Household cleaning
Fairy Original Washing Up Liquid dupe
Why pay around £1.25 for Fairy? The bulk active is SLES 70% paste (sodium laureth sulphate) — 92% less per working litre than a typical shelf pack.
From the retail pack to the active and the mix
1 · Retail
Fairy Original Washing Up Liquid
320 ml bottle · £1.25 typical snapshot
Water, cocamidopropyl betaine, perfume and colour
2 · Active
Sodium laureth sulphate (SLES)
15% on the label
68585-34-2C12H25(OCH2CH2)nOSO3Na
Bulk SLES 70% paste (sodium laureth sulphate)
3 · Mix
1 part 70% paste + 34 parts water ≈ 2% working (Fairy band)
£0.03 per working litre · 92% less than the shelf pack
- Active
- Sodium laureth sulphate (SLES)
- CAS
- 68585-34-2
- Dupe
- SLES 70% paste (sodium laureth sulphate)
- Saving
- 92% / L
Saving is per litre of working-strength mix versus a typical pack price, not versus the DIY kit total. Shop prices move — always check the listing.
Label teardown
What the pack promises versus what the label chemistry actually is.
The marketing claim
“Cuts through grease fast”
The chemical reality
Fairy is mostly water and SLES — the workhorse anionic surfactant in almost every UK washing-up bottle. A 25 kg drum of SLES 70% paste dilutes to hundreds of litres of 2% working liquor. You are paying for the green bottle and the scent, not a proprietary molecule.
Active vs filler
15% Sodium laureth sulphate (SLES) · 85% carrier / filler — Water, cocamidopropyl betaine, perfume and colour
- Typical retail
- £1.25
- 320 ml bottle
- Estimated active cost
- £0.06
- Scaled from bulk £22.00 / 25 kg
- Indicative markup
- 20.7×
- Snapshot maths, not a live shop price
The Marketing Claim & The Catch
A 320 ml bottle pack of Fairy Original Washing Up Liquid typically retails around £1.25 in household cleaning. That is a UK shelf-price snapshot for the maths on this page — not a live shop quote or a manufacturer RRP. Listings, sizes and deals move. The marketing line is that you are buying a finished lifestyle product, not a weighed chemical.
On the pack: Cuts through grease fast; Lasts longer than value brands; and Gentle on hands.
The catch: Fairy is mostly water and SLES — the workhorse anionic surfactant in almost every UK washing-up bottle. A 25 kg drum of SLES 70% paste dilutes to hundreds of litres of 2% working liquor. You are paying for the green bottle and the scent, not a proprietary molecule.
- “Cuts through grease fast”
- “Lasts longer than value brands”
- “Gentle on hands”
Proprietary Blend & Dosage Breakdown
The labelled active is Sodium laureth sulphate (SLES) at 15%. Everything else in the pack is water, cocamidopropyl betaine, perfume and colour.
At 15% active, most of what you pay for is carrier and packaging. The brand is selling convenience, fragrance and a label — not a uniquely potent molecule.
Branded working strength is whatever comes out of the bottle. The bulk alternative is 70% SLES 70% paste (sodium laureth sulphate), mixed to 1 part 70% paste + 34 parts water ≈ 2% working (Fairy band).
- Labelled active
- Sodium laureth sulphate (SLES)
- 15%
- Carrier
- Water, cocamidopropyl betaine, perfume and colour
- Retail pack
- 320 ml bottle · £1.25
The Active Chemical Alternative (Dupe Stack)
The dupe stack is SLES 70% paste (sodium laureth sulphate) at 70% bulk. Indexed as CAS 68585-34-2, formula C12H25(OCH2CH2)nOSO3Na. Buy it as 25 kg for around £22.00 from Amazon UK.
Working strength: 1 part 70% paste + 34 parts water ≈ 2% working (Fairy band). Indicative cost £0.03 per diluted litre — 92% below a typical branded pack on a per-litre basis, before you reuse leftover bulk.
Follow the mixing method and the supplier SDS. Wear the listed PPE. Do not mix incompatible oxidisers, acids or ammonia.
- Irritant to eyes. Gloves if you have eczema. Work in a ventilated kitchen.
- To approach branded ~15% strength: dissolve 285 g of 70% SLES paste in 1 litre of warm water (≈20% concentrate). For general washing-up, dilute further to ~2% (20 ml concentrate per litre).
- Optional: a few drops of essential oil for scent. Do not mix with bleach, quat biocides or strong acids.
- 25 kg of paste makes well over 100 litres of 2% working liquor — years of dishes versus a 320 ml bottle.
Dilution recipe
1 L working batch
Working strength 1 part 70% paste + 34 parts water ≈ 2% working (Fairy band). Educational estimate from the listed ratio — check the SDS before you mix.
Chemical
29 millilitres
SLES 70% paste (sodium laureth sulphate)
Water
0.97 litres
Carrier / diluent
3% concentrate · 97% water by working volume (solids are dissolved into the water share).
Required PPE
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Side-by-Side Price & Potency Comparison
Head-to-head comparison
| Measure | Retail brandedFairy | Raw active dupeDupeStack |
|---|---|---|
| Product | Original Washing Up LiquidAmazon UK search — listing, not a confirmed seller | SLES 70% paste (sodium laureth sulphate) |
| Pack / unit | 320 ml bottle · £1.25 | 25 kg · £22.00 |
| Active | Sodium laureth sulphate (SLES) at 15%Carrier: Water, cocamidopropyl betaine, perfume and colour | 70% bulkC12H25(OCH2CH2)nOSO3Na |
| CAS number | Not disclosed on pack | 68585-34-2 |
| Working strength | Ready-to-use pack | Dilute 1 part 70% paste + 34 parts water ≈ 2% working (Fairy band) |
| Cost per litre | £3.91 / L typical pack | £0.03 / L mixed from bulk |
| Headline saving | Baseline | 92% cheaper |
| COSHH / PPE | Follow the branded SDS | Gloves. Chemical-resistant gloves (nitrile or neoprene) |
Active ingredient and cheaper alternative — FAQ
Can I use Fairy to boost patio biocide?
No. Anionic SLES can neutralise cationic quats (BAC/DDAC) and wreck the biocide. Never mix washing-up liquid with Patio Magic, Wet & Forget or Jeyes 4-in-1.
Is SLES the same as soap?
No. SLES is a synthetic sulphate surfactant (CAS 68585-34-2). Traditional soap is fatty-acid salt chemistry. Both cut grease; they behave differently in hard water and in mixes with other cleaners.
How do you mix the Original Washing Up Liquid dupe stack?
Irritant to eyes. Gloves if you have eczema. Work in a ventilated kitchen. To approach branded ~15% strength: dissolve 285 g of 70% SLES paste in 1 litre of warm water (≈20% concentrate). For general washing-up, dilute further to ~2% (20 ml concentrate per litre). Optional: a few drops of essential oil for scent. Do not mix with bleach, quat biocides or strong acids. 25 kg of paste makes well over 100 litres of 2% working liquor — years of dishes versus a 320 ml bottle.
DupeStack provides chemical concentration data and educational mixing guides only. Wellness pages compare food supplements, not medicines or prescribed treatments. Always review the supplier Safety Data Sheet (SDS) and comply with UK Health and Safety Executive (HSE) and COSHH regulations when handling concentrated substances. Mixing and storage are at your own risk. Some links are affiliate advertisements (Amazon Associates, eBay Partner Network, and Awin when those programmes are live). Commissions do not change listed concentrations or calculator output.
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£28.00Save 92% / L
Indicative DIY stack