Calculating an "appropriate" level of tariffs for the U.S. to impose on other countries is a complex task that involves economic, political, and strategic considerations. However, if you're looking for a simple, conceptual framework to understand how tariffs might be determined, here’s a basic approach. Note that this is a simplification and real-world tariff policies require detailed analysis, data, and consideration of trade agreements, international law, and economic impacts.

Simple Framework for Calculating Tariffs
Identify the Goal of the Tariff
Tariffs can serve different purposes, such as protecting domestic industries, retaliating against unfair trade practices, or generating revenue. The goal will influence the tariff rate. For example:
To protect a domestic industry, you might calculate a tariff to offset the price advantage of foreign goods.
For retaliation, you might mirror the tariffs or subsidies of the other country.
Determine the Price Differential (if protecting domestic industries)
If the goal is to protect a U.S. industry, a simple method is to calculate the difference between the cost of producing a good domestically and the cost of the imported good.
Formula:
Tariff (%) = [(Domestic Production Cost - Foreign Import Price) / Foreign Import Price] × 100
Example: If a U.S.-made widget costs $10 to produce, but a foreign widget costs $8, the tariff to "level the playing field" would be:
[($10 - $8) / $8] × 100 = 25% tariff.
Consider Trade Imbalances (if addressing trade deficits)
If the goal is to reduce a trade deficit with a specific country, you might estimate a tariff rate that discourages imports while encouraging exports. A simplistic approach could involve:
Looking at the trade deficit with the country (e.g., U.S. imports $100 billion more from Country X than it exports to them).
Estimating how much import reduction is needed to balance trade, then applying a tariff to achieve that reduction (requires data on price elasticity of demand for imports).
Mirror Unfair Practices (if retaliatory)
If another country imposes tariffs, subsidies, or other trade barriers on U.S. goods, a simple retaliatory tariff could mirror their policies. For example:
If Country X imposes a 20% tariff on U.S. cars, the U.S. could impose a 20% tariff on Country X’s cars.
Account for Consumer and Economic Impact
Even in a simple model, consider the potential downsides of tariffs, such as higher prices for U.S. consumers or retaliation from trading partners. A basic rule of thumb is to keep tariffs low enough to avoid significant inflation or supply chain disruptions, but this requires more detailed economic modeling.
Important Caveats
Data Requirements: Real-world tariff calculations require detailed data on production costs, import/export volumes, price elasticities, and global supply chains.
WTO Rules: The U.S. is a member of the World Trade Organization (WTO), which sets rules for tariffs and trade practices. Tariffs must comply with WTO agreements, or they risk legal challenges and retaliation.
Unintended Consequences: Tariffs can lead to higher consumer prices, reduced export competitiveness, and trade wars, so simplistic calculations may not capture the full economic impact.
Political and Strategic Factors: Tariffs are often influenced by diplomatic relations, national security concerns, and domestic political pressures, not just economic calculations.
Example of a Simplified Tariff Calculation
Let’s say the U.S. wants to protect its steel industry from cheap imports from Country Y:

U.S. steel production cost: $500 per ton.
Country Y’s steel import price: $400 per ton.
Tariff to offset the price advantage: [($500 - $400) / $400] × 100 = 25%.
So, a 25% tariff on Country Y’s steel would theoretically make U.S. steel competitive. However, this doesn’t account for potential retaliation, consumer price increases, or global supply chain effects.

Better Approach
For a more accurate and practical tariff policy, governments and economists use sophisticated models, such as computable general equilibrium (CGE) models, to simulate the effects of tariffs on trade, prices, employment, and GDP. These models require extensive data and expertise, but they provide a more comprehensive view of the impacts.

If you’re interested in a specific industry or country, providing more details could help refine this simplified approach. Alternatively, consulting resources like the U.S. International Trade Commission (USITC) or economic think tanks can provide data-driven insights into tariff policies.