Chalkline — Field Guide

Field Guide · How the model works

Every classroom is a business unit.

Chalkline turns a school's roster into a financial model — making visible something most schools never see at a granular level: which grades, classrooms, or sections actually carry their cost, and what the real financial consequence of an enrollment or discounting decision is. This guide explains every screen, every lever you can pull, and exactly how each number is calculated, for both the K–8 and high school editions.

lever = an input you control output = a figure the model computes

What Chalkline is

Chalkline is a strategic revenue model for schools. It sits at the layer your CRM doesn't cover: not who's in the funnel, but what each enrollment and pricing decision does to net tuition revenue. It treats every teaching unit as a small business with its own profit-and-loss, then rolls those up into the whole-school picture.

Two editions, one spine

Edition	Business unit	Fits	Why it differs
K–8 · Classroom	The classroom	Early childhood through middle school	A cohort moves together through one room for the year, so the room is the natural P&L.
High School · Section	The course section	Grades 9–12	A ninth grader doesn't sit in one room all day, so cost and revenue re-base on the section, and every roll-up (grade, department, teacher) is a grouping of sections.

Chalkline is a planning model, not an accounting system. It's built to make trade-offs visible and to pressure-test decisions — not to replace your general ledger or your SIS. Everything is editable; the seeded numbers are realistic stand-ins you replace with your own.

The mental model

A teaching unit (room or section) "rents" a fixed block of capacity — a teacher, a slice of the building — whether or not every seat is filled.
An empty seat is pure waste. A discounted or aided student is accretive — the marginal cost of one more body is small — right up until they tip the unit past its break point and force more capacity.
Schools live on collected tuition, not sticker price, so the net-tuition ratio is a first-class number everywhere.
A student who leaves forfeits not one year of tuition but the whole remaining contract. That reframing — Total Contract Value — is the centerpiece.

The financial spine

Seven concepts run through every screen in both editions. Understand these and the rest of the tool reads naturally.

1 · Net tuition & the net tuition ratio

Sticker (list) tuition is what you publish. Net tuition is what you actually collect after financial aid and discounts. The ratio between them is treated as a headline number, not a footnote.

# for any unit or the whole school net tuition ratio = tuition collected ÷ sticker tuition

2 · Capacity cost vs. variable cost

Costs split into two kinds. Capacity cost (the teacher, the allocated overhead) is sunk on the unit whether or not it fills. Variable cost (materials, technology, food, activities) scales with every enrolled head. The distinction is what makes a marginal student accretive.

variable cost = enrolled students × variable cost per student total cost = capacity cost + variable cost

3 · Contribution margin

The single most useful per-student number: what one more student contributes toward covering capacity cost, after their own variable cost is paid.

contribution / student = net tuition / student − variable cost / student

4 · The step cost

Capacity comes in lumps. Fill a unit and the next student forces a whole new lump of cost — a discontinuity the tool is built to make visible.

Edition	Step trigger	Step cost
K–8	Enrollment reaches the room cap	A second teacher (a full salary)
High School	A core subject fills its sections	A new section (one teacher's prorated time)

5 · Retention, attrition & Total Contract Value (TCV)

Retention is the share of returning-eligible students who re-enroll. Attrition is the gap. The top of the ladder (Grade 12, or the exit room) graduates — that's completion, not attrition. The cost of a departing student is the rest of their contract:

# remaining years × net tuition, escalated by tuition growth seat TCV = Σ over remaining years y of [ net tuition × (1 + growth)^y ] attrition = enrolled × (1 − retention) TCV at risk = attrition × seat TCV of the next grade/room

★

An entry-grade student carries the largest TCV (the most years remaining); a graduating student carries one year. That's why early-grade retention protects so much more contract value than a single year of tuition suggests.

6 · Non-tuition revenue & tuition dependency

Most schools don't break even on tuition alone — the annual fund and a draw from the endowment close the gap. Tuition dependency measures how exposed you are: the higher the share of revenue from tuition, the more every surplus rides on enrollment.

total revenue = net tuition + non-tuition revenue tuition dependency = net tuition ÷ total revenue

7 · Allocation policy HS

How shared overhead and revenue get spread across departments, sections, and teachers is the one choice a department chair will argue about — so in the high school edition it's a visible, switchable setting (per-student / per-credit / per-section), never hidden logic. The grade lens deliberately never spreads revenue, because a student belongs to exactly one grade.

Formula reference

The complete calculation set, in one place. Section-by-section detail follows in the edition walkthroughs.

K–8 · per classroom

instructional min/yr = min/day × days/week × weeks # seed: 420 × 5 × 32 = 67,200 teachers = 2 if enrolled ≥ room cap, else 1 teacher cost = teacher salary × teachers allocated rent = total fixed cost ÷ number of cost centers total cost = teacher cost + rent + (enrolled × variable/student) cost / minute = total cost ÷ instructional min/yr revenue / min = tuition collected ÷ instructional min/yr margin = 1 − (cost/min ÷ revenue/min)

High School · per section

sections (per core, per grade) = ⌈ grade enrollment ÷ section target ⌉ section enrollment = grade enrollment ÷ sections teachers (per dept) = round( Σ dept section-minutes ÷ teaching min/week ) section cost = teacher loaded salary × (section minutes ÷ teacher's weekly minutes) # reconciles exactly: Σ a teacher's section costs = that teacher's salary; Σ all = payroll

Net Revenue (both editions)

gross (sticker) = Σ enrolled × sticker discount = gross − net tuition discount rate = discount ÷ gross # = 1 − net ratio; sector avg ≈ 18% (NBOA) cost to educate/student = total cost ÷ enrollment gap = cost to educate/student − net tuition/student discount headroom = (net ratio − floor ratio) × gross cost of one point = gross ÷ 100 # price elasticity (ε is negative) enrollment(Δ) = E₀ × (1 + ε·Δ) NTR(Δ) = enrollment(Δ) × net price/student × (1 + Δ) recruit cost = attrition × acquisition cost per new student

K–8 EDITION · CLASSROOM

K–8 · School Dashboard

The whole school rolled into one year of instructional time. Where you start a planning session and where you return to see the net effect of any change.

What you see

Net surplus / deficit	Total revenue minus total cost, after non-tuition revenue is counted.
Tuition collected	Net tuition across all rooms, against total cost.
Cost to educate	Full cost per student, split into variable and capacity.
Enrollment	Filled seats against total seats school-wide.
The minute-ledger bar	Teal fill = revenue per instructional minute; the pink map-pin marks break-even (cost per minute). Teal past the pin is surplus.
Business-unit table	Every room: enrollment, net ratio, tuition, variable, total cost, surplus, margin. Click a row to open it.
Retention & contract value	Student-body TCV, net tuition at risk, and this-year leakage, with the blended retention rate.

How it's calculated

surplus = (net tuition + non-tuition revenue) − (teacher cost + fixed cost + variable cost) break-even pin = average cost per minute across rooms

K–8 · Classrooms

Every classroom as its own P&L. A card per room; click any card to open the planning drawer where you edit the roster seat by seat and watch the math move live.

The card

Four figures per room — enrolled, contribution per student, retention, and TCV at risk — plus two flags: a soft-retention flag where a grade leaks students, and a near-break flag where the next enrollment triggers a second teacher.

The drawer — levers

each seat's tuition add / remove a seat this room's retention rate

The drawer — what it shows

The next "yes" — the marginal economics: a full-pay seat adds (sticker − variable); an aided seat adds (its tuition − variable); and how many seats remain before the second-teacher step.
Retention & contract value — expected attrition, the room's contract value, net tuition at risk, and the value a 5-point retention slip would put in play.
Cost build-up — teacher + rent + variable = total cost, then tuition, contribution over variable, and surplus.

How it's calculated

contribution / student = avg net tuition − variable/student next aided seat value = aided tuition − variable/student seats to 2nd teacher = room cap − enrolled room TCV at risk = enrolled × (1 − retention) × seat TCV of the next room

Because the roster is the single source of truth, a discounted seat you add in the drawer immediately moves the room's net ratio, the dashboard surplus, and every contract-value figure that depends on it.

K–8 · Net Revenue

The strategic capstone — where you decide where to focus energy, framed around net tuition revenue rather than headcount. Four modules.

① Net tuition revenue north-star

What you see

NTR and NTR per student.
Cost-to-educate gap — per-student cost minus net tuition (positive means tuition is priced below cost, the common case).
Tuition dependency — share of revenue from tuition.
Discount rate against the ~18% sector norm.

② Tuition discounting & aid leverage

net-tuition-ratio floor

A split bar shows every sticker dollar divided into net tuition kept and aid given back. Set a floor and the tool computes your discount headroom — the additional aid you can commit before the blended ratio drops below it — and the NTR cost of one point of discount.

discount headroom = (current net ratio − floor) × gross tuition cost of one point = gross tuition ÷ 100

③ Pricing power (elasticity)

price elasticitytest a price change

Set how price-sensitive your families are; the curve finds where NTR peaks. Inelastic demand means NTR keeps climbing as price rises (you have room); elastic means you're past the peak.

NTR(Δ) = [ E₀ × (1 + ε·Δ) ] × [ net price/student × (1 + Δ) ]

④ Where to focus

Every returning-eligible classroom plotted by retention risk (vertical) against contract value at risk (horizontal). The upper-right is the priority quadrant. A ranked list orders the rooms, and the retain-vs-recruit panel compares the acquisition cost of replacing leavers against the contract value retaining them protects.

★

In a PK–12 school this matrix behaves differently than in a high school: early-childhood rooms often top the priority list despite low attrition, because each departure forfeits a contract worth more than a decade of tuition.

K–8 · Board Report

A presentation-ready snapshot of the whole model, built for the room where the decisions actually get made. One action assembles the executive narrative, the headline KPIs, and the charts into a clean document you can print or save to PDF and hand to a finance committee — no re-keying, no separate deck.

The executive narrative

A written summary generated straight from the model: surplus or deficit and by how much, whether the school clears break-even, the net tuition ratio against the sector benchmark, retention and the contract value at risk, and the units doing the most — and least — to carry their cost. The prose is assembled from the same engine that drives every other screen, with branching for the cases that matter: surplus vs. deficit, above vs. below break-even, discounting above vs. below the norm, and the current top offenders.

★

The narrative is deterministic and auditable, not generative. Every sentence is a template with the model's own figures dropped in, so the words can never drift from the numbers and any claim traces back to a line in the model. The honest trade-off: it states what is true without speculating about why — it reports the deficit, it doesn't diagnose the cause. That is the right posture for a board document, where a defensible figure beats a confident guess.

What the report contains

KPI tiles — net surplus/deficit, net tuition, net tuition ratio, enrollment, cost to educate, and contract value at risk, read at a glance.
Charts — the where-the-money-goes breakdown, the break-even bar, and the revenue-vs-cost picture, rendered the same way they appear on screen.
The business-unit table — every classroom's contribution, reconciled to the school total.

Print & PDF export

print / save to PDF

Export is a true print-to-PDF. A dedicated print stylesheet reflows the report for paper — hiding the app chrome, fixing the page breaks, and switching to print-safe color — and the browser's own Save-as-PDF produces the file. It comes out as crisp, selectable text rather than a screenshot, and it needs no external library or network call. That choice keeps the output dependency-free and avoids the rasterization and CDN pitfalls of client-side PDF converters.

Because the report reads directly from the model's engine output, reconciliation is automatic. Change a roster seat or a scenario lever, re-open the report, and the narrative, the tiles, and the charts all move together. There is never a second set of numbers to keep in sync — the board sees exactly what the model says.

K–8 · Scenario Planning

Project the cohort ladder forward 3, 5, or 8 years. Structural moves apply now; rates compound annually. Nothing here changes your live plan.

Levers

retention rateincoming entry classtransfers / yr tuition increase / yrnet-ratio erosion salary inflationfixed-cost inflation

How the ladder flows

# each year: entry room = incoming class every other room = room below × retention + transfers spread across rooms above the entry top room graduates out tuition(y) = Σ enrolled × net/student × (1 + tuition growth)^y cost(y) = teacher × (1+sal inf)^y + fixed × (1+fixed inf)^y + variable surplus(y) = (tuition(y) + non-tuition) − cost(y)

Outputs include surplus today vs. in N years, attrition per year, net tuition at risk, a revenue-vs-cost trajectory chart, and a reconciling year-by-year table.

K–8 · School Assumptions

Set these once; they feed every classroom and every scenario.

Group	Levers
Tuition rates	Sticker price per division (lower / upper school).
Teaching & calendar	Average teacher salary; minutes/day, days/week, weeks (these set instructional minutes/year).
Per-student costs	Itemized variable cost: materials, technology, food/auxiliary, activities.
Non-tuition revenue	Itemized: annual fund, endowment draw, auxiliary programs, fees.
Fixed costs	Itemized pool spread across cost centers as each room's "rent."
Retention by grade	Each room's re-enrollment rate; the top room graduates.
Enrollment dynamics	Default retention, incoming class, transfers, tuition growth (for TCV).
Strategy	Price elasticity, net-ratio floor, acquisition cost, discount benchmark.

HIGH SCHOOL EDITION · SECTION

HS · School Dashboard

The section is the business unit; everything else is a way of looking at the same sections. The dashboard shows where the money goes and the whole-school break-even.

What you see

Net surplus / deficit	Tuition plus non-tuition, minus every cost line.
Teaching staff required	FTE the master schedule needs, with section count and payroll.
Co-curricular net cost	Athletics, clubs, and activities after fee recovery.
Cost per student	Total cost ÷ enrollment, against revenue per student.
Where the money goes	A stacked bar: academic core, electives, per-student variable, athletics, activities, overhead.
Revenue vs. total cost	One bar for the whole school; the pin is break-even.
Retention & contract value	Student-body TCV, net tuition at risk, and a column chart breaking the at-risk value into the future years it spans.

HS · Business Units

A lens switcher: the same section data grouped four ways. Each lens answers a different question.

Lens	Question it answers	How revenue is handled
By Grade	Which grades carry their cost?	No spreading — a student belongs to exactly one grade. The most defensible lens, and the home of retention.
By Department	What does each department contribute?	Credit-weighted share of tuition (allocation policy). Small programs read negative — true and political.
By Section	Where do merge/cut decisions live?	Cost per seat by section size; under-enrolled sections flagged. The operational layer.
By Teacher	How efficient is staffing?	Students-per-FTE — the high-school analog of class size.

The grade lens — how it's calculated

teaching cost = Σ (section cost × grade's share of that section) overhead = (overhead + direct dept) × grade students ÷ total students co-curricular = co-curric net × grade students ÷ total students variable = grade students × variable/student net revenue = net tuition + grade's per-student share of non-tuition surplus = net revenue − (teaching + overhead + co-curricular + variable)

Clicking a grade opens a drawer with the same "next yes" marginal economics, the editable per-grade retention with contract value at risk, a reconciling cost build-up, and the sections its students sit in. A grouped column chart shows net revenue vs. cost per grade.

The high-school "next yes" step cost is a new section, not a second teacher: a marginal student is accretive until they push a core subject past its section sizes, at which point the grade needs another section (one teacher's prorated time).

HS · Net Revenue

The same four-module strategy screen as the K–8 edition — NTR north-star, tuition discounting & aid leverage, pricing power (elasticity), and the where-to-focus matrix — but the focus matrix plots grades (9, 10, 11; Grade 12 graduates) rather than rooms.

All four modules are identical in method to the K–8 edition (see section 06). The differences are structural: TCV spans up to four years here rather than the K–8's full ladder, and the focus matrix has three returning-eligible grades, so the priority story is about 9th-grade fit and the senior-year exit rather than early-childhood contracts.

HS · Activities & Athletics

The co-curricular lever screen. These programs rarely pay for themselves; the question is how much subsidy is intentional.

Levers

activity fee recoverystipend level minimum elective sizecut / restore each program

How it's calculated

program gross = stipend × stipend level + program cost fees recovered = gross × fee recovery program net = gross − fees recovered cost / participant = program net ÷ participants # electives below the minimum size are flagged; one-click consolidation cuts them

Every cut or lever here flows straight to the dashboard, the grade lens, and your scenarios.

HS · Scenario Planning

Academic and co-curricular levers projected through the 9→12 cohort ladder.

Levers

retention rateincoming grade-9 classtransfers / yr tuition increase / yrstaff & cost inflation stipend inflationelective floorfee recovery

How the ladder flows

# each year: grade 9 = incoming class grade 10 = grade 9 × retention (and so on up) + transfers spread across grades 10–12 grade 12 graduates out cost(y) = payroll × (1+cost inf)^y × enroll multiplier + overhead × (1+cost inf)^y + co-curricular × (1+stipend inf)^y + variable surplus(y) = (tuition(y) + non-tuition) − cost(y)

Slider ranges scale from your Assumptions values — set a 300-student class in Assumptions and the scenario slider reaches it. Opening the scenario re-syncs the enrollment levers to your current assumptions, so a changed class size flows through.

HS · School Assumptions

Everything the lenses depend on, including the allocation policy that's deliberately exposed rather than hidden.

Group	Levers
Tuition & enrollment	Sticker tuition, net ratio, tuition growth, students per grade.
Staffing & schedule	Average loaded salary, teaching minutes/week, core section target.
Overhead & allocation	Overhead pool, direct department costs, and the per-student / per-credit / per-section policy switch.
Per-student costs	Itemized variable cost per student.
Non-tuition revenue	Itemized: annual fund, endowment draw, auxiliary, fees.
Enrollment dynamics & retention	Default retention, grade-9 class, transfers, and per-grade retention rates.
Strategy	Price elasticity, net-ratio floor, acquisition cost, discount benchmark.

Glossary

Net tuition revenue (NTR)	Tuition actually collected after aid and discounts. The metric EMA places at the center of enrollment strategy.
Net tuition ratio	Collected ÷ sticker. One minus the discount rate.
Discount rate	Aid and discounts ÷ sticker tuition. Sector average ≈ 18% (NBOA).
Contribution margin	Net tuition per student minus variable cost per student.
Capacity cost	Cost sunk on a unit whether or not it fills (teacher + allocated overhead).
Step cost	The lump of cost added when a unit fills — a 2nd teacher (K–8) or a new section (HS).
Total Contract Value (TCV)	A student's remaining enrolled years × annual net tuition, escalated by tuition growth.
TCV at risk	The remaining contract value this year's attrition forfeits.
Tuition dependency	Net tuition ÷ total revenue. Lower is more resilient.
Discount headroom	Additional aid that can be committed before the net ratio crosses a chosen floor.
Price elasticity (ε)	Percent change in enrollment per percent change in price. Established schools tend to be inelastic.
Allocation policy	The switchable rule for spreading shared overhead and revenue (per-student / per-credit / per-section).

Chalkline Field Guide · methodology reference for the K–8 and high school editions. Every figure in the tool is editable; seeded values are realistic stand-ins. This guide describes a planning model, not an accounting system.