需求

Each pop in the game has needs, representing their consumption of trade goods. These needed goods vary based on their standard of living. Most needs can be fulfilled by a range of different goods, so there is some flexibility for pops to deal with surpluses and shortages.

A big proportion of the economy in Victoria 3 is based uppon the simulation of pops earning money through work (starts with subsitance farming, so doesn't even require buildings!) and then spending this money to buy (and "consume") goods! Consequently is of a great importance how much money your pops have (determined by having work and the amount of wages being paid) and how much money the goods cost (in their market, there is no world market!).

The main component of the current price of a good on a certain market, is of course the ratio between supply and demand. But Trade routes – which can be started and stopped anytime – affect the price as well. Then there are Trade#Tariffs.

In order to fulfill their needs, pops purchase goods or their substitutes until the volume of purchased goods multiplied with their base cost reaches a value that is set per need type for each wealth level. As a consequence, goods with a higher base price are needed in lower amounts to fulfill the same need - for example, 10 units of meat (base price of 30 -> 30 * 10 = 300 need fulfilled) satisfy the same amount of food need as 15 units of grain (base price of 20 -> 20 * 15 = 300 need fulfilled).

The calculation of need fulfillment is solely based on purchased amount, base price and potentially obsessions/taboos.

Need types

Different goods can have different weights. These weights, together with market data, are used by pops to make decisions on the split of purchases between different goods within a need type. The exact formula for this decision is unknown and possibly bugged, but a larger weight value generally makes pops prioritize a good.

Most needs cannot be fully met by any single good. For example, a pop's demand for household goods cannot be met by an unlimited supply of glass — they'll also want at least some amount of furniture and/or paper.

By default, all items below are weighted equally, and can be used to fulfil up to 80% of the need (100% if the category only contains one good), with no minimums. Exceptions are noted below.

Pop needs

Need	Standard of Living
	Starving	Struggling	Impoverished	Middling	Secure	Prosperous	Affluent	Wealthy		Lavish	Opulent
	1 – 4	5 – 9	10 – 14	15 – 19	20 – 24	25 – 29	30 – 39	40 – 44	45 – 49	50 – 59	60 +
Basic Food	(20) (20) (30, weight ×0.5, max 40%) (30, weight ×0.5, max 40%) (30)						—
Luxury Food	—				(30, max 40%) (30, max 40%) (30, max 40%) (30, weight ×0.5, max 40%)
Simple Clothing	(20) (30)			—
Standard Clothing	—		(30)					—
Crude Items	—	(20) (30)		—
Household Items	—		(30, minimum 5%) (40) (30, weight ×0.5, max 40%)						—
Luxury Items	—			(60, minimum 5%, max 40%) (60, minimum 5%, max 40%) (70, minimum 5%, max 40%) (80, max 40%)
Heating	(20, max 60%) (20, max 60%) (30, max 60%) (40, max 60%) (30, weight ×2, max 100%)
Intoxicants	(30, max 60%) (40, max 60%) (50, max 60%)
Luxury Drinks	—			(50, max 60%) (50, max 60%) (50, max 60%)
Services	—		(30)
Free Movement	—			(30, weight ×0.1) (30) (100)
Communication	—				(30, weight ×0.1) (30, weight ×0.1) (70)
Art	—						(30, weight ×0.05) (200)
Need	1 – 4	5 – 9	10 – 14	15 – 19	20 – 24	25 – 29	30 – 39	40 – 44	45 – 49	50 – 59	60 +
	Starving	Struggling	Impoverished	Middling	Secure	Prosperous	Affluent	Wealthy		Lavish	Opulent
	Standard of Living

Specific pops

Peasants

Peasants, i.e. population working on subsistence buildings, buy from market 10% of what a pop belonging to a profession would normally buy.

Dependents

Dependents per person need half of the consumer goods that a working adult normally requires. The default dependents to employed ratio is 3 (75% dependents, 25% working adults). For example, a pop with 10,000 people may have 2,500 working adults and 7,500 dependents. This would mean that the consumption by working adults is 40% of the pop while dependents consume 60% of the consumer goods.

Exact numbers for consumption

Exact number of goods that pops will consume is dependent on their wealth level, and the weight factor that they put on each goods.

The wealth level decides the standard pop needs package that Pops will consume, which is defined as cost that 10,000 pops will need to pay per category of needs to maintain their wealth level, when all goods are at their Base Price. This information is listed in Victoria 3\game\common/buy_packages/00_buy_packages.txt. Pops will then purchase various Goods for a Needs Category so that the cost of goods at base price (NOT current price) will add up to the value defined on the standard pop needs package. The distribution (weight) of goods that will be purchased within a category is saved per culture at state level in the save file, under the states database.

This means that for specific goods being purchased for specific needs category for 10,000 pops, the equation is

[math]\displaystyle{ Cost\ of\ goods\ purchased\ at\ base\ price=\left ( \frac{Weight\ of\ goods}{Sum\ of\ all\ weights\ in\ category}\right ) \times Total\ cost\ of\ category\ in\ package }[/math].

And given that cost of goods is equal to the price of goods multiplied by volume of goods purchased, for 10,000 Pops:

[math]\displaystyle{ Volume\ of\ goods\ purchased=\frac{1}{Base\ price\ of\ goods}\times \left ( \frac{Weight\ of\ goods}{Sum\ of\ all\ weights\ in\ category}\right ) \times Total\ cost\ of\ category\ in\ package }[/math]

Finally, the size of Population can be factored in. In all Pops, 10,000 Workforce will require 1 standard Needs package, while their Dependents will only require 0.5 standard Needs Package for the same number, which means that

[math]\displaystyle{ Volume\ purchased\ by\ specific\ Pops=\frac{Workforce + 0.5 Dependents}{10000}\times \frac{1}{Base\ price\ of\ goods}\times \left ( \frac{Weight\ of\ goods}{Sum\ of\ all\ weights\ in\ category}\right ) \times Total\ cost\ of\ category\ in\ package }[/math]