How Long Does It Take to Grow Nails?

Quick Answer

3.5 mm per month is the average fingernail growth rate — roughly 1 mm per week. Toenails grow more slowly at about 1.6 mm per month. A completely lost fingernail takes 3–6 months to fully regrow, while a toenail takes 12–18 months. Growth rate varies by age, health, nutrition, and which finger or toe.

Nail Growth Rates by Finger

Not all nails grow at the same speed. The middle finger nail grows fastest, and the pinky nail grows slowest.

Nail	Average Growth Rate	Full Regrowth Time
Middle finger	~3.7 mm/month	3–4 months
Index finger	~3.5 mm/month	3–5 months
Ring finger	~3.4 mm/month	4–5 months
Thumb	~3.2 mm/month	4–6 months
Pinky finger	~3.0 mm/month	4–6 months
Big toenail	~1.6 mm/month	12–18 months
Small toenails	~1.0–1.4 mm/month	12–18 months

Factors That Affect Nail Growth

Age

Nail growth peaks in your 20s and 30s, then gradually slows. Children's nails grow faster than adults', and elderly individuals may see growth rates drop by 30–50% compared to young adults. A 2009 study in the Journal of the European Academy of Dermatology and Venereology found that average fingernail growth had actually increased by about 25% compared to measurements from the 1930s, potentially due to improved nutrition.

Dominant Hand

Nails on your dominant hand grow slightly faster than those on your non-dominant hand, likely due to increased blood flow from more frequent use and minor trauma (like typing).

Season

Nails grow faster in summer than winter. Warmer temperatures increase blood circulation to the extremities, promoting growth. The difference is modest but measurable — roughly 10–15% faster in warm months.

Hormones and Health

• Pregnancy often accelerates nail growth due to increased blood volume and hormonal changes
• Thyroid disorders can slow growth (hypothyroidism) or cause brittle nails
• Poor circulation reduces growth rate, which is partly why toenails grow slower than fingernails
• Fever or serious illness can temporarily halt nail growth, sometimes leaving horizontal ridges (Beau's lines) that grow out over months

Nutrition

Certain nutrients are essential for healthy nail growth:

• Biotin (vitamin B7): The most well-studied supplement for nail strength. A dose of 2.5 mg/day has been shown to improve nail thickness by 25% in some studies.
• Protein: Nails are made of keratin, a protein. Inadequate protein intake can slow growth and cause brittle nails.
• Iron: Iron deficiency can cause spoon-shaped nails (koilonychia) and slow growth.
• Zinc: Deficiency causes white spots and slowed growth.
• Vitamin C: Important for collagen production around the nail bed.

Nail Regrowth After Injury

Minor damage (cracked or broken nail)

A crack at the free edge grows out in 2–4 weeks. A break near the cuticle takes 3–4 months to fully grow past the fingertip.

Complete fingernail loss

If a fingernail is completely avulsed (torn off), the new nail begins growing from the nail matrix within 1–2 weeks, but it takes 3–6 months for the nail to fully regrow to its normal length. The new nail may appear slightly different in texture or shape for several growth cycles.

Complete toenail loss

A lost toenail takes 12–18 months to fully regrow. The big toenail is the slowest, sometimes requiring 18 months or more. During regrowth, the nail may appear thickened, ridged, or discolored — this is normal and usually resolves after 1–2 complete growth cycles.

After fungal infection treatment

Even after antifungal medication clears the infection, it takes a full growth cycle for the damaged nail to be replaced by healthy nail. This means 3–6 months for fingernails and 12–18 months for toenails before you see a completely clear nail.

Tips to Promote Healthy Nail Growth

• Keep nails hydrated — apply cuticle oil or moisturizer regularly, especially in winter
• Eat a balanced diet rich in protein, biotin, iron, and zinc
• Avoid harsh chemicals — wear gloves when cleaning or using solvents
• Don't bite your nails — habitual biting damages the nail matrix and can permanently alter growth
• File in one direction — sawing back and forth can cause splitting
• Take breaks from polish — constant gel or acrylic nails can thin the nail plate over time
• Stay hydrated — dehydration makes nails brittle and more prone to breakage

When to See a Doctor

Certain nail changes warrant medical attention:

• Dark streaks under the nail (melanonychia) — could indicate melanoma
• Nails separating from the nail bed (onycholysis) — may signal thyroid issues or fungal infection
• Pitting — small dents can indicate psoriasis
• Spoon-shaped nails — associated with iron deficiency anemia
• Yellow, thickened nails — likely fungal infection requiring treatment
• Nail not regrowing after 6 months (finger) or 18 months (toe) post-injury — the nail matrix may be damaged