dual/Tri deals |
| Rank 21 | PLA Silk Gradient | £16.99/kg | Dearer than usualup11.1% | £16.64 – £19.99 | OVERTURE £19.99/kg | −5.6% Black Friday 2025 | PLA Silk Gradient deals |
| Rank 22 | PLA Wood | £13.69/kg | About usualdown2.8% | £17.34 – £22.49 | LVVJ3D £20.40/kg | −5.6% Black Friday 2025 | PLA Wood deals |
| Rank 23 | PLA+ Silk | £15.99/kg | — | — | SUNLU £15.12/kg | — | PLA+ Silk deals |
| Rank 24 | ASA | £16.99/kg | Cheaper than usualdown4.2% | £20.34 – £25.99 | ANYCUBIC £14.59/kg | −12.2% Black Friday 2025 | ASA deals |
| Rank 25 | ABS-CF | £22.99/kg | About usualunchanged0.0% | £22.99 – £22.99 | ERYONE £22.99/kg | — | ABS-CF deals |
| Rank 26 | ABS | £11.39/kg | About usualunchanged0.0% | £17.98 – £23.99 | YUANEANG £9.99/kg | −6.7% Black Friday 2025 | ABS deals |
| Rank 27 | TPU | £17.74/kg | Cheaper than usualdown13.1% | £26.92 – £30.99 | Sovol £13.99/kg | — | TPU deals |
| Rank 28 | Carbon Fiber | £25.99/kg | About usualunchanged0.0% | £35.54 – £35.54 | ERYONE £35.54/kg | — | Carbon Fiber deals |
| Rank 29 | Nylon | £26.99/kg | About usualunchanged0.0% | £49.99 – £49.99 | ERYONE £49.99/kg | — | Nylon deals |
Ranked by median price per kg, cheapest first; "All filament" is every material together. "Good price" is the 25th percentile: cheaper than three in four listings. "Now vs usual" compares this month's median with the median of the months before it (up to a year); within ±3% counts as usual. "Best sale" is the deepest median discount in the last year. Highlighted cells are the best in each column. Materials need 5 listings to be ranked; tap a heading to sort, or filter "Now vs usual".
Multi-packs against single spools, cost per 100 g for quoting, and how much prices swing over a year.
| Benchmark, not ranked | All filament | £15.99 | £10.00 | down37.5% | 405 | £1.50 | 10.7% |
|---|---|---|---|---|---|---|---|
| Rank 1 | PETG Dual/Tri | £11.04 | — | — | — | £1.10 | 17.7% |
| Rank 2 | PETG | £13.99 | £9.17 | down34.5% | 72 | £1.27 | 8.3% |
| Rank 3 | PLA Matte Twist | £12.74 | — | — | — | £1.27 | 38.1% |
| Rank 4 | PLA | £13.59 | £10.00 | down26.4% | 107 | £1.30 | 6.7% |
| Rank 5 | PLA Matte | £14.99 | £10.00 | down33.3% | 71 | £1.40 | 12.8% |
| Rank 6 | PLA Translucent | £13.99 | — | — | 1 | £1.40 | 23.1% |
| Rank 7 | PETG Translucent | £14.99 | £10.75 | down28.3% | 6 | £1.40 | 30.8% |
| Rank 8 | PLA Rainbow | £13.99 | £12.69 | down9.3% | 4 | £1.40 | 10.5% |
| Rank 9 | PLA+ | £15.15 | £10.00 | down34.0% | 76 | £1.40 | 16.9% |
| Rank 10 | PLA Silk | £14.99 | £11.05 | down26.3% | 19 | £1.50 | 6.7% |
| Rank 11 | PLA Silk Dual/Tri | £15.99 | £16.74 | up4.7% | 16 | £1.60 | 12.5% |
| Rank 12 | PLA Glitter | £15.99 | £16.24 | up1.6% | 4 | £1.60 | 6.7% |
| Rank 13 | PLA Matte Gradient | £15.99 | — | — | — | £1.60 | 12.5% |
| Rank 14 | PLA Silk Twist | £16.66 | — | — | — | £1.67 | 45.2% |
| Rank 15 | PLA Glow | £16.99 | £18.99 | up11.8% | 9 | £1.70 | 18.8% |
| Rank 16 | PLA Silk Rainbow | £16.99 | £16.50 | down2.9% | 9 | £1.70 | 17.7% |
| Rank 17 | PLA Marble | £16.99 | — | — | — | £1.70 | 18.5% |
| Rank 18 | PLA Matte Rainbow | £17.63 | — | — | 1 | £1.76 | 33.4% |
| Rank 19 | PETG-CF | £17.84 | — | — | — | £1.78 | 47.1% |
| Rank 20 | PLA Matte Dual/Tri | £17.99 | — | — | 1 | £1.80 | 12.5% |
| Rank 21 | PLA Silk Gradient | £19.99 | — | — | — | £2.00 | 20.1% |
| Rank 22 | PLA Wood | £20.40 | — | — | — | £2.04 | 29.7% |
| Rank 23 | PLA+ Silk | £15.99 | £49.36 | up208.7% | 4 | £2.20 | — |
| Rank 24 | ASA | £22.99 | — | — | — | £2.30 | 27.8% |
| Rank 25 | ABS-CF | £22.99 | — | — | — | £2.30 | 0.0% |
| Rank 26 | ABS | £23.99 | — | — | 1 | £2.40 | 33.4% |
| Rank 27 | TPU | £27.99 | £14.50 | down48.2% | 4 | £2.69 | 15.1% |
| Rank 28 | Carbon Fiber | £35.54 | — | — | — | £3.55 | 0.0% |
| Rank 29 | Nylon | £49.99 | — | — | — | £5.00 | 0.0% |
Ranked by median price per kg, cheapest first; "All filament" is every material together. Multi-packs include spools of 2 kg or more. Each figure needs three listings. "Per 100 g" is the filament in a 100 g print at the median price. "12-month swing" is how far the monthly median moved between its low and high. Highlighted cells are the best in each column. Materials need 5 listings to be ranked; tap a heading to sort.
How prices moved
The four materials with the most listings and the all-filament benchmark, month by month.
Cheapest brands per kg
The brands with the lowest median price per kg in September 2026, by material.
| Rank 1 | SUNLU | £8.00/kg | down38.4% | 10 |
|---|---|---|---|---|
| Rank 2 | OVERTURE | £9.99/kg | down23.1% | 24 |
| Rank 3 | YUANEANG | £9.99/kg | down23.1% | 12 |
| Rank 4 | LANDU | £10.72/kg | down17.5% | 12 |
| Rank 5 | 3DHoJor | £10.99/kg | down15.4% | 5 |
| Rank 6 | JAYO | £11.00/kg | down15.3% | 12 |
| Rank 7 | eSUN | £11.50/kg | down11.5% | 39 |
| Rank 8 | ANYCUBIC | £12.99/kg | unchanged0.0% | 73 |
| Rank 9 | Kingroon | £12.99/kg | unchanged0.0% | 28 |
| Rank 10 | ELEGOO | £13.59/kg | up4.6% | 42 |
| Rank 1 | YUANEANG | £11.99/kg | down25.0% | 12 |
|---|---|---|---|---|
| Rank 2 | Sovol | £12.44/kg | down22.2% | 3 |
| Rank 3 | NevsBye | £13.13/kg | down17.9% | 12 |
| Rank 4 | 3DHoJor | £13.99/kg | down12.5% | 14 |
| Rank 5 | ANYCUBIC | £14.99/kg | down6.3% | 13 |
| Rank 6 | RepRapper | £14.99/kg | down6.3% | 9 |
| Rank 7 | GratKit | £15.99/kg | unchanged0.0% | 19 |
| Rank 8 | LANDU | £15.99/kg | unchanged0.0% | 13 |
| Rank 9 | R3D | £15.99/kg | unchanged0.0% | 20 |
| Rank 10 | SUNLU | £15.99/kg | unchanged0.0% | 18 |
| Rank 1 | JAYO | £11.89/kg | down15.1% | 20 |
|---|---|---|---|---|
| Rank 2 | SUNLU | £12.99/kg | down7.2% | 90 |
| Rank 3 | NevsBye | £13.08/kg | down6.6% | 2 |
| Rank 4 | eSUN | £13.91/kg | down0.6% | 52 |
| Rank 5 | ANYCUBIC | £13.99/kg | down0.1% | 21 |
| Rank 6 | RepRapper | £14.39/kg | up2.8% | 2 |
| Rank 7 | ELEGOO | £15.99/kg | up14.2% | 9 |
| Rank 8 | OVERTURE | £15.99/kg | up14.2% | 44 |
| Rank 9 | FLASHFORGE | £16.19/kg | up15.6% | 14 |
| Rank 10 | ERYONE | £23.99/kg | up71.4% | 42 |
| Rank 1 | Deeplee | £11.00/kg | down21.4% | 46 |
|---|---|---|---|---|
| Rank 2 | NevsBye | £11.33/kg | down19.0% | 9 |
| Rank 3 | eSUN | £11.38/kg | down18.7% | 28 |
| Rank 4 | JAYO | £12.99/kg | down7.1% | 9 |
| Rank 5 | YUANEANG | £12.99/kg | down7.1% | 3 |
| Rank 6 | SUNLU | £13.31/kg | down4.9% | 39 |
| Rank 7 | ANYCUBIC | £13.44/kg | down3.9% | 12 |
| Rank 8 | ELEGOO | £13.59/kg | down2.9% | 11 |
| Rank 9 | iSANMATE | £13.99/kg | unchanged0.0% | 2 |
| Rank 10 | ZIRO | £13.99/kg | unchanged0.0% | 17 |
| Rank 1 | YUANEANG | £8.17/kg | down35.9% | 14 |
|---|---|---|---|---|
| Rank 2 | TECBEARS | £8.99/kg | down29.4% | 18 |
| Rank 3 | LANDU | £9.70/kg | down23.9% | 8 |
| Rank 4 | NevsBye | £9.94/kg | down22.0% | 2 |
| Rank 5 | SUNLU | £10.00/kg | down21.5% | 15 |
| Rank 6 | XINGTONGZHILIAN | £10.99/kg | down13.7% | 11 |
| Rank 7 | GratKit | £11.11/kg | down12.8% | 16 |
| Rank 8 | Sovol | £11.47/kg | down10.0% | 8 |
| Rank 9 | JAYO | £11.99/kg | down5.9% | 9 |
| Rank 10 | Kingroon | £12.25/kg | down3.8% | 8 |
| Rank 1 | eSUN | £8.77/kg | down45.2% | 9 |
|---|---|---|---|---|
| Rank 2 | OVERTURE | £13.99/kg | down12.5% | 4 |
| Rank 3 | ZIRO | £13.99/kg | down12.5% | 28 |
| Rank 4 | TINMORRY | £15.99/kg | unchanged0.0% | 4 |
| Rank 5 | FLASHFORGE | £16.99/kg | up6.3% | 4 |
| Rank 6 | ELEGOO | £17.99/kg | up12.5% | 12 |
| Rank 7 | ERYONE | £17.99/kg | up12.5% | 73 |
| Rank 8 | ANYCUBIC | £19.99/kg | up25.0% | 4 |
| Rank 9 | chitu systems | £21.08/kg | up31.8% | 4 |
| Rank 10 | Stronghero3D | £21.41/kg | up33.9% | 6 |
| Rank 1 | NevsBye | £9.99/kg | down33.4% | 4 |
|---|---|---|---|---|
| Rank 2 | ZIRO | £13.49/kg | down10.0% | 16 |
| Rank 3 | LANDU | £13.99/kg | down6.7% | 3 |
| Rank 4 | SUNLU | £13.99/kg | down6.7% | 29 |
| Rank 5 | OVERTURE | £14.44/kg | down3.7% | 9 |
| Rank 6 | ANYCUBIC | £14.99/kg | unchanged0.0% | 10 |
| Rank 7 | JAYO | £14.99/kg | unchanged0.0% | 3 |
| Rank 8 | AMOLEN | £15.12/kg | up0.9% | 2 |
| Rank 9 | ELEGOO | £15.99/kg | up6.7% | 13 |
| Rank 10 | Eono | £19.99/kg | up33.4% | 3 |
| Rank 1 | R3D | £10.59/kg | down41.1% | 5 |
|---|---|---|---|---|
| Rank 2 | eSUN | £14.07/kg | down21.8% | 2 |
| Rank 3 | GratKit | £14.99/kg | down16.7% | 7 |
| Rank 4 | ZIRO | £14.99/kg | down16.7% | 12 |
| Rank 5 | OVERTURE | £15.60/kg | down13.3% | 4 |
| Rank 6 | SUNLU | £15.99/kg | down11.1% | 8 |
| Rank 7 | ERYONE | £26.99/kg | up50.0% | 46 |
| Rank 8 | Goto Guard | £35.06/kg | up94.9% | 3 |
Every month's brand ranking is in the brands CSV.
How deep were the sales?
Prime Day, Black Friday and other events in the last year, ranked by how far prices really fell.
| By material | ||||
|---|---|---|---|---|
| Rank 1 | Black Friday 202520 Nov 2025 to 1 Dec 2025 · 1628 listings | 5.3%all filament | 57% |
|
| Rank 2 | Prime Big Deal Days 20257 Oct 2025 to 8 Oct 2025 · 1283 listings | 0.0%all filament | 45% |
|
The discount is each listing's lowest price during the event against its own median over the 30 days before, from our price history, not the retailer's "was" price.
Filament prices: common questions
Answers from the September 2026 figures.
How much does PLA filament cost in the UK?
In September 2026 the median PLA listing on Amazon UK and Eryone UK cost £12.99/kg, and the middle half of listings cost between £10.62 and £14.99 per kg. That's from 397 listings in SpoolDeal's price index, as of 30 Sept 2026.
What is a good price for PLA filament per kg?
Under £10.62/kg is cheaper than three in four PLA listings we track (September 2026). The cheapest brand per kg was SUNLU, at a median of £8.00/kg. Compare by price per kg, not per spool: spool sizes and multi-packs vary.
Is 3D printer filament getting cheaper?
Across all filament the median was £14.99/kg in September 2026, unchanged on the month before. Like for like, following the same listings, prices were down 1.1%.
Are filament multi-packs cheaper than single spools?
PLA multi-packs cost £10.00/kg, 26% less than single spools (£13.59/kg); PLA Silk Dual/Tri multi-packs cost about the same per kg as single spools (£16.74/kg); PLA+ multi-packs cost £10.00/kg, 34% less than single spools (£15.15/kg), in September 2026.
How much do filament prices really drop on Prime Day and Black Friday?
Black Friday 2025: prices fell a median 5.3% below their usual price, with 57% of listings at least 5% off. Prime Big Deal Days 2025: prices barely moved from their usual price, with 45% of listings at least 5% off. The usual price is each listing's own median over the 30 days before the event, from our price history, not the retailer's "was" price.
Can I use these figures?
Yes. The index and its CSV are free to reuse under CC BY 4.0: credit "SpoolDeal UK filament price index" and link to the month's page. Press and data questions: james@trinkify.co.uk.
Every month
Each month keeps its own page, so a figure you quote stays where you found it.
Methodology
What's covered. The filament listings SpoolDeal tracks on Amazon UK and Eryone UK, not every UK shop. We check prices through the day and keep every change, so each listing has a price for every day: the one in effect at noon (UTC). It's the lowest price on offer, including Prime members' prices where those are lower, with VAT. Dividing by the filament weight on the listing (a multi-pack counts every spool) gives a price per kilogram.
How a month is worked out. A listing's price for a month is the median of its days; it needs at least seven days of prices. A material's figure is the median across its listings, and "All filament" is the median across every listing. Listings under £4/kg or over £250/kg are left out as mispriced. Materials are grouped as the listings name them (PLA, PLA+, PLA Silk and so on).
Change. "vs last month" and "vs a year ago" compare medians, so they move when listings come and go. "Like for like" follows only the listings priced in both months: the geometric mean of each listing's own change, the method the ONS uses for the Consumer Prices Index. "Now vs usual" compares a month's median with the median of the months before it, up to a year.
Brands, multi-packs and sales. A brand is ranked on the median of its listings of that material (at least two). Multi-packs include single spools of 2 kg or more; the single-spool and multi-pack figures each need three listings. A sales event's discount compares each listing's lowest price during the event with its own median over the 30 days before (at least 14 days of prices); it never uses the retailer's "was" price. Event dates are the retailer's announced dates.
Revisions. The last 13 months are recomputed every night from the full history, so the running month is provisional and a recent month can shift slightly as late price changes arrive. Older months are frozen, and every month keeps its own page.
Reuse. Free under CC BY 4.0: credit "SpoolDeal UK filament price index" with a link to the month's page. Data: materials CSV and brands CSV. Questions: james@trinkify.co.uk.
Waiting for cheaper filament?
Open any reel and set the price you want to pay. We check it through the day and email you when it gets there. Free, and you can switch it off any time.