Resin vs Filament: Real Cost Per Print, Not Per Kilogram

The short answer

Resin vs filament cost comes down to cost per print, not cost per kilogram. A 16 g PLA+ keychain uses roughly ₹15–₹27 of filament at Indian spool prices; the same shape in resin costs about ₹35–₹72 once supports, waste and alcohol are counted. Filament wins on a single part. Resin closes the gap when one plate carries twenty identical small parts.

Why cost per kilogram is the wrong number

A spool price is a shelf price, not a part price. Two things break the tidy conversion between them:

1. You never print the whole spool. Brims, purge lines, supports, failed first layers and colour changes all consume material that never reaches the finished part.
2. Resin arrives with a supporting cast. The bottle is only part of the consumable list — isopropyl alcohol (IPA), nitrile gloves, paper towels and a UV cure step all sit on the same invoice.

The Fused filament fabrication reference describes the trade-off bluntly: alternative processes such as photopolymerisation "may offer better results, but they are much more costly." The word that matters is may. Resin is expensive per kilogram and superb at fine detail. Whether it is expensive per part depends entirely on how you pack the build plate.

Resin vs filament cost: the numbers side by side

Those bands are wide because prices move with brand, colour, pack size and shipping. Treat them as a starting range and check the live listing before you commit — the useful habit is to model the part, not the shelf.

Material choice moves the number as much as process does. The 3D printer filament comparison chart sets PLA, PETG, TPU, ABS and ASA against each other on the properties that decide whether a part survives its first year, and price per kilogram is only one column in it.

What a 16 g keychain actually costs

Nuho India prints PLA+ keychains at around 215 °C, in the 14–18 g range, manufacturing and despatching within 24–48 hours from Coimbatore, Tamil Nadu. Take a mid-range 16 g name tag and run both processes honestly:

The headline survives: roughly ₹20 of material for filament against ₹40–₹80 for resin on the same part. Resin's per-part material cost is higher even though its machine time per part can be dramatically lower, because a resin plate holds dozens of small parts at once while an FFF plate prints them one at a time or in a slow row.

If you sell a product rather than a hobby, that gap is the whole margin. It is also why a printed keychain can retail at ₹129–₹149: our breakdown of 3D printed keychain prices in India shows how little of that figure is material. At those PLA+ material costs, the letterforms are fused to a continuous backing plate rather than glued on, which is where the value actually sits.

Where resin quietly costs more than the bottle

• The wash. Every print needs IPA, and the IPA becomes saturated and must eventually be replaced. Budget ₹5–₹12 per small part, more for large hollow ones.
• The cure. A UV station adds electricity and time, and it is not optional — an under-cured part stays soft and smells.
• The FEP film. The transparent film at the bottom of the tank is a wear item. It scratches, clouds and eventually tears, and it is a recurring cost with no filament equivalent.
• The safety kit. Resin is a skin sensitiser. Gloves, ventilation and a dedicated workspace are part of the cost of entry, not optional extras.
• Plate-level failure. A support failure at hour four can ruin every part on the plate. On an FFF machine the same mistake usually ruins one part.
• Disposal. Waste resin cannot go down a drain. Cured waste goes in the bin; liquid waste needs sunlight or a cure station first.

Wikipedia's page on stereolithography notes the process is fast and can produce almost any design, while still being described as expensive. That is the honest summary: you are buying detail, and the consumables are where you pay for it. Filament has its own honest caveats — our PLA vs PETG durability comparison covers where PLA+ cracks rather than flexes, which is the real limit on a cheap material.

Where filament quietly costs more than the spool

• Print time. A resin plate of twenty miniatures can finish in the time an FFF machine spends on two or three. Time is money if you are the one watching the machine.
• Supports you cannot avoid. Overhangs on a keychain hook or a decor arm need supports that are thrown away. A 10% scrap factor is realistic; 15% is not pessimistic.
• Fine detail. A 0.4 mm nozzle physically cannot resolve a 1 mm letterform as crisply as a light-cured layer. If the product is tiny text, FFF will lose parts to the bin.
• Colour changes. Multi-colour FFF purges a tower between colours, and that tower is paid material that ends up in the bin.
• Nozzle and bed wear. Slow, but real. A brass nozzle printing abrasive filament is a consumable.

Cost per print for five typical jobs

The pattern is not "resin is expensive." It is: resin wins when parts are small, detailed and numerous; filament wins when parts are large, chunky or few.

How to calculate your own cost per print

1. Weigh the finished part on a kitchen scale, in grams.
2. Add your scrap factor — 10–15% for FFF, 20–40% for resin.
3. Multiply by your real cost per gram: spool or bottle price ÷ 1,000.
4. Add consumables honestly: IPA, gloves, FEP film for resin; nozzle and bed surface for filament.
5. Add machine amortisation: printer price ÷ the number of hours you expect from it.
6. Add electricity — small for both, but not zero for a heated bed or a 4-hour resin run.
7. Add your own labour at a rate you would accept from an employer.
8. Repeat the calculation every quarter. Filament and resin prices in India move with imports, and a number you memorised last year is probably wrong.

Which should you buy first?

Filament, in almost every case. The printer is simpler, the material is cheaper per gram, there is no wash-and-cure step, and a mistake costs one part instead of a whole plate. Resin becomes the right second machine the moment your actual work involves miniatures, jewellery-scale detail or batches of small identical parts — not before.

If your product is keychains, tags and decor, the choice is genuinely settled: PLA+ at 215 °C produces a part in the 14–18 g range that is tough, waterproof in normal use and light enough to sit on a bike key without swinging. That is a material-cost problem worth solving with filament.

Prices and specs change — verify with the manufacturer before buying.