Glossary

SaaS billing & metrics glossary

70 plain-English definitions of the metrics, billing mechanics, pricing models and revenue accounting terms that B2B subscription businesses actually run on — with the formula, an example, and why it matters operationally.

Metrics

20 terms

Annual recurring revenue (ARR)

The normalised value of a subscription business's recurring revenue over twelve months, excluding one-off charges such as implementation fees.

Average revenue per account (ARPA)

Recurring revenue divided by the number of active accounts — the average size of a customer relationship.

Bookings, billings and revenue

Three different numbers describing the same contract at three different moments — what was signed, what was invoiced, and what was earned....

Burn multiple

How many dollars of net cash a company burns to generate one dollar of net new ARR.

CAC payback period

The number of months of gross profit from a new customer required to repay what it cost to acquire them.

Cohort retention

Retention measured for a fixed group of customers grouped by when they started, tracked over their own lifetime rather than over calendar...

Committed annual recurring revenue (CARR)

ARR plus contracted revenue that has been signed but has not yet started billing.

Contraction revenue

Recurring revenue lost from customers who downgraded, removed seats or reduced usage commitments but did not cancel.

Customer acquisition cost (CAC)

The fully loaded sales and marketing cost of acquiring one new customer over a given period.

Customer lifetime value (LTV)

The total gross profit expected from a customer over the whole of their relationship with you.

Expansion revenue

Additional recurring revenue from existing customers — upsells, cross-sells, added seats, tier upgrades and usage growth.

Gross revenue retention (GRR)

The percentage of recurring revenue retained from an existing cohort after churn and downgrades, excluding any expansion — so it can never...

LTV:CAC ratio

The ratio of expected lifetime gross profit from a customer to the cost of acquiring them — a rough test of whether...

Logo churn

The percentage of customers — counted as accounts, not dollars — who cancel during a period.

Monthly recurring revenue (MRR)

Recurring subscription revenue normalised to a single month, regardless of how often the customer is actually invoiced.

Net revenue retention (NRR)

The percentage of recurring revenue retained from an existing cohort of customers over a period, including expansion and after churn and downgrades....

Revenue churn

The percentage of recurring revenue lost during a period through cancellations and downgrades.

Rule of 40

A benchmark stating that a SaaS company's revenue growth rate plus its profit margin should total at least 40%.

SaaS magic number

A measure of sales efficiency comparing new recurring revenue produced in a quarter against the sales and marketing spend of the prior...

SaaS quick ratio

The ratio of revenue gained to revenue lost in a period — a measure of how efficiently growth outpaces churn.

Billing

16 terms

Billing cycle

The recurring interval at which a subscription generates an invoice — monthly, quarterly, annually or on a custom period.

Billing in advance vs in arrears

Whether a customer is invoiced at the start of a service period for what they are about to receive, or at the...

Credit note

A document that reduces the amount a customer owes against a previously issued invoice — used for downgrades, corrections, refunds and goodwill...

Dunning

The automated process of recovering failed payments and overdue invoices through scheduled retries and customer communications.

Entitlement

The specific features, limits and access a customer is granted as a consequence of what they have purchased.

Invoice

The document requesting payment from a customer for a defined period or set of charges, and the legal and tax record of...

Involuntary churn

Customers lost because a payment failed rather than because they chose to leave — expired cards, insufficient funds, or unpaid invoices.

Merchant of record

The legal entity that sells to the end customer and carries responsibility for payment processing, tax collection and compliance on that sale....

Minimum commitment

A contractual floor on what a customer will spend over a period, regardless of how much they actually consume.

Overage

Charges for consumption beyond an included allowance or committed volume.

Prepaid credits

A model where customers buy a balance of credits up front and consumption draws it down until it is exhausted or expires....

Proration

Adjusting a subscription charge to reflect a change that happens partway through a billing period, so the customer pays only for what...

Tenant provisioning

Creating and configuring a customer's environment in a multi-tenant application when they sign up or change plan.

True-up

A retrospective adjustment that reconciles what a customer was billed against what they actually used or were entitled to.

Usage metering

Collecting and aggregating the consumption events that a usage-based charge is calculated from.

Usage-based billing

Charging customers according to how much they consume — API calls, seats active, data processed, messages sent — rather than a fixed...

Pricing

13 terms

Block pricing

Charging for usage in fixed-size blocks, where any consumption within a block costs the full block price.

Flat-rate pricing

Charging a single fixed recurring fee for access to the product, independent of usage or number of users.

Grandfathering

Allowing existing customers to remain on old pricing or packaging after it has been withdrawn for new customers.

Hybrid pricing

Combining more than one pricing mechanism in a single contract — typically a recurring platform fee plus usage, seats, or both.

Outcome-based pricing

Charging for results delivered — tickets resolved, leads qualified, cases closed — rather than for access, seats or consumption.

Per-seat pricing

Charging per user with access to the product, typically per month or per year.

Price book

A named set of prices for catalog items, used to price differently by region, currency, segment or partner without duplicating the catalog....

Price uplift

A contractual increase applied at renewal or on each anniversary of a multi-year contract, often tied to a fixed percentage or an...

Product catalog

The structured definition of everything you sell — products, plans, charges and rate structures — that quoting, billing and provisioning all read...

Ramp deal

A multi-year contract where the committed price or quantity increases on a defined schedule, typically stepping up each contract year.

Tiered pricing

A usage pricing structure where each band of units is charged at its own rate, so a single bill spans several rates...

Timed discount

A discount that applies only for a defined window of a subscription — the first three months, or the first year of...

Volume pricing

A usage pricing structure where the total quantity determines a single rate applied to every unit.

Sales & CPQ

10 terms

Approval workflow

Rules that route a quote for internal sign-off when it falls outside standard terms — deep discounts, non-standard payment terms, or unusual...

Auto-renewal

A contract term under which a subscription renews automatically for a further period unless the customer gives notice by a stated deadline....

CPQ (Configure, Price, Quote)

Software that assembles a valid product configuration, applies the correct pricing and discounts, and produces a quote a customer can sign.

Co-terming

Aligning the end dates of multiple subscriptions or add-ons so they renew together on a single date.

Multi-year contract

A subscription agreement covering more than one year, usually with committed pricing across the full term.

Order form

The signed commercial document that specifies what a customer is buying, at what price, on what terms — usually executed under a...

Product-led growth (PLG)

A go-to-market motion where the product itself drives acquisition, conversion and expansion, typically through free trials or a free tier with self-service...

Quote-to-cash

The end-to-end process from producing a quote through contract, subscription, invoicing, payment and revenue recognition.

Sales-led growth (SLG)

A go-to-market motion where deals are closed by a sales team through a managed process of demos, negotiation, quoting and contracting.

Self-service (customer portal)

Letting customers buy, upgrade, manage payment details and access invoices themselves, without contacting sales or support.

Revenue accounting

8 terms

RevOps

3 terms

Stop calculating this in a spreadsheet

Bunny computes SaaS metrics, revenue schedules and retention from your live billing data — because quoting, subscriptions, usage and invoicing all sit in one system.

FAQ

Frequently asked questions

What is this glossary?
A reference for the terms B2B SaaS revenue teams use every day — SaaS metrics such as ARR, NRR and the Rule of 40, billing mechanics such as proration, dunning and overage, pricing models such as tiered, volume and ramp deals, and revenue accounting concepts such as ASC 606, deferred revenue and performance obligations. Each entry gives the definition, the formula where one applies, and why it matters operationally.
What is the difference between ARR and MRR?
MRR is normalised recurring revenue for a single month. ARR is the annualised equivalent, usually MRR multiplied by twelve. Companies selling month-to-month self-service plans tend to report MRR; companies selling annual or multi-year B2B contracts tend to report ARR because their billing periods are annual.
What is the difference between NRR and GRR?
Gross revenue retention measures how much recurring revenue you keep from an existing cohort, counting churn and downgrades only — it is capped at 100%. Net revenue retention adds expansion from upsells, cross-sells and usage growth, so it can exceed 100%. GRR shows how leaky the bucket is; NRR shows whether the existing base grows on its own.
Why do these terms matter for billing systems?
Most of these definitions are only reportable if the underlying data lives in one place. If quotes sit in a CRM, subscriptions in a billing tool, and invoices in an accounting package, metrics such as NRR and schedules such as revenue recognition have to be reassembled by hand every month. When quoting, subscriptions, usage and invoicing share one system of record, they are computed rather than reconstructed.