Laser hair removal works by targeting melanin in the hair follicle with a specific wavelength of light. The number of sessions required depends on the contrast between skin and hair colour (Fitzpatrick type), the treatment area's hormonal sensitivity, and whether hormonal conditions like PCOS are present.
This calculator uses the Fitzpatrick scale (1975), hair melanin data, and area-specific hormonal modifiers to estimate your session count, recommended laser wavelength, and pigmentation risk level.
Laser Hair Removal Calculator
Laser Hair Removal Session Estimator
Uses the Fitzpatrick skin type scale (Fitzpatrick 1975), hair melanin data, and area-specific hormonal modifiers.
Type II — Fair, burns easily, tans minimally
Excellent
Non-hormonal, responds predictably
Fitzpatrick scale reference
| Type | Skin tone | Risk | Recommended laser |
|---|---|---|---|
| I | Very fair, always burns, never tans | Low | Alexandrite / IPL / Diode |
| II | Fair, burns easily, tans minimally | Low | Alexandrite / IPL / Diode |
| III | Medium, sometimes burns, tans gradually | Low–Mod | Diode / Nd:YAG |
| IV | Olive/brown, rarely burns, tans easily | Mod | Nd:YAG / Diode |
| V | Dark brown, rarely burns | Mod–High | Nd:YAG 1064nm only |
| VI | Very dark, never burns | High | Nd:YAG 1064nm (specialist) |
Estimated treatment plan
Estimated sessions
4–6 sessions
6–8 wks intervals · Legs · Type II skin
Recommended laser technology
Alexandrite / IPL / Diode
Pigmentation risk
LowTypical reduction per session
Fitzpatrick skin type and laser selection
Fitzpatrick I–II (very fair to fair skin with dark hair) has the highest melanin contrast and responds best to Alexandrite, IPL, or Diode lasers. 4–6 sessions at 6–8 week intervals are typical, with low pigmentation risk.
Fitzpatrick III–IV (medium to olive skin) requires Diode or Nd:YAG lasers. 6–10 sessions at 4–7 week intervals are typical. Alexandrite lasers carry moderate burn and hyperpigmentation risk in this range.
Fitzpatrick V–VI (dark brown to very dark skin) must use Nd:YAG 1064nm exclusively. The longer wavelength bypasses epidermal melanin and targets the hair follicle directly. 8–12 sessions at 4–6 week intervals are typical. Pre-treatment with hydroquinone cream further reduces post-inflammatory hyperpigmentation risk (NCBI NBK557626).
Hair colour, hormones, and treatment area
Black and dark brown hair absorb the most laser energy and respond best. Medium brown responds well. Light brown may need more sessions. Blonde, red, and grey/white hair contain insufficient melanin (pheomelanin or none) for effective laser targeting — electrolysis is the recommended alternative.
Hormonal areas (face, bikini, underarm, chest) may require 1–2 additional sessions due to androgen-driven regrowth. PCOS and high testosterone conditions can add 2–3 sessions and often require ongoing maintenance every 6–12 months. Non-hormonal areas (legs, back, arms) respond more predictably.