| Example | The teacher estimated that the test would take 30 minutes. |
| Example | Experts estimate the bridge will cost $2 million to build. |
| Example | Scientists estimate the Earth is 4.5 billion years old. |
| estimated | verb |
| estimates | noun/verb |
| estimating | verb |
| estimation | noun |
| estimations | noun |
| approximate |
| calculate |
| guess |
| exact |
| precise |
| estimate the cost | The engineers estimated the cost of construction at $5 million. | Engineering, economics |
| estimate the number | The researchers estimated the number of species in the forest. | Biology, ecology |
| estimate the effect | The study estimated the effect of smoking on lung cancer risk. | Medicine, health sciences |
| estimate the value | Economists estimated the value of lost productivity. | Economics, business |
| estimate the risk | Doctors estimated the risk of infection after surgery. | Medicine, public health |
| Professional Culture | In English-speaking work settings, to estimate means an informed approximation — not a wild guess. Providing an estimate implies expertise and responsibility. |
| Academic Culture | Researchers use estimate to show transparency: results are approximations, not exact numbers. Anglo-American academic culture values being explicit about uncertainty. |
| Everyday Life | In daily English, estimate is used for time and cost (How long do you estimate it will take? Can you estimate the cost?). Simpler synonyms like guess are more informal. |
| Business / Services | In business, giving an estimate is standard practice, especially in trades (repairs, construction). Customers expect estimates before work begins. |
| Statistics | Refers to calculating approximate values of parameters. | The researchers estimated the mean income using sample data. |
| Economics | Refers to forecasting costs, values, or market sizes. | The firm estimated future growth at 3% annually. |
| Medicine / Health Sciences | Refers to calculating risks, survival rates, or treatment effects. | Doctors estimated the survival rate at 80%. |
| Engineering / Construction | Refers to calculating costs, time, or resources for a project. | The architects estimated the project would take two years. |
| Environmental Science | Refers to approximating impacts or population sizes. | The team estimated carbon emissions from deforestation. |
| estimar | Direct equivalent; used in academic, professional, and everyday contexts. | EN: Scientists estimate the Earth is 4.5 billion years old. PT: Os cientistas estimam que a Terra tenha 4,5 bilhões de anos. |
| calcular aproximadamente | Used to emphasize the process rather than the result. | EN: The engineers estimated the cost of repairs. PT: Os engenheiros calcularam aproximadamente o custo dos reparos. |
| avaliar | Sometimes used in everyday Portuguese when estimate means giving an approximate evaluation. | EN: She estimated the number of guests at 100. PT: Ela avaliou o número de convidados em 100. |
| supor / achar | Informal, weaker equivalent — but not accurate in academic contexts. | EN: I estimate it will take an hour. PT (informal): Eu acho que vai levar uma hora. |