Two to three machines: 144–216ml a year. Buy the 300ml at ₹1,799.
Four machines: about 288ml a year — the 300ml is almost exactly one year.
Testing, or a minor room: a 15ml at ₹299.
2. One machine: the 100ml at ₹999. It is about ₹10 a millilitre and roughly sixteen months of supply, which is a sensible horizon. A 300ml on a single machine is closer to four years — the rate is better and the fit is wrong, because very few people run the same fragrance for four years.
3. Two to four machines: the 300ml at ₹1,799. Two machines get through 144ml a year, three 216ml, four 288ml. At 300ml the bottle lasts from about twelve to twenty-five months depending on where you sit in that range, at about ₹6 a millilitre — the best rate available and the right duration.
4. Five or more machines, or heavy use: two bottles a year. Five machines at ordinary use is 360ml a year; three machines run hard — six drops, two fills a day — is about 648ml. At that level buy a 300ml twice a year, or a 300ml plus a 100ml, and stop worrying about it.
5. The 15ml has one job and does it well. Testing. At ₹299 for roughly seventy-five tank-fills it is a proper two-month trial, not a sniff, and being wrong costs almost nothing. It is also the right size for a minor room that runs an hour a week. What it is not is a standing supply — at about ₹20 a millilitre it is three times the rate of the large bottle for identical liquid.
Made in India, composed by an ISIPCA Versailles-trained perfumer — and a portion of every order supports girl-child education through Nanhi Kali.
Why the cheapest rate is not automatically the right size
Price per millilitre is a real number and it is not the deciding one, because fragrance is bought against a time horizon rather than a stockpile. A 300ml at ₹1,799 holds somewhere around fifteen hundred tank-fills at four drops each. On a single machine used once a day that is about four years. Almost nobody runs the same fragrance for four years — people move house, change the machine from a living room to a bedroom, get a dog, discover a scent they like better, or simply tire of one they have stopped noticing. Buying four years of anything at once is not thrift; it is storage with a favourable unit price attached.
The right rule is to buy the bottle that runs out in roughly twelve months, and the arithmetic that gets you there is one line: machines × 6ml × 12. One machine is 72ml a year, which is the 100ml at ₹999 with a few months in hand. Three machines is 216ml, four is 288ml — and 288ml against a 300ml bottle is as close to a year as this category gets. That is the honest reason the large bottle exists: it is sized for a whole home, not for a single room, and it is only the obvious buy once you have three or four machines running. Underneath both figures sits the fact that makes any of this bearable — even at the worst rate in the range, running a machine daily from 15ml bottles is about ₹120 a month, and at the best it is about ₹36. No choice you make here will cost you real money. It will only decide whether you own a bottle you are still using or one you are politely storing.
The three sizes and the job each one does
Hotel CollectionFrom ₹299About ₹20 a millilitre, and roughly seventy-five tank-fills at four drops — two to three months on one machine, which is more than enough to judge a fragrance properly in the room it is meant for. Every Sukoon ships with three of your choice, so most homes begin with a small stock they did not pay for. Beyond testing, the 15ml earns its place in a minor room that runs an hour a week and in seasonal changes — something brighter through a Pune summer, something warmer in December. What it should never be is the bottle you reorder every ten weeks.Every size, rated for what it is actually good at
Fill counts assume four drops a tank at roughly twenty drops to the millilitre. The last column is the one to read — the rate matters far less than whether the bottle matches your machine count.
| Size | Price · rate | Fills · how long on one machine | Right for |
|---|---|---|---|
| 15ml | ₹299 · ≈ ₹20/ml | ~75 fills · about 2½ months | Testing a scent, a minor room, a seasonal change |
| 100ml ★ | ₹999 · ≈ ₹10/ml | ~500 fills · about 16 months | A one-machine home, or the second scent in a larger one |
| 300ml ★ | ₹1,799 · ≈ ₹6/ml | ~1,500 fills · about four years | Two to four machines running the same signature scent |
| Pack of 7 | ₹1,799 · ≈ ₹17/ml | 105ml, ~525 fills across seven scents | Choosing, once — ₹2,093 bought singly |
| Included with a Sukoon | 3 × 15ml, free with the machine | ~225 fills | The first few months of any new setup |
| The rule the table is hiding: a bottle should run out in about a year. On one machine the 300ml lasts roughly four, which is why the cheapest rate in the range is the wrong buy for a single-room home — and exactly right once three or four machines are sharing it. | |||
300ml · the whole-home bottle₹1,799Shop → 
Sukoon · three 15ml included₹1,899Shop → 
Boond · the small rooms₹899Shop →
Working out your own millilitres a year
The whole calculation is one line and it takes a minute. A drop from a dropper bottle is roughly a twentieth of a millilitre, so four drops is about 0.2ml — the dose most households settle on once the first fortnight has passed. One fill a day is 6ml a month and 72ml a year per machine. Count your machines, multiply, and you have your annual figure: two machines 144ml, three 216ml, four 288ml, five 360ml. If you run six drops and two fills a day, triple it — one machine becomes 216ml a year and three become 648ml, which is two 300ml bottles.
Then adjust for how the rooms are actually used, because machine count overstates consumption in most homes. Bedrooms tend to run an hour before sleep rather than all evening, so a bedroom machine often uses half what a living-room one does. A room used at weekends only uses a seventh. Set against that, hot dry weather and heavy air conditioning make people fill more often, and an open window or a ceiling fan empties a room faster than any dose can fill it, which quietly increases consumption without improving anything. If your figure lands between two bottle sizes, take the smaller one — you will change fragrance before you regret it.
Then buy in a sequence that protects the decision. Test at 15ml or with the three bottles that came with your Sukoon, live with a scent for a month in the room it is meant for, and only then buy the size your arithmetic pointed at. If you are running two fragrances, a 300ml of the main one and a 100ml of the second is the combination that fits almost every multi-room house — ₹2,798 and well over a year of both. Rinse the tank when you change scents, use filtered water in hard-water cities, keep the bottles out of direct sunlight and away from children and pets, and never put raw essential or carrier oils into an ultrasonic machine.
The right bottle for your machine count
Consumption at four drops a tank and one fill a day per machine, the bottle that matches it, and what a year of fragrance costs at that size. Every figure here is smaller than people expect.
| Your setup | Millilitres a year | The right bottle | Fragrance cost a year |
|---|---|---|---|
| One machine | 72ml | 100ml ₹999 — about 16 months | ≈ ₹719 |
| Two machines | 144ml | 300ml ₹1,799 — about 25 months | ≈ ₹864 |
| Three machines ★ | 216ml | 300ml ₹1,799 — about 17 months | ≈ ₹1,296 |
| Four machines | 288ml | 300ml ₹1,799 — about 12 months | ≈ ₹1,728 |
| Five machines | 360ml | 300ml + a 100ml = ₹2,798 | ≈ ₹2,160 |
| Three machines, run hard | 648ml | Two × 300ml = ₹3,598 a year | ≈ ₹3,888 |
Versailles
The advice I give most often on bottle size is the one that sells the smaller bottle. If you have one machine, buy the 100ml. The 300ml is four years of your life at that rate, and I have never met anybody who wanted the same fragrance in the same room for four years. You will move the machine, or the season will change, or you will smell something at a friend's house and want it.
The 300ml is a genuinely excellent buy at three or four machines, and that is not a different opinion — it is the same rule applied to a different home. Four machines get through roughly 288 millilitres a year. A 300ml bottle is therefore almost exactly one year of a fully scented house, at the best rate in the range, and every room running the same liquid. That is what it was priced for.
What I would never do is buy the large bottle before testing. A 15ml costs ₹299 and gives you two months of honest trial in the actual room; the three that come with a Sukoon give you six. Use them, decide slowly, then buy once and forget about it for a year. A portion of every order supports girl-child education through Nanhi Kali, whichever size you end up with.
Frequently asked questions
- How much do diffuser refills actually cost per month? — the millilitre arithmetic in full.
- Is the Pack of 7 worth it for a multi-room home? — what ₹1,799 of testing buys.
- What does it cost to scent your whole home? — hardware once, fragrance monthly.
- The complete SOSA home scenting buying guide — every home type, every budget.
- Brand: the SOSA founder story.
SOSA products & prices (verified August 2026): Hotel Collection water-based ultrasonic diffuser fragrance 15ml ₹299 · 100ml ₹999 · 300ml ₹1,799 · Pack of 7 (15ml, all fragrances) ₹1,799; refills 100ml from ₹999. Seven scents: The Ritz-Carlton-inspired (white tea · bergamot · cedar), Westin-inspired (white tea · aloe · cedar), 1 Hotels-inspired (cedarwood · vetiver · green leaves), The St. Regis-inspired (amber · violet · woods), Shangri-La-inspired (jasmine · green tea · white tea), Four Seasons-inspired (citrus · floral · sandalwood), W Hotels-inspired (citrus · pepper · amber). Diffusers: Boond 300ml ₹899 · Sukoon 500ml ₹1,899 · Megh 6L ₹3,499. Water-based, phthalate-free, composed to IFRA standards for home diffusion; 3–6 drops per tank. Made in India, Pune. The Hotel Collection scents are SOSA's own interpretations inspired by the world's finest hotels; all hotel names are trademarks of their respective owners and are used only to describe the scent style — SOSA is an independent Indian fragrance house, not affiliated with or endorsed by any hotel brand. Prices and availability subject to change — see the live product pages.