Estimation is the process of finding a usable approximation of a result.

Estimation may also refer to:

• Estimation theory, a field in statistics, also used in signal processing
• Estimation statistics, a data analysis approach in frequentist statistics
• Estimation (project management)
• Approximation, finding estimates in the form of upper or lower bounds for a quantity that cannot readily be evaluated precisely
• Forecasting
• Prediction

• Guesstimate, an informal estimate when little information is available