Burn Rate Calculator for SaaS Founders

SaaS burn rate has unique dynamics. Recurring revenue means every customer you keep extends runway permanently. Every customer you lose shortens it. Standard burn calculations miss this — here is how to think about burn the SaaS way.

Why SaaS burn is different

In a non-recurring business, last month's sale does not help next month. A consultancy that booked $50K of projects in March needs to book another $50K in April. The runway calculation assumes constant revenue (or constant decline).

SaaS is the opposite. A customer who signed up last month is (hopefully) paying again this month, and next month, and the month after. Each new MRR dollar is a permanent reduction in your net burn — until they churn.

The SaaS burn formula

The basic formula is the same — net burn equals expenses minus revenue. But for SaaS, "revenue" should specifically be Monthly Recurring Revenue (MRR), not one-time payments.

Component	SaaS treatment
MRR	Sum of all active subscription payments this month
One-time revenue	Setup fees, training fees — separate, not MRR
Net burn	Expenses − MRR (ignore one-time for runway calc)
Runway	Bank ÷ Net burn (assuming MRR stays flat)

Why exclude one-time revenue? Because it does not repeat. Including it inflates your runway estimate by a number you cannot count on next month.

SaaS burn benchmarks by ARR stage

ARR	Typical net burn	Burn multiple target
$0-$100K	$15K-$50K/mo	N/A (pre-traction)
$100K-$1M	$40K-$150K/mo	Under 2
$1M-$5M	$150K-$400K/mo	Under 1.5
$5M-$20M	$400K-$1M/mo	Under 1.2
$20M+	$800K-$2M/mo	Under 1

The general rule: as you scale, your burn multiple should improve (drop). Investors get nervous when you scale ARR but burn multiple gets worse — it usually means CAC is climbing faster than LTV.

The MRR-to-burn relationship

Here is a worked example showing how MRR growth changes runway dramatically:

MRR	Monthly expenses	Net burn	Bank: $500K	Runway
$0	$80K	$80K	—	6.3 months
$15K	$80K	$65K	—	7.7 months
$30K	$80K	$50K	—	10 months
$50K	$80K	$30K	—	16.7 months
$80K	$80K	$0	—	Infinite (breakeven)

Same expenses across the board. Adding MRR transforms the runway picture. A SaaS that grows MRR by $15K/month over a few quarters can move from "scary runway" to "comfortable" without a fundraise.

The churn factor

Churn is the silent runway killer. If you add $20K of new MRR but lose $8K to churn, your net new MRR is only $12K. The burn calculation should always use net new MRR (gross adds minus churn).

Imagine two SaaS companies both adding $25K of gross new MRR each month:

• Low-churn (2%): On $200K MRR, churn is $4K/month. Net new = $21K/month. Runway extends quickly.
• High-churn (8%): On $200K MRR, churn is $16K/month. Net new = $9K/month. Runway barely improves.

Same sales effort, very different cash trajectory.

Actions specific to SaaS founders

1. Track net new MRR weekly, not just total MRR. The change is the runway signal.
2. Optimize for retention, not just acquisition. Reducing monthly churn from 5% to 3% is worth more than adding 2% to growth.
3. Watch payback period. If it takes 18 months for a customer to repay your CAC, your burn multiple will look bad even with great gross retention.
4. Annual contracts. Annual prepay customers give you the cash upfront and lower effective churn.
5. Update runway monthly with current MRR. Use the burn rate calculator with MRR as your "monthly revenue" input.

The compounding effect of SaaS burn discipline

Cutting $5K of monthly burn at a SaaS company is good. Adding $5K of MRR is mathematically equivalent for this month — but better for next month, and the month after, and next year. Spend your founder energy on retention and acquisition first, cuts second. The math will reward you.