What is the percent yield formula?

Percent yield equals the actual yield divided by the theoretical yield, multiplied by 100. The actual yield is what you measured; the theoretical yield is the maximum predicted by the balanced equation.

Can percent yield exceed 100 percent?

In theory no, but a value above 100 percent usually signals an impure or wet product, or a weighing or measurement error.

How do I find the actual yield from percent yield?

Rearrange the formula: actual yield = (percent yield ÷ 100) × theoretical yield. Select "actual yield" in the tool and it does this for you.

How do I find the theoretical yield?

Theoretical yield = actual yield ÷ (percent yield ÷ 100), or actual ÷ percent × 100. It is the maximum mass of product the balanced equation allows from your limiting reactant.

What is the difference between actual and theoretical yield?

Theoretical yield is the amount of product predicted by stoichiometry assuming a perfect reaction. Actual yield is the amount you really recover, always equal to or less than theoretical because of side reactions, losses and incomplete reactions.

Do both yields need the same units?

Yes — use the same unit for both (usually grams or moles). Since percent yield is a ratio, the units cancel, so any consistent unit gives the same percentage.

Percent Yield Calculator

Q: Is my data uploaded?

No. The calculation runs entirely in your browser and nothing is sent anywhere.

Percent yield calculator

Percent yield measures how efficient a chemical reaction was by comparing the actual yield you recovered in the lab against the theoretical yield predicted by the balanced equation. It is a core quantity in stoichiometry, chemistry coursework and process work, where a low percent yield points to losses or side reactions.

How it works

The tool uses one relationship and rearranges it to solve for whichever value you leave blank:

percent yield     = actual ÷ theoretical × 100
actual yield      = (percent ÷ 100) × theoretical
theoretical yield = actual ÷ percent × 100

Choose the unknown from the dropdown, enter the two values you know, and the result appears instantly. Both yields must use the same unit; because it is a ratio, the units cancel.

Example

You expected 10 g (theoretical) and recovered 8.2 g (actual):

Percent yield: 8.2 ÷ 10 × 100 = 82%

Solving the other way — 82% yield with a 10 g theoretical gives 8.2 g actual; 8.2 g actual at 82% gives a 10 g theoretical.

Actual	Theoretical	Percent yield
8.2 g	10 g	82%
4.5 g	5 g	90%
9.9 g	10 g	99%

The calculation runs entirely in your browser and nothing is sent anywhere.