How to Calculate Tax Incidence

Tax incidence splits a per-unit tax by elasticity: consumer burden = new price paid − old price, producer burden = old price − new net price.

Formula

Consumer burden per unit = P(paid, after tax) − P(before tax)
Producer burden per unit = P(before tax) − P(received, after tax)
Consumer burden + Producer burden = tax per unit
Burden rule: Consumer burden ÷ Producer burden = Es ÷ Ed (the more inelastic side pays the larger share)

Steps

1
Find the pre-tax price. Read the equilibrium price before the tax, where supply meets demand. This is the baseline both sides start from.
2
Find the price consumers pay after the tax. A per-unit tax shifts supply up (or demand down) by the tax amount. Read the new, higher price buyers pay on the demand curve at the new quantity.
3
Find the price producers keep after the tax. Subtract the tax from the price consumers pay: P(received) = P(paid) − tax. This is what sellers actually keep per unit.
4
Split the burden. Consumer burden = P(paid) − P(before); producer burden = P(before) − P(received). The two burdens add up to the per-unit tax.
5
Check against elasticity. The more inelastic side bears the larger share. Whoever can least change their quantity (steeper curve) pays more of the tax.

Worked example

A market sits at equilibrium price $10. The government puts a $3 per-unit tax on producers, which shifts supply up. The new price consumers pay rises to $12, and producers receive $12 − $3 = $9. Consumer burden = $12 − $10 = $2 per unit. Producer burden = $10 − $9 = $1 per unit. Check: $2 + $1 = $3, the full tax. Consumers bear $2 of every $3 (two-thirds) and producers bear $1 (one-third), so demand is more inelastic than supply. The burden ratio $2 ÷ $1 = 2 equals Es ÷ Ed, meaning supply is twice as elastic as demand (Es = 2 × Ed).

Frequently asked questions

What does tax incidence tell you?

Tax incidence tells you who actually bears the cost of a tax, regardless of who legally pays it to the government. The more inelastic side of the market (the one that changes quantity the least) bears the larger share, because they cannot easily avoid the tax by buying or selling less.

Does it matter whether the tax is placed on buyers or sellers?

No. The legal (statutory) incidence does not change the economic incidence. Whether the tax is levied on producers or consumers, the same relative elasticities determine how the burden splits, and buyers and sellers end up paying the same shares either way.

When do consumers bear the entire tax?

Consumers bear the whole tax when demand is perfectly inelastic (a vertical demand curve) or supply is perfectly elastic (a horizontal supply curve). In both cases the price consumers pay rises by the full tax amount and producers keep the same net price.

How does tax incidence relate to deadweight loss?

Both come from the same tax wedge between the price buyers pay and the price sellers receive. The burden split is that wedge times the units still traded; the deadweight loss is the triangle over the units no longer traded because of the tax.

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