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The Education Cost Sharing (ECS) formula is the method the State of Connecticut has established to distribute approximately $2.2 billion annually in state education funding. The ECS formula is used exclusively to provide state funding to local and regional public school districts.

The ECS formula is made up of several different components: the foundation, student need-based weights, the Base Aid Ratio, and the phase-in schedule. This page provides an overview of each of these components and how they impact students, schools, and communities.


In an education funding formula, the foundation amount is intended to represent the estimated cost of educating a general education student who does not have any additional learning needs.

The foundation in the ECS formula is $11,525 per student. Additionally, the foundation “incorporates” the State’s share of general special education funding, resulting in approximately 22% of the ECS foundation amount being attributable to special education.


Students with certain learning needs are more likely to need additional resources in order to have equal access to educational opportunities. In order to assist districts and schools serving students with higher learning needs, school funding formulas often include weights for specific student needs.

Weights are used in school funding formulas to drive greater funds to students (ex. low-income students, multilingual learners, students with disabilities) who have been found to require additional resources and educational supports to achieve at the same levels as their non-need peers.

The ECS formula contains three “need-student” weights, which increase per-student state education aid for students with additional learning needs. Below is a description of each of the weights in the ECS formula.

Low-Income Student Weight

  • Increases foundation amount by 30 percent for students who live in economically disadvantaged households as measured by eligibility for free or reduced-price lunch (FRPL)

Concentrated Poverty Weight

  • Increases foundation amount an additional 15 percent (for a total of 45 percent) for economically disadvantaged students residing in districts where 60 percent or more of the enrollment is considered economically disadvantaged
  • Weight applies only to a district’s low-income students above the 60-percent level

Multilingual Learner Weight

  • Increases foundation amount by 25 percent for students who are identified as needing additional English-language skills

Base Aid Ratio

The Base Aid Ratio is the variable in the ECS formula that determines each community’s ability to financially support its public schools. The Base Aid Ratio acts as an equity metric to distribute state education funding through the ECS formula, with the towns with the least ability to fund their public schools receiving the most state aid.

The Base Aid Ratio uses two elements to calculate a town’s ability to fund its public schools: a property wealth factor and an income wealth factor. The property wealth factor counts for 70% in determining a town’s Base Aid Ratio, while the income wealth factor counts for 30%. Below is a description of both factors.

Property Wealth Factor

  • Counts for 70% of a town’s Base Aid Ratio
  • Determined using a town’s Equalized Net Grand List per Capita (ENGLPC), compared to the state median town ENGLPC
  • ENGLPC is the amount of taxable property (at 100 percent of fair market value) per person in a city or town

Income Wealth Factor

  • Counts for 30% of a town’s Base Aid Ratio
  • Determined using a town’s Median Household Income (MHI), compared to the state median MHI
  • MHI refers to the income level earned by a given household where half of the homes in the area earn more and half earn less

PIC Index Bonus

The ECS formula also adds additional funding for communities that have one of the highest Public Investment Communities (PIC) index scores. Under the formula, if a town has one of the 19 highest PIC index scores, the town receives a bonus of three to six percentage points to its Base Aid Ratio — resulting in increased state education aid to the town. The chart below outlines the additional percentage point bonus towns with one of the 19 highest PIC index scores will see added to their Base Aid Ratio.

PIC Index Bonus

Phase-in Schedule

The ECS formula is currently being phased in over time with the phase-in schedule differing between towns receiving — according to the formula — an increase in funding and those receiving a decrease. The phase-in began in fiscal year 2019 and, for towns receiving increases, will be complete in FY 2026.

As part of the state's budget for FYs 2024 and 2025, towns that are overfunded according to the ECS formula, and would normally experience decreases in their ECS funding, are “held harmless." This means for FYs 2024 and 2025, these towns will not experience decreases in their ECS funding as previously planned and instead receive the same grant amount they received in FY 2021. The formula’s phase-out schedule will resume in FY 2026 and proceed until full funding is reached in FY 2032.

There is also a hold harmless provision for Alliance Districts, which are identified as among the lowest-performing school districts in the state. Alliance Districts that would otherwise receive a decrease in ECS funding, according to the formula, are permanently held harmless to the greater of their FY 2017 ECS grant amount, prior year ECS grant, or current year ECS grant.

Below is a table detailing the ECS formula’s phase-in schedule.

It is important to remember the ECS formula is calculated on an annual basis using updated district and town data. As a result, a town’s calculated ECS grant will change as its district and town inputs change. Additionally, as a town’s calculated ECS grant changes, so does the difference between the town’s calculated ECS grant and its prior year ECS grant, which impacts the phase-in schedule of the town’s grant.

Other Formula Components

Regional District Bonus

The Regional District Bonus provides additional funding to towns that send students to a regional school district or one of Connecticut's three endowed academies. The Regional District Bonus is scaled based on the number of student grades educated by the regional school district or endowed academy. Towns receive $100 for each student and each grade sent to a regional school district or endowed academy.

For example, a town sending 10 students to a regional high school (four grades) would receive $100 x 10 students x 4 grades = $4,000. The Regional District Bonus is calculated prior to the ECS phase-in, which means this example town would not receive the entire $4,000 prior to the ECS grant being fully funded.

Statewide Guaranteed Wealth Level (SGWL)

Commonly referred to as the threshold factor, the SGWL determines each town’s ECS aid percentage. Each town’s ability to support its public schools (as determined by the Base Aid Ratio) is compared to the SGWL to determine what percentage of the per-student funding amount the town will receive from ECS aid and what will have to come from local tax dollars. As the SGWL is lowered, and all other formula factors remain constant, the formula distributes education aid more equitably.

Minimum Aid Ratio

Under the ECS formula, all districts are guaranteed some state education aid, even when the result of the ECS formula calculation would be that a town would not be entitled to receive ECS grant funding. This guarantee is the result of the formula’s Minimum Aid Ratio, which is 10% for Alliance Districts and Priority School Districts and 1% for all other districts.

Page Sources

Conn. Gen. Statutes ch. 172, §§ 10-262f, 10-262h.

Connecticut General Assembly, Office of Fiscal Analysis and the Office of Legislative Research. (2014). CT Special Education Funding. Retrieved from

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