How extensive is my melasma today?
Grade each of the four weighted face regions for area of involvement and pigment darkness — plus homogeneity in classic MASI — and the tool computes the Melasma Area and Severity Index: 0–48 classic, 0–24 modified. Save a score each visit and it tracks your change over time, with the MASI 50 / 75 / 90 response yardsticks used in melasma trials. Everything stays on this device.
Forehead
0.3× A 0× D 0 + H 0= 0.0 Right malar
0.3× A 0× D 0 + H 0= 0.0 Left malar
0.3× A 0× D 0 + H 0= 0.0 Chin
0.1× A 0× D 0 + H 0= 0.0 There are no published severity bands for either score — interpret the raw value, its position on the scale, and its change between visits. In melasma trials, a drop of at least 50%, 75%, or 90% from baseline (MASI 50 / 75 / 90) is the usual yardstick of treatment response; saved scores below are compared the same way.
A scoring aid for self-education, not a diagnosis — MASI and mMASI are clinician-oriented severity instruments, and treatment decisions shouldn’t rest on this number alone. Bring it to your GP or dermatologist instead.
Changes are only compared between scores of the same variant — MASI (0–48) and mMASI (0–24) totals are not interchangeable.
Grading reference — what each grade means
Area of involvement (A)
How much of this region’s skin shows melasma? Estimate the percentage of the region’s surface that is pigmented — the tool converts it to the 0–6 grade, or tap a grade directly.
Proportion of the region’s surface affected by melasma, graded 0–6. Assess each region independently — the percentage refers to that region only, not the whole face.
Darkness (D)
How dark is the pigment compared with the surrounding normal skin? Barely perceptible = 1; very dark, dense pigment = 4.
Intensity of the hyperpigmentation relative to uninvolved skin, graded 0–4. Counted in both MASI and mMASI.
Homogeneity (H)
How uniform is the pigment across the involved area? Even, confluent colour = low grade; blotchy, speckled or reticulated patches = high grade. Counted in classic MASI only.
Uniformity of the pigment within the involved area, graded 0–4. Excluded from the modified mMASI (Pandya 2011), which found it the least reliable component.
Source: Kimbrough-Green CK, Griffiths CEM, Finkel LJ, et al. Topical retinoic acid (tretinoin) for melasma in black patients. Arch Dermatol. 1994;130(6):727–733 (MASI). Pandya AG, Hynan LS, Bhore R, et al. Reliability assessment and validation of the Melasma Area and Severity Index (MASI) and a new modified MASI scoring method. J Am Acad Dermatol. 2011;64(1):78–83 (mMASI). MASI/mMASI define only the raw score; no severity bands are published.
Pigment shifts slowly, and lighting lies — melasma can look dramatically different between window light and bathroom bulbs before anything real has changed. Score yourself in the same spot and the same light each time, and pair the number with photos from the Photo Tracker taken under identical conditions. Because UV and even visible light keep driving the pigment, daily protection is the floor of any plan — the Sun Safety planner covers it. And when consistent topicals and sunscreen aren’t moving the score, the melasma therapy guide walks through what dermatologists escalate to next, in order.
Saved only on this device — and browsers erase site data. A history clear, a private window, or Safari's automatic deletion after seven days without a visit will take this log with it. The fix is a free DermApproved account: it backs this up automatically and puts it on every device you sign in to — details in how storage works.
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How the MASI calculator works
The Melasma Area and Severity Index divides the face into four regions weighted by their share of the facial surface — forehead 30%, right malar (cheek) 30%, left malar 30%, and chin 10%. In each region you grade the area involved from 0 to 6 (converted from the percentage of that region’s surface showing pigment), the darkness of the pigment from 0 to 4, and — in the classic score — its homogeneity, meaning how uniform versus blotchy the pigment is, also 0 to 4. Each region contributes weight × Area × (Darkness + Homogeneity), and the four subtotals sum to a classic MASI of 0–48 (Kimbrough-Green et al., Archives of Dermatology, 1994). The modified mMASI (Pandya et al., Journal of the American Academy of Dermatology, 2011) dropped homogeneity after reliability testing showed it was the hardest component to grade consistently without adding accuracy, so each region becomes weight × Area × Darkness and the total runs 0–24.
Unusually for a dermatology score, neither version publishes severity bands — there is no official cutoff for “mild” or “severe” melasma. The score is built for tracking: melasma trials report treatment response as MASI 50, 75, or 90, meaning at least a 50%, 75%, or 90% reduction from baseline, and this tool applies the same yardsticks between your saved scores (comparing only like-with-like, since the two variants’ totals aren’t interchangeable). Saved scores stay on this device, one per day, each tagged with the variant that produced it. For the fuller melasma picture, pair the score with the melasma therapy guide, consistent-light photos from the Photo Tracker, and the Sun Safety planner — UV exposure is what keeps the pigment fed.
Common questions
Is this the same MASI score a dermatologist would calculate?
Same instrument, same arithmetic. Clinicians grade the identical four weighted regions — forehead, both malar cheeks, and chin — for area, darkness, and (classic MASI) homogeneity, then sum weight × area × intensity exactly as this tool does. The difference is the grading eye: a trained assessor is more consistent, which is why your own scores are most useful compared against each other, graded in the same mirror and the same light every time.
Should I use classic MASI or the modified mMASI?
For routine self-tracking, mMASI — the 2011 modification dropped homogeneity after reliability testing showed it was the hardest component to grade consistently without improving accuracy, and most modern melasma studies report mMASI. Classic MASI matters when you need comparability with older literature on the 0–48 scale. The two totals are not interchangeable, so pick one method and keep it for every score you intend to compare — the tool tracks the variant on each saved entry for exactly this reason.
What score counts as severe melasma?
Neither MASI nor mMASI publishes severity bands, so no number officially means “mild” or “severe” — the instruments define only the raw score. What the score is built for is change: melasma trials call a drop of at least 50% from baseline a MASI 50 response, with 75% and 90% as the stronger yardsticks. A trend across saved scores tells you far more than any single reading.
Why does my melasma look so different from day to day?
Lighting, mostly — melasma is notoriously light-dependent, and the same patches can look faint by a window and dramatic under bathroom bulbs, before any real pigment change has happened. Grade yourself in the same spot, in the same light, at the same time of day, and pair scores with photos from the Photo Tracker taken under identical conditions. Genuine change is also slow: UV and even visible light keep stimulating the pigment, which is why daily sunscreen is the floor of every melasma plan.
Where do my saved scores go?
Into your own browser’s local storage on this device — nothing is uploaded to DermApproved or anywhere else. The trade-off is fragility: clearing browser data erases the history, and it won’t follow you to another device, so download a backup from My Library once you have a run of scores worth keeping. Each entry records the date, the score, and which variant produced it.