Use this chemistry calculator to reproduce a named relationship with explicit quantities and units for study, laboratory planning, or an independent numerical check.

Limiting reagent (mol)

Moles of the limiting reagent consumed.

Limiting coefficient

Stoichiometric coefficient of the limiting reagent; must be nonzero.

Excess coefficient

Stoichiometric coefficient of the excess reagent; must be nonzero.

Excess available (mol)

Starting moles of the excess reagent.

Compute the leftover moles of an excess reagent after complete consumption of the limiting reagent. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Excess remaining (mol)

Moles of the excess reagent remaining after reaction.

• Stoichiometric results assume the balanced reaction, stated purity, and complete conversion to the selected products. Yield, selectivity, side reactions, moisture, and measurement uncertainty must be handled separately.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check units and significant figures, compare the result with limiting cases, and use measured or source-specific constants where available. Laboratory, safety, and regulatory decisions require validated methods and appropriate uncertainty analysis.

• Excess Reagent Moles Remaining Calculator

  Compute the moles of excess reagent left over after the limiting reagent is fully consumed.

• Excess Reagent Mass Remaining Calculator

  Convert the leftover moles of an excess reagent into mass using its molar mass.

• Limiting Reagent Finder

  Identify the limiting reagent and the product amount for a reaction needing ratioAB moles of B per mole of A.