›to say what you believe the cost, size, value, etc. of something is, although you do not know for certain: estimate how much/manyWe should be able to estimate how many customers we will have each month.Several online calculators allow you to estimate your carbon emissions.estimate that sthSome analysts estimate that about a quarter of career-track hires in recent years have been women.estimate sth to be sthThe knock-on economic benefit is estimated to be about 1200 jobs.estimate sth at sthGlobal oil reserves were estimated at 1,000 billion barrels.