--- title: "Comparative Advantage and the Gains from Trade" description: "With different opportunity costs, countries can gain by specialising where their sacrifice is lower than their partner's and trading on suitable terms. This can expand consumption beyond domestic prod" canonical: https://lightmysky.com/learn/civics-and-economics/comparative-advantage-and-the-gains-from-trade-mt_gcGxu7E2Y8 source: https://lightmysky.com/learn/civics-and-economics/comparative-advantage-and-the-gains-from-trade-mt_gcGxu7E2Y8.md retrieved: 2026-11-12 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Comparative Advantage and the Gains from Trade With different opportunity costs, countries can gain by specialising where their sacrifice is lower than their partner's and trading on suitable terms. This can expand consumption beyond domestic production limits, even if one country has absolute advantage in both goods. A tariff can reduce these gains. Subject: Civics & Economics · Area: Economics · Ages 15 to 16 Page: https://lightmysky.com/learn/civics-and-economics/comparative-advantage-and-the-gains-from-trade-mt_gcGxu7E2Y8 ## Ready when they can - Work out each country's opportunity cost from an output table and say who should specialise in what - Show with figures that both countries can end up with more of both goods than before trade - Explain why being better at everything does not remove the case for trading ## Lesson: Why even the best can gain by trading Phones and shirts use resources that could make other goods. Recall opportunity cost: the next best alternative given up. Absolute advantage means producing more with the same resources. Comparative advantage means a lower opportunity cost than the trading partner. In a two-good model, compare what each country sacrifices per unit. With different opportunity costs, specialisation and suitable trade can benefit both countries. **Example.** Suppose one worker per country works one day with constant trade-offs. Cora can make 12 wheat or 4 cloth; Dara can make 4 wheat or 8 cloth. One cloth costs Cora 12 ÷ 4 = 3 wheat and Dara 4 ÷ 8 = 0.5 wheat. Dara has the comparative advantage in cloth. Cora gives up less cloth per wheat, so has the comparative advantage in wheat. Divide the forgone output by the gained output. Absolute advantage in both goods need not prevent gains: different opportunity costs give each partner comparative advantage in one good; identical costs give no such gains here. With each worker splitting time equally, Cora has 6 wheat, 2 cloth; Dara 2 wheat, 4 cloth. Specialisation gives Cora 12 wheat and Dara 8 cloth. Exchanging 4 wheat for 3 cloth leaves Cora 8 wheat, 3 cloth; Dara 4 wheat, 5 cloth. Both have more of both goods. Other starting mixes need not do so. Trade can expand consumption beyond domestic production limits, but does not expand productive capacity or necessarily increase consumption of every good. With constant opportunity costs and no trade costs, both gain only if the swap rate lies strictly between their opportunity costs. A tariff taxes imports. If it blocks a mutually beneficial exchange, countries lose gains from specialisation. Protection may help domestic producers while consumers lose access to cheaper imports. **Recap.** Compare opportunity costs between partners. Trade can expand consumption choices when its gains exceed its costs. ## Practice 8 questions on this page, each with its working shown. ## Needs first - [Taxes, Public Spending and the Government Budget](https://lightmysky.com/learn/civics-and-economics/taxes-public-spending-and-the-government-budget-mt_OEjK6v1-F0) - [Scarcity, Opportunity Cost and the Production Frontier](https://lightmysky.com/learn/civics-and-economics/scarcity-opportunity-cost-and-the-production-frontier-mt_p_c7nNzHEw) ## Optional connections - [Trade Policy and Barriers](https://lightmysky.com/learn/civics-and-economics/trade-policy-and-barriers-mt_l_l6qXfRle) ## Opens up - [Where Your Things Are Actually Made](https://lightmysky.com/learn/geography/where-your-things-are-actually-made-mt_d1ovR3Nk3S) - [Silver, Sugar and Early Global Trade](https://lightmysky.com/learn/history/silver-sugar-and-early-global-trade-mt_uFhCt_GXgN)