Raw Honey Guide

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Reference table · UMFHA tier ladder · 26 rows

UMF vs MGO: the decoder

The UMF Honey Association publishes a 26-row tier ladder mapping every UMF rating to a minimum methylglyoxal concentration in mg/kg. Unlike traditional varieties like wildflower honey, clover honey, or buckwheat honey which rely on peroxide-based activity, Manuka's distinctive lab antibacterial activity comes from non-peroxide methylglyoxal. Here it is in one place, decoded for buyers, with an interactive converter, the band each tier sits in (entry / low / mid / high / very high / ultra-rare), and a clear explanation of why KFactor is not on this ladder at all.

The relationship is published, non-linear, and unambiguous: UMF 5+ floors at MGO 83, UMF 10+ at MGO 263, UMF 15+ at MGO 514, UMF 20+ at MGO 829, UMF 25+ at MGO 1200. Everything in between sits on a curve, not a straight line.

Last updated · companion blog at /blog/manuka-honey-grading-systems-explained

Looking for cost rather than grade meaning? Compare the dated Mānuka price model by MGO and UMF.

UMF 5+ floor
MGO 83
entry / authenticity
Common reference grade
UMF 10+
MGO 263 mg/kg
UMF 25+ floor
MGO 1200
≈14× the entry band
UMF→MGO multiplier
non-linear
use the published ladder

Interactive converter

Move the slider to the UMF rating on a jar. The MGO floor, band, and buyer-level meaning come straight from the published ladder.

UMF rating
UMF 10+
MGO floor
263
mg/kg methylglyoxal
Band
Mid

A common retail reference grade. No health benefit has been shown to start at this level.

Three systems, three different things

Buyer confusion almost always traces to one of these three labels being treated as if it were the same as another. They are not. Each measures a different thing, on a different scale, certified by a different body.

UMF

Unique Manuka Factor

Custodian: UMF Honey Association (New Zealand)

Measures: A four-marker authenticity profile: methylglyoxal (MGO), leptosperin (botanical fingerprint unique to Leptospermum nectar), DHA (the precursor to MGO), and HMF (a freshness/heat-damage indicator).

Scale: The number comes from a lab phenol-equivalence test: UMF 10+ means non-peroxide antibacterial activity on a test plate equivalent to a 10% phenol solution. Today each tier also has an MGO floor.

Strength: The only system that bundles authenticity (leptosperin), potency (MGO), maturity (DHA), and freshness (HMF) into one number.

Weakness: Licensing fee is significant; some genuine producers opt out and report MGO directly.

MGO

Methylglyoxal in mg/kg

Custodian: No central body — direct chemical assay

Measures: A direct lab measurement of methylglyoxal concentration in the honey, expressed in milligrams per kilogram. MGO is the compound responsible for Manuka's non-peroxide antibacterial activity.

Scale: Linear chemical concentration. Higher MGO = more methylglyoxal, period. No phenol-equivalence translation involved.

Strength: Unambiguous. Any accredited lab can verify any MGO claim. Adams et al. 2008 and Mavric et al. 2008 identified MGO as the source of NZ Manuka's non-peroxide antibacterial activity in lab tests.

Weakness: MGO alone does not authenticate the honey as Leptospermum-derived — leptosperin or pollen analysis is needed for that.

KFactor

Wedderspoon proprietary index

Custodian: Wedderspoon Organic Inc.

Measures: A pollen-count and total-activity index, not a methylglyoxal measurement. KFactor 12 / 16 / 22 indicate the percentage of Manuka pollen in the jar plus general antibacterial activity.

Scale: Proprietary scale — does not map to UMF or MGO ladders and is not licensable across producers.

Strength: Reports Manuka pollen content, which says something about the honey's botanical source.

Weakness: Pollen count is a botanical-presence test, not an antibacterial-activity test. A jar can satisfy a pollen threshold without a stated MGO level. A 2015 U.S. class-action complaint alleged the brand's 12+ and 16+ ratings implied UMF-equivalent strength; it was voluntarily dismissed later that year.

The full UMFHA tier ladder

Every tier in the published UMFHA ladder, with the methylglyoxal floor in mg/kg and the buyer-level meaning of each band. Bands shade from entry (light) to ultra-rare (deep).

UMFMGO floor (mg/kg)BandWhat this rating means for buyers
UMF 5+83EntryLowest licensed UMF tier: the Manuka markers are present at the minimum level.
UMF 6+117EntryOne step above the floor.
UMF 7+159LowLow MGO band.
UMF 8+200LowLow MGO band.
UMF 9+240LowLow MGO band; last tier below UMF 10+.
UMF 10+263MidA common retail reference grade. No health benefit has been shown to start at this level.
UMF 11+311MidOne step above 10+.
UMF 12+356MidMid MGO band.
UMF 13+405MidMid MGO band.
UMF 14+458MidMid MGO band; MGO floor about 5.5× the UMF 5+ floor.
UMF 15+514HighHigh MGO band; a common premium retail grade.
UMF 16+572HighHigh MGO band.
UMF 17+633HighHigh MGO band.
UMF 18+696HighHigh MGO band.
UMF 19+761HighHigh MGO band. The highest of six NZ Manuka honeys Mavric et al. measured in 2008 was 761 mg/kg.
UMF 20+829Very highVery high MGO band; less common on shelves.
UMF 21+899Very highVery high MGO band.
UMF 22+971Very highVery high MGO band; MGO floor about 12× the UMF 5+ floor.
UMF 23+1046Very highVery high MGO band.
UMF 24+1122Very highVery high MGO band.
UMF 25+1200Ultra-rareRare; MGO 1,200+.
UMF 26+1281Ultra-rareRare.
UMF 27+1365Ultra-rareRare.
UMF 28+1450Ultra-rareRare.
UMF 29+1538Ultra-rareRare.
UMF 30+1628Ultra-rareTop of the published ladder. Rare.

Source: UMF Honey Association published tier ladder (umf.org.nz). Methylglyoxal identified as the non-peroxide antibacterial compound by Adams et al. 2008 (Carbohydrate Research) and Mavric et al. 2008 (Mol. Nutr. Food Res., 38–761 mg/kg in six NZ Manuka honeys); MGO–activity correlation from Atrott & Henle 2009 (Czech J. Food Sci.). Higher MGO values exist but are rarer. All are lab measurements, not health outcomes.

Why KFactor is not on this ladder

KFactor is a Wedderspoon-proprietary index. The number primarily reports the percentage of Manuka pollen present in the jar, plus a general antibacterial test reported as Total Activity (TA). Both UMF and MGO ratings, in contrast, report the non-peroxide antibacterial activity that comes specifically from methylglyoxal — the bioactive Manuka chemistry.

Pollen presence is a good botanical-source signal: bees foraged on Manuka flowers. But pollen presence is not an antibacterial-activity measurement. A jar can satisfy a KFactor pollen threshold without a stated MGO level.

A 2015 U.S. class-action complaint alleged that Wedderspoon's 12+ and 16+ ratings implied UMF-equivalent antibacterial strength; it was voluntarily dismissed later that year. Product labeled KFactor 16 — without a co-stated MGO value — cannot be placed on the published UMFHA tier ladder. Cross-checking the jar for an explicit MGO mg/kg figure is the simplest way to compare against UMF.

How to read a Manuka jar in under 30 seconds

  1. Look for UMF or MGO first. Either is a measurable, verifiable rating. KFactor alone is not.
  2. Cross-check on the ladder above. If the jar shows MGO 514 but no UMF, the equivalent UMF tier is 15+. If it shows UMF 10+ but no MGO, the equivalent MGO floor is 263.
  3. Decide how much you want to pay. No study shows a particular UMF or MGO grade gives a health benefit when eaten, so a higher grade buys more methylglyoxal, not a proven effect. For everyday eating, wildflower honey, clover honey or buckwheat honey cost far less. Medical-grade wound dressings are sterilized products used by clinicians, not retail jars.
  4. Check NZ origin if it matters to you. Australian Leptospermum honey can carry MGO ratings but is a different category. Most UMF-licensed jars are NZ-origin per the UMFHA license terms.
  5. If KFactor is the only marker, ask for an MGO test report. Genuine producers can supply an independent MGO assay on request.

Frequently asked questions

What is the simplest way to convert UMF to MGO?
Use the official UMFHA-published tier ladder. UMF 5+ = MGO 83+, UMF 10+ = MGO 263+, UMF 15+ = MGO 514+, UMF 20+ = MGO 829+, UMF 25+ = MGO 1200+. The relationship is non-linear; do not interpolate by simple multiplication. Whenever a jar shows one rating but not the other, the published ladder is the best reference.
Why is the UMF→MGO relationship non-linear?
UMF was designed in the 1990s as an equivalence rating against phenol disinfectant (a 10% phenol solution killed bacteria as effectively as a UMF 10+ honey). Methylglyoxal — identified as the active compound in 2008 by Adams and colleagues and by Mavric and colleagues — accumulates in honey via dihydroxyacetone (DHA) conversion, which is a kinetic process. The chemistry of phenol equivalence and MGO accumulation do not produce a straight line. They produce the curved ladder UMFHA publishes.
Is UMF 10+ the actual therapeutic threshold?
No. UMF 10+ / MGO 263+ is a marketing convention, not a clinical threshold. No study has shown that eating Manuka honey at UMF 10+, or at any grade, treats or prevents illness. Wound care uses sterilized medical-grade honey dressings applied by clinicians, not retail jars. Lower tiers still confirm the honey is Manuka. In lab tests, Manuka keeps antibacterial activity when its hydrogen peroxide is removed; ordinary honeys like wildflower honey, clover honey and buckwheat honey do not.
Why is KFactor not the same as UMF or MGO?
KFactor is a Wedderspoon-proprietary index that primarily reports the percentage of Manuka pollen in the jar, plus a general "Total Activity" antibacterial test. Pollen presence is a botanical-source signal (the bees foraged on Manuka), but it is not a methylglyoxal measurement. KFactor 16 does not equal UMF 16+. A 2015 U.S. class-action complaint alleged that Wedderspoon's 12+ and 16+ ratings implied UMF-equivalent antibacterial strength; it was voluntarily dismissed later that year. Honey labeled KFactor without a co-stated MGO value cannot be placed on the UMFHA ladder.
Does a higher UMF jar work proportionally better for sore throat?
No study shows that. No trial has compared Manuka grades for sore throat, and no trial shows Manuka works better than wildflower honey or clover honey for a sore throat or cough. For honey in general, a 2021 BMJ Evidence-Based Medicine review of 14 studies found it improved cough frequency and severity in upper respiratory infections compared with usual care. A higher grade buys more methylglyoxal at a much higher price, not a proven benefit. See a doctor for a sore throat that is severe or lasts more than a few days.
Why do some authentic Manuka producers report only MGO without UMF?
UMF licensing carries an annual cost and a four-marker testing protocol. Some producers prefer to publish a direct MGO number (which any accredited food lab can verify) and skip the UMF licensing fee. Their honey can be entirely genuine — the MGO assay alone is unambiguous. The trade-off is that without a UMF mark, leptosperin (botanical authenticity) is not certified by an external body. Cross-checking a producer's independent test report is the practical solution.
How does Manuka's antibacterial activity compare to ordinary raw honey?
Most raw honey varieties including wildflower honey, clover honey, and buckwheat honey have antibacterial activity from glucose oxidase producing low levels of hydrogen peroxide (H₂O₂) on dilution with wound exudate. In lab tests that peroxide activity is destroyed by catalase. Manuka's methylglyoxal activity is non-peroxide, so it persists when catalase is added. In a 2009 study of 61 Manuka honeys (Atrott & Henle), antibacterial activity rose in step with MGO content. These are lab measurements; they do not show that eating Manuka has a health effect that wildflower, clover or buckwheat honey lack.
Where do these MGO numbers come from for the ladder?
The UMF Honey Association publishes the complete tier ladder on its website (umf.org.nz). The numbers used here are those published thresholds. The chemistry behind the ladder traces to Adams et al. 2008 (Carbohydrate Research, identification of MGO as the non-peroxide active compound), Atrott & Henle 2009 (Czech J. Food Sci., MGO–antibacterial activity correlation in 61 honeys), and Mavric et al. 2008 (Mol. Nutr. Food Res., MGO 38–761 mg/kg in six NZ Manuka honeys).
What is leptosperin and why does UMF require it?
Leptosperin is a glycoside that occurs naturally and almost exclusively in nectar from Leptospermum (Manuka) flowers. Detecting leptosperin in a jar of honey is strong evidence the honey is genuinely Leptospermum-derived rather than a non-Manuka honey spiked with synthetic MGO. The UMF four-marker profile requires a minimum leptosperin reading at every tier — that is the authenticity check that pure MGO assays cannot provide on their own.
Should I pay for UMF 25+ rather than UMF 15+?
For most buyers, no. Above UMF 15+ the price climbs steeply, and no study shows a higher grade gives a health benefit when eaten. A high grade makes sense mainly if you want the label itself, for example as a gift. Wound care uses sterilized medical-grade honey products, not retail jars. For everyday eating, a lower grade or another honey costs far less.
How does Manuka honey compare to other premium varieties like buckwheat or wildflower?
Manuka is graded by its methylglyoxal content; other honeys are not. Buckwheat honey is dark and malty, clover honey is mild, wildflower honey varies with the flowers in bloom, and acacia honey stays liquid for a long time and tastes mild. For everyday eating, wildflower or buckwheat honey cost far less than Manuka, and no study shows Manuka is healthier to eat.

Related pages

UMF vs MGO vs KFactor — Long formManuka Honey BenefitsBest Honey BrandsWorld Honey ReferenceResearch MethodologyCertification AuditManuka Variety ProfileManuka vs Clover Comparison