What inputs does the MRR / ARR Growth Calculator need?

It takes 5 inputs: currentMrr, netNewMrrPerMonth, monthlyChurnPercent, expansionMrrPerMonth (default 0), targetArr. Outputs returned: projectedMrr, ndr, monthsToTargetArr.

Can I verify the MRR / ARR Growth Calculator with a worked example?

Yes. With currentMrr = $10,000, netNew = $2,000, churn = 4%, expansion = $500, targetArr = $500,000. the tool returns mrr_12 ≈ $25,500, ndr ≈ 100.5%, monthsToTargetArr ≈ 22.

Where does the MRR / ARR Growth Calculator get its benchmark data?

Reference data is sourced from: OpenView SaaS Benchmarks 2024 (NDR percentiles) (as of 2024).

What can the MRR / ARR Growth Calculator not tell me?

Known limitations: Constant-growth past year one is rarely accurate. Segment by stage. Expansion revenue mechanics (seat growth, tier upgrades) are bundled into a single input.

Methodology: MRR / ARR Growth Calculator

1. Scope

Projects MRR/ARR at 3/6/12 months, Net Revenue Retention, and months to a target ARR. Deterministic compounding; does not model revenue risk distributions.

2. Inputs and outputs

Inputs

currentMrr number (currency)
netNewMrrPerMonth number (currency)
monthlyChurnPercent percent
expansionMrrPerMonth number (currency) default: 0
targetArr number (currency)

Outputs

projectedMrr

MRR at 3, 6, 12 months.
ndr

(starting MRR − churned + expansion) / starting MRR.
monthsToTargetArr

Solve for m such that mrr_m × 12 ≥ targetArr.

Engine source: src/lib/mrr-arr-growth-calculator/engine.ts

3. Formula / scoring logic

mrr_m = mrr_{m-1} + net_new - (mrr_{m-1} * churn) + expansion
ndr   = (starting_mrr - churned + expansion) / starting_mrr

4. Assumptions

Net-new and expansion MRR are constant. Most businesses see ramp and plateau rather than constant growth.
Churn is applied to current MRR each month.

5. Data sources

OpenView SaaS Benchmarks 2024 (NDR percentiles) as of 2024

6. Known limitations

Constant-growth past year one is rarely accurate. Segment by stage.
Expansion revenue mechanics (seat growth, tier upgrades) are bundled into a single input.

7. Reproducibility

Input
currentMrr = $10,000, netNew = $2,000, churn = 4%, expansion = $500, targetArr = $500,000.

Expected output
mrr_12 ≈ $25,500, ndr ≈ 100.5%, monthsToTargetArr ≈ 22.

8. Change log

2026-04-24 methodology page first published.

Worked example

Run live against the same engine this site ships (/engines/mrr-arr-growth-calculator.js). The inputs and outputs below are recomputed on every build and independently re-verified in CI — they are never hand-authored.

Input

tool: mrr_arr_growth_calculator
current_mrr: 25000
arpu: 99
new_subscribers_per_month: 50
churn_rate_percent: 3
expansion_mrr_per_month: 500
projection_months: 12
target_arr: 500000

Output

currentMrr: 25000
currentArr: 300000
projectedMrr3m: 38681.23
projectedMrr6m: 51167.72
projectedMrr12m: 72964.7
projectedArr12m: 875576.4
netRevenueRetention: 88.64
monthsToTargetArr: 4
projectionPoints[0].month: 1
projectionPoints[0].mrr: 29700
projectionPoints[0].arr: 356400
projectionPoints[1].month: 2
projectionPoints[1].mrr: 34259
projectionPoints[1].arr: 411108
projectionPoints[2].month: 3
projectionPoints[2].mrr: 38681.23
projectionPoints[2].arr: 464174.76
projectionPoints[3].month: 4
projectionPoints[3].mrr: 42970.79
projectionPoints[3].arr: 515649.48
projectionPoints[4].month: 5
projectionPoints[4].mrr: 47131.67
projectionPoints[4].arr: 565580.04
projectionPoints[5].month: 6
projectionPoints[5].mrr: 51167.72
projectionPoints[5].arr: 614012.64
projectionPoints[6].month: 7
projectionPoints[6].mrr: 55082.69
projectionPoints[6].arr: 660992.28
projectionPoints[7].month: 8
projectionPoints[7].mrr: 58880.21
projectionPoints[7].arr: 706562.52
projectionPoints[8].month: 9
projectionPoints[8].mrr: 62563.8
projectionPoints[8].arr: 750765.6
projectionPoints[9].month: 10
projectionPoints[9].mrr: 66136.89
projectionPoints[9].arr: 793642.68
projectionPoints[10].month: 11
projectionPoints[10].mrr: 69602.78
projectionPoints[10].arr: 835233.36
projectionPoints[11].month: 12
projectionPoints[11].mrr: 72964.7
projectionPoints[11].arr: 875576.4
growthRate3m: 54.7
growthRate12m: 191.9

Frequently asked questions

What does the MRR / ARR Growth Calculator calculate?: Projects MRR/ARR at 3/6/12 months, Net Revenue Retention, and months to a target ARR. Deterministic compounding; does not model revenue risk distributions.
What inputs does the MRR / ARR Growth Calculator need?: It takes 5 inputs: currentMrr, netNewMrrPerMonth, monthlyChurnPercent, expansionMrrPerMonth (default 0), targetArr. Outputs returned: projectedMrr, ndr, monthsToTargetArr.
What formula does the MRR / ARR Growth Calculator use?: The exact computation is: mrr_m = mrr_{m-1} + net_new - (mrr_{m-1} * churn) + expansion; ndr = (starting_mrr - churned + expansion) / starting_mrr
Can I verify the MRR / ARR Growth Calculator with a worked example?: Yes. With currentMrr = $10,000, netNew = $2,000, churn = 4%, expansion = $500, targetArr = $500,000. the tool returns mrr_12 ≈ $25,500, ndr ≈ 100.5%, monthsToTargetArr ≈ 22.
Where does the MRR / ARR Growth Calculator get its benchmark data?: Reference data is sourced from: OpenView SaaS Benchmarks 2024 (NDR percentiles) (as of 2024).
What can the MRR / ARR Growth Calculator not tell me?: Known limitations: Constant-growth past year one is rarely accurate. Segment by stage. Expansion revenue mechanics (seat growth, tier upgrades) are bundled into a single input.