marketing calculator

Marketing Burn Rate & CAC Runway Calculator

Simulate marketing runway, monthly burn, and total new customers acquirable from budget.

Quick actions: Save inputs, view saved runs, print, share, or export results

Saved Runs

Inputs

Total Marketing Budget$

Monthly Fixed Overhead$

Customer Acquisition Cost (CAC)$

Target New Customers / Month

Results

Marketing Runway

8.0 months

Total Monthly Burn$15,000

Total Acquirable Customers400

Variable CAC Cost/Month$10,000

Bookmark this marketing runway calculator

Marketing budgets, CAC, and acquisition targets change with every growth sprint. Bookmark this page to re-model your runway with updated inputs each quarter.

Formula

Marketing Runway Formula

Monthly Burn = Overhead + (Target Customers × CAC). Runway = Budget / Monthly Burn. Total Customers = Target × Runway.

Projects how many months your marketing budget sustains operations at your target acquisition pace and overhead level.

Step by step

How the calculation works

1Enter your total available marketing budget and monthly fixed overhead (team, tools, retainers).
2Set your customer acquisition cost (CAC) and monthly customer acquisition target.
3Runway shows how many months remain at the current burn rate.
4Reduce CAC or overhead to extend runway without cutting acquisition targets.

Related guides

Learn more about this calculation

Guide

Paid Media Metrics Guide: CPC, CPM, CTR, CPA, ROAS, and ROI in Plain English

Understand the paid media metrics that actually matter. Learn how CPC, CPM, CTR, CPA, ROAS, and ROI connect, when to use each one, and how to avoid reporting cheap traffic as business success.

Site Guide

How to Use Do The Calculation Calculators: A Practical Step-by-Step Guide

Learn the fastest reliable workflow for using Do The Calculation calculators, reading results, checking formulas, and using save, print, share, and export actions correctly.

How to understand and use this calculator

What is marketing runway?

Marketing runway measures how many months your current marketing budget will sustain operations at your target acquisition rate. Monthly Marketing Burn = Monthly Overhead + (Target New Customers × CAC). Runway (Months) = Total Marketing Budget ÷ Total Monthly Burn.

If you have $120,000 in marketing budget, $5,000 in monthly overhead (tools, team, agency retainers), a $200 CAC, and target 50 new customers/month: Variable CAC cost = 50 × $200 = $10,000. Total burn = $15,000/month. Runway = $120,000 / $15,000 = 8 months. Total acquirable customers = 50 × 8 = 400.

Marketing runway planning is especially critical for startups, seasonal businesses, and companies in growth mode where marketing spend is a significant percentage of total operating costs.

What components belong in marketing overhead?

Fixed overhead includes marketing team salaries and benefits, agency retainer fees, SaaS tool subscriptions (CRM, automation, analytics, design tools), event and conference budgets, and content production fixed costs.

Variable overhead (separate from per-customer CAC) includes campaign management fees, creative production costs that don't scale linearly with customers, and brand awareness spend that doesn't directly generate attributable conversions.

The distinction between overhead and CAC matters for runway modeling. CAC should only include costs directly attributable to acquiring a new customer — primarily performance marketing spend (paid media, outbound tools, lead gen platforms). Agency fees for brand campaigns belong in overhead.

Sensitivity analysis and budget scenarios

Runway models are most useful when run across multiple scenarios. Best case: CAC improves 20% through creative optimization. Base case: current CAC holds. Worst case: CAC increases 30% due to competition or audience saturation.

At a $200 CAC (base), $250 CAC (worst), and $160 CAC (best) with the same inputs, runway changes from 8 months (base) to 6.5 months (worst) to 9.5 months (best). This 3-month range should inform how aggressively you acquire customers early vs. conserving runway for learnings.

Pair runway analysis with Customer Acquisition Cost tracking and Customer Lifetime Value projections to validate that each month of runway investment creates compounding revenue from acquired customers that eventually funds future growth cycles.

Extending marketing runway

Lower your effective CAC without reducing acquisition volume by: improving landing page conversion rates (see landing page conversion calculator), optimizing ad targeting, improving email nurture sequences to accelerate lead-to-customer cycles.

Reduce overhead burn by auditing your marketing technology stack. Most companies use only 30–40% of the features they pay for. Consolidating on platforms with overlapping capabilities and renegotiating annual contract discounts can significantly reduce fixed overhead.

Revenue from newly acquired customers that comes back into the marketing budget (from positive unit economics) effectively extends runway. If LTV/CAC ratio is 3:1 and payback period is 6 months, customers acquired in Month 1 start funding Month 7+ customer acquisition.

Frequently Asked Questions

What is a healthy marketing runway for a startup?+

12–18 months of runway is commonly cited as a healthy buffer for startups. For marketing-specifically (as opposed to total operational runway), 6–12 months allows enough time to run experiments, identify winning channels, and scale before needing to fundraise or achieve revenue sustainability.

How does CAC payback period affect runway strategy?+

If your CAC payback period (time to recover CAC from customer revenue) is 6 months, you're deploying budget today that returns in 6 months. A shorter payback period means acquired customers re-fund your marketing faster, effectively extending functional runway.

Should I include only paid media in CAC for runway modeling?+

Use fully-loaded CAC (including people, tools, and overhead allocated to acquisition) for accurate runway modeling. However, for sensitivity analysis, also model with marketing-only CPC/CPA (just paid media cost) to isolate media efficiency from overhead.

What triggers a need to recalculate marketing runway?+

Recalculate when: CAC changes by >15%, you hire or lose marketing team members, you add or remove a significant paid channel, your target customer acquisition pace changes, or you receive new funding/revenue that adjusts the budget.

How do acquisition targets affect runway?+

Higher targets consume budget faster. Model the customer acquisition pace that maximizes the total customers acquired before budget depletes, not just the fastest possible pace. If reducing pace by 20% extends runway by 40%, you may acquire more total customers.

What is the difference between marketing runway and total company runway?+

Marketing runway models only marketing budget and marketing-related CAC spending. Total company runway includes all operational costs (R&D, sales, G&A, engineering). Marketing runway is a subset used specifically for growth planning.

Should I account for revenue from acquired customers in runway?+

Conservative runway models treat customer revenue separately from marketing budget (pure cash-in runway). Growth models may reinvest margin from acquired customers back into marketing spend, extending functional runway. Model both scenarios.

How does customer churn affect my effective marketing runway?+

High churn forces constant re-acquisition spending just to maintain the customer base. At 5% monthly churn, you lose half your customer base in ~14 months regardless of acquisition. Factor churn costs into your effective marketing burn rate.

What happens when runway falls below 3 months?+

With less than 3 months of runway, shift from growth-mode to efficiency-mode spending immediately: cut lowest-ROAS channels, reduce overhead, focus on organic and referral channels that have lower direct spend. Alert leadership for fundraising or revenue acceleration decisions.

Can I use runway to decide between two marketing channels?+

Yes. Model runway for a budget split between Channel A (high volume, high CAC) and Channel B (lower volume, lower CAC). The channel mix that maximizes total customers acquired within the budget period while maintaining 6+ months of runway is optimal.

What is blended CAC and when should I use it in runway modeling?+

Blended CAC includes all marketing spend divided by all new customers acquired, across all channels. Use blended CAC for runway at the company level. Use channel-specific CAC when optimizing within specific channel budgets.

How does the [marketing efficiency ratio (MER)](/calculators/mer-efficiency-ratio-calculator) relate to runway planning?+

MER (Total Revenue ÷ Total Marketing Spend) tells you the revenue multiple generated per marketing dollar. A MER of 4× means $1 of marketing generates $4 of revenue. High MER signals healthier unit economics, which improves the quality of each month of runway spent.

How the calculation works

1Enter your total available marketing budget and monthly fixed overhead (team, tools, retainers).

2Set your customer acquisition cost (CAC) and monthly customer acquisition target.

3Runway shows how many months remain at the current burn rate.

4Reduce CAC or overhead to extend runway without cutting acquisition targets.

How to understand and use this calculator

What is marketing runway?

Marketing runway planning is especially critical for startups, seasonal businesses, and companies in growth mode where marketing spend is a significant percentage of total operating costs.

What components belong in marketing overhead?

Sensitivity analysis and budget scenarios

Extending marketing runway

Frequently Asked Questions

What is a healthy marketing runway for a startup?+

How does CAC payback period affect runway strategy?+

Should I include only paid media in CAC for runway modeling?+

What triggers a need to recalculate marketing runway?+

How do acquisition targets affect runway?+

What is the difference between marketing runway and total company runway?+

Should I account for revenue from acquired customers in runway?+

How does customer churn affect my effective marketing runway?+

What happens when runway falls below 3 months?+

Can I use runway to decide between two marketing channels?+

What is blended CAC and when should I use it in runway modeling?+

How does the [marketing efficiency ratio (MER)](/calculators/mer-efficiency-ratio-calculator) relate to runway planning?+

Marketing Burn Rate & CAC Runway Calculator

Inputs

Results

Bookmark this marketing runway calculator

Marketing Runway Formula

How the calculation works

Learn more about this calculation

Paid Media Metrics Guide: CPC, CPM, CTR, CPA, ROAS, and ROI in Plain English

How to Use Do The Calculation Calculators: A Practical Step-by-Step Guide

Marketing Burn Rate & CAC Runway Calculator

Inputs

Results

Bookmark this marketing runway calculator

Key output metrics

Monthly Burn Breakdown

How to understand and use this calculator

What is marketing runway?

What components belong in marketing overhead?

Sensitivity analysis and budget scenarios

Extending marketing runway

Frequently Asked Questions

Marketing Runway Formula

How the calculation works

Learn more about this calculation

Paid Media Metrics Guide: CPC, CPM, CTR, CPA, ROAS, and ROI in Plain English

How to Use Do The Calculation Calculators: A Practical Step-by-Step Guide

Key output metrics

Monthly Burn Breakdown

How to understand and use this calculator

What is marketing runway?

What components belong in marketing overhead?

Sensitivity analysis and budget scenarios

Extending marketing runway

Frequently Asked Questions