If you’ve shopped for manuka honey, you’ve met the numbers: UMF 10+, UMF 15+, UMF 16+, UMF 20+, sometimes a rare and eye-watering UMF 30+. Sitting beside them, often on the same label, is a second set — MGO 263, MGO 514, MGO 829. It looks like a code, and most shoppers either ignore it or assume bigger is simply better. Neither is quite right.
Those numbers are the single most important thing on the jar. They’re the reason manuka is worth its price — or the reason a particular jar isn’t. This guide explains what UMF actually measures, how it relates to MGO, and which grade to reach for depending on what you’re using it for. If you want the why first — what manuka honey is genuinely good for — start with The Benefits of Manuka Honey, then come back here to buy the right one.
What UMF actually means
UMF stands for Unique Manuka Factor. It’s a certification and grading system run by the UMF Honey Association in New Zealand, and it exists because “manuka” on a label, by itself, guarantees very little. A jar can say manuka and be weak, watered down with cheaper honey, or not really manuka at all. UMF is the quality-control stamp that pushes back on that.
What makes UMF more than a marketing badge is that it doesn’t measure just one thing. To carry a UMF number, a honey is tested for four separate markers:
- MGO (methylglyoxal) — the potency marker. This is the stable, non-peroxide antibacterial compound that makes manuka special. The higher the MGO, the stronger the antibacterial activity, and it’s the main driver of the UMF number.
- Leptosperin — the authenticity marker. Leptosperin occurs naturally in genuine manuka nectar and is very hard to fake, so its presence proves the honey really is manuka.
- DHA (dihydroxyacetone) — the precursor that slowly converts into MGO as the honey matures. It signals the honey’s freshness and its future potency.
- HMF — a freshness marker that shows the honey hasn’t been overheated or stored too long.
So a real UMF number is telling you four things at once: this is potent, it’s authentic, it’s fresh, and it will hold its strength. That’s why a licensed UMF rating carries more weight than a bare “manuka” claim or an MGO number standing alone.
UMF vs MGO: two systems, one honey
This is the part that confuses everyone, so here it is plainly. UMF and MGO are two different rating systems measuring related things.
- MGO is a direct measurement of methylglyoxal, in milligrams per kilogram. It’s a single-compound potency number.
- UMF is a broader grade that includes that potency plus the authenticity and freshness checks above.
Because MGO is the biggest ingredient in the UMF score, the two track together closely, and the industry uses an approximate conversion so you can compare jars. Strictly speaking the UMF Association notes that MGO doesn’t “officially” convert to UMF — they’re distinct systems — but the practical mapping below is accurate enough for shopping and is what most reputable sellers use.
The UMF-to-MGO conversion table
| UMF grade | Approx. MGO (mg/kg) | What it’s for |
|---|---|---|
| UMF 5+ | ~83 | Entry level — a nice honey, minimal therapeutic edge |
| UMF 8+ | ~200 | Light daily use |
| UMF 10+ | ~263 | The usual therapeutic starting point — everyday wellness, throats, digestion |
| UMF 12+ | ~356 | Slightly stronger everyday grade |
| UMF 15+ | ~514 | Premium sweet spot — strong support without clinical pricing |
| UMF 16+ | ~572 | Premium — a common step up from 15+ |
| UMF 18+ | ~696 | Premium, higher potency |
| UMF 20+ | ~829 | Clinical grade — targeted and wound-care contexts |
| UMF 22+ | ~971 | Clinical, high strength |
| UMF 24+ | ~1122 | Clinical, very high strength |
| UMF 26+ | ~1281 | Ultra-rare |
| UMF 28+ | ~1450 | Ultra-rare |
| UMF 30+ | ~1620 | Ultra-rare, maximum potency — scarce and expensive |
The pattern to notice: the MGO numbers climb steeply. Going from UMF 15+ to UMF 30+ roughly triples the methylglyoxal — and often more than triples the price — for a benefit most everyday uses will never notice.
Which UMF number should you actually buy?
More is not automatically better; appropriate is better. Here’s the honest breakdown.
For everyday wellness, sore throats, and digestive comfort — UMF 10+ to 15+. This is where most people should live. UMF 10+ (around MGO 263) is the widely accepted therapeutic starting line: strong enough to matter, gentle on the budget. UMF 15+ is the practical sweet spot if you want a clear step up. This is the grade to stir into warm water for a scratchy throat or to upgrade the raw honey in the Honey-Garlic Throat Tonic when a bacterial throat infection is brewing.
For premium daily support or when you want extra strength — UMF 16+ to 18+. A reasonable choice if you use manuka often and want more antibacterial activity per spoonful. Diminishing returns start creeping in here, but many people happily buy in this band.
For targeted, higher-strength or topical/wound-adjacent use — UMF 20+ and above. UMF 20+ (around MGO 829) is the “clinical grade” threshold. This is the range to consider for more serious antibacterial intent — though genuine wound care should follow medical guidance, and for a wound that won’t heal the grade of your honey is not the first question to ask.
UMF 24+ to 30+ — collectors’ territory. These are rare, dramatically more expensive, and for most households represent money spent on a bigger number rather than a meaningfully better outcome. Real, occasionally worth it for specific targeted use — but not the everyday jar.
If you want one recommendation to keep it simple: UMF 10+ or 15+ is the right jar for almost everyone. Reach higher only when you have a specific reason.
How to make sure the number is real
The grade only protects you if it’s genuine, so:
- Look for the UMF trademark and a licence number on the label — a real UMF product is traceable to a licensed producer.
- Expect it to say New Zealand (with some genuine manuka from Australia).
- Be suspicious of a jar that shouts “manuka” but carries no UMF or MGO number at all — that’s the tell for weak or blended honey.
- Treat a very high grade at a suspiciously low price as a red flag; genuine high-UMF honey is scarce and priced accordingly.
The short version
UMF is a four-part quality grade — potency, authenticity, freshness, and staying power — anchored by the MGO measurement of manuka’s key antibacterial compound. The numbers map to MGO on a steeply rising curve, which means the jump from a mid grade to a top grade costs far more than the extra benefit is worth for ordinary use. For the vast majority of people and purposes, UMF 10+ to 15+ is the smart buy. Match the grade to the job, check that the number is licensed and real, and you’ll get every one of the benefits of manuka honey without overpaying for a number you’ll never feel.