Percent Yield Calculator

How to use this calculator

Enter the actual yield you obtained and the theoretical yield calculated from stoichiometry. Or enter an expected percent yield to see how much product to expect.

Formula

% yield = actual ÷ theoretical × 100

Worked example

Theoretical yield 10.0 g, actual product 8.5 g:

% yield = 8.5 ÷ 10.0 = 85%

Finding the theoretical yield

1. Convert the limiting reagent’s mass to moles (use the moles calculator).
2. Use the balanced equation’s mole ratio to find moles of product.
3. Multiply by the product’s molar mass.

Typical yields

Simple one-step lab reactions often give 70–95%. Multi-step syntheses multiply losses: five steps at 80% each give an overall yield of only 33%.

Frequently asked questions

What is percent yield?

How much product you actually obtained compared with the maximum possible, × 100.

Why is yield usually below 100%?

Incomplete reactions, side reactions, and product lost during filtering, transfer or purification.

Can yield be over 100%?

Only through error — usually the product is still wet or contains impurities.

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