How long does calculus take to form on the tooth?

• A. 2-3 days
• B. 1 day
• C. 1 week
• D. 1 month

Answer: (A)

Calculus forms from mineralization of dental plaque. After plaque begins to accumulate on a tooth, mineral deposits in saliva start to harden the plaque within roughly 24 to 72 hours, so the hard tartar form typically appears in about 2–3 days. That makes the 2–3 day window the best fit among the options. A one-day timeframe is usually too short for meaningful mineralization, while a week or a month would imply much more buildup than what early calculus shows. Keep in mind that actual timing can vary with hygiene, diet, and saliva composition, but the general window for initial calculus formation is about 2–3 days.