面向订阅业务的 SaaS 指标计算器与仪表盘构建工具,可计算 MRR、ARR、流失率、NRR/GRR、LTV、CAC、CAC 回收期、魔数等。
Calculate every critical SaaS metric from raw subscription data and produce an investor-ready health snapshot. This skill guides Sam Ledger through computing MRR/ARR, churn, retention, unit economics (LTV/CAC), growth efficiency, and Rule of 40 scoring — then formats the output for board decks, investor updates, or feeding into kpi-alert-system threshold monitoring.
Trigger phrases:
Fits between:
startup-financial-model — feeds historical actuals into the 3-statement modelkpi-alert-system — outputs threshold-ready metric values for alert monitoringinvestor-memo-generator — supplies the metrics section of investor memosNOT for:
revenue-recognition-agent)qbo-automation)MetricFormulaBenchmarkMRRSum of all monthly recurring charges—ARRMRR × 12—New MRRMRR from new customers this period—Expansion MRRUpsells + seat adds from existing customers—Churned MRRMRR lost from cancellations—Contraction MRRDowngrades from existing customers—Net New MRRNew + Expansion − Churned − ContractionPositive = growing
MetricFormulaBenchmarkLogo ChurnCustomers churned / Customers at start<5%/yr for SMB, <2% enterpriseRevenue Churn (GRR)Churned+Contraction MRR / MRR at start>80% GRR goodNet Revenue Retention (NRR)(Start MRR + Expansion − Churn − Contraction) / Start MRR>110% excellent, >100% goodQuick Ratio(New + Expansion) / (Churned + Contraction)>4 = excellent, >2 = healthy
MetricFormulaBenchmarkLTVARPU / Monthly Churn Rate3× CAC minimumCAC(S&M Spend) / New Customers—LTV:CACLTV / CAC>3:1 healthy, >5:1 strongCAC PaybackCAC / (ARPU × Gross Margin%)<12mo excellent, <18mo goodMagic NumberNet New ARR / Prior Quarter S&M Spend>1.5 = efficient
MetricFormulaBenchmarkMoM Growth(MRR This Mo − Prior Mo) / Prior MoTop decile: 15%+ early stageRule of 40ARR Growth Rate % + FCF Margin %≥40 = healthyBurn MultipleNet Burn / Net New ARR<1 = excellent, <2 = good
Minimum viable inputs:
text
Period: [month/quarter]
MRR at start of period: $___
New MRR: $___
Expansion MRR: $___
Churned MRR: $___
Contraction MRR: $___
New customers acquired: ___
Customers churned: ___
Total customers at start: ___
S&M spend (period): $___
Gross margin %: ___
ARR growth rate (YoY %): ___
FCF or operating cash flow: $___
Optional (for deeper analysis):
text
Cohort data (monthly signup + retention by cohort)
Plan-level MRR breakdown
Customer segment breakdown (SMB / Mid-Market / Enterprise)
NPS or CSAT scores
python
net_new_mrr = new_mrr + expansion_mrr - churned_mrr - contraction_mrr
arr = (mrr_start + net_new_mrr) * 12
python
logo_churn = customers_churned / customers_start
grr = 1 - ((churned_mrr + contraction_mrr) / mrr_start)
nrr = (mrr_start + expansion_mrr - churned_mrr - contraction_mrr) / mrr_start
quick_ratio = (new_mrr + expansion_mrr) / (churned_mrr + contraction_mrr)
python
arpu = (mrr_start + net_new_mrr) / (customers_start + new_customers - customers_churned)
ltv = arpu / (logo_churn / 12) # annualized to monthly churn
cac = sm_spend / new_customers
ltv_cac = ltv / cac
cac_payback_months = cac / (arpu * gross_margin)
magic_number = (net_new_arr) / prior_sm_spend
python
rule_of_40 = arr_growth_pct + fcf_margin_pct
burn_multiple = abs(net_burn) / net_new_arr # only if burning cash
Apply benchmark thresholds and assign health grades:
text
═══════════════════════════════════════
SAAS METRICS SNAPSHOT — [Period]
Company: [Name] | As of: [Date]
═══════════════════════════════════════
REVENUE
MRR: $___,___
ARR: $___,___
Net New MRR: $___,___ (New: $X | Exp: $X | Churn: -$X)
MoM Growth: X.X% [🟢/🟡/🔴]
RETENTION
NRR: XXX% [🟢/🟡/🔴] (benchmark: >110%)
GRR: XX% [🟢/🟡/🔴] (benchmark: >80%)
Logo Churn: X.X% [🟢/🟡/🔴] (benchmark: <5%/yr)
Quick Ratio: X.X [🟢/🟡/🔴] (benchmark: >2)
UNIT ECONOMICS
LTV:CAC: X.Xx [🟢/🟡/🔴] (benchmark: >3:1)
CAC Payback: XX mo [🟢/🟡/🔴] (benchmark: <18mo)
Magic Number: X.X [🟢/🟡/🔴] (benchmark: >1.5)
EFFICIENCY
Rule of 40: XX [🟢/🟡/🔴] (benchmark: ≥40)
Burn Multiple: X.X [🟢/🟡/🔴] (benchmark: <2)
OVERALL HEALTH: 🟢 Strong / 🟡 Watch / 🔴 At Risk
TOP RISKS: [1-3 specific metrics to address]
When feeding downstream systems, output as:
json
{
"period": "2026-Q1",
"mrr": 125000,
"arr": 1500000,
"nrr": 118,
"grr": 87,
"logo_churn_annual": 4.2,
"quick_ratio": 3.1,
"ltv_cac": 4.5,
"cac_payback_months": 11,
"magic_number": 1.8,
"rule_of_40": 52,
"burn_multiple": 0.9
}
When cohort data is available, build a retention table:
text
Cohort Mo1 Mo2 Mo3 Mo6 Mo12
Jan-25 100% 89% 82% 74% 68%
Feb-25 100% 91% 85% 77% —
Mar-25 100% 88% 81% — —
Key outputs:
StageARRNRR TargetLogo ChurnRule of 40Pre-Seed<$1M>100%<10%N/ASeed$1-5M>105%<8%Growth-drivenSeries A$5-20M>110%<5%≥20Series B+$20M+>120%<3%≥40
SegmentNRR TargetLogo ChurnCAC PaybackSMB>100%<10%/yr<6 monthsMid-Market>110%<5%/yr<12 monthsEnterprise>120%<2%/yr<18 months
Pass current-period actuals as seed inputs for the 3-statement model:
Register thresholds for automated alerts:
text
NRR < 100% → CRITICAL alert (negative net expansion)
Logo churn > 7% → WARNING alert (annualized)
Quick ratio < 2 → WARNING alert
LTV:CAC < 3 → WARNING alert
Rule of 40 < 30 → INFO alert
Feed the snapshot JSON into the metrics section of investor memos. Include MoM/QoQ trends, not just point-in-time values.
Input: "Our MRR is $125K. We added $18K new, $12K expansion, lost $8K churn, $3K contraction. 210 customers, lost 7. Spent $45K on S&M. 75% gross margin. YoY growth 85%. Burning $80K/mo."
Output: Full snapshot with grades, flagging Rule of 40 and burn multiple.
Input: "Prepare Q1 2026 SaaS metrics for our Series A data room" Output: Formatted snapshot + cohort table + segment breakdown + narrative summary with investor framing.
Input: "Give me the 6 most important metrics for our board deck" Output: MRR/ARR, NRR, Logo Churn, LTV:CAC, CAC Payback, Rule of 40 — each with prior period comparison and trend indicator.
Always flag proactively:
Precision. Integrity. Results. — PrecisionLedger