How to say "approximation" in Japanese

• 概算がいさんCommon
  noun, suru verb, transitive verbCovers approximation in the sense of a rough numerical calculation: a ballpark figure for a cost, amount, or quantity. Typical when estimating a budget or price roughly before exact figures are available.
  この国くにの人口じんこうは概算がいさん５千万ごせんばんに達たっする。↗

  The population of the country is roughly estimated at 50,000,000.
• 目安めやすJLPT N2approx.Common
  nounCovers approximation as a rough guide or yardstick: a figure serving as a rough standard to aim at or judge by, not a calculated result. Typical when indicating roughly how long a task takes.

Use 概算 for an approximation that is a rough calculation of a figure such as a cost or amount, and 目安 for an approximation that serves as a rough guide or yardstick to judge by.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 概算がいさんapproximation
• 近似きんじapproximation
• 近似値きんじちapproximate value
• 目安めやすrough estimate