Getting investor-ready

The startup metrics investors care about (MRR, burn, runway, CAC)

Updated 2 June 20265 min readLedgers Team

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MRR — monthly recurring revenue
Burn — how fast you spend
Runway — how long you've got
CAC — customer acquisition cost
The supporting cast
The thing that matters more than any single metric
How Ledgers keeps your metrics current and true

Getting investor-ready3 of 5

1.Get your startup financials investor-ready in a weekend
2.How to build a data room for your raise (the lean version)
3.The startup metrics investors care about (MRR, burn, runway, CAC)
4.What investors actually want to see before they invest
5.What is a cap table and how do I keep mine clean?

Quick answer

A plain-English guide to the startup metrics investors actually want — MRR, burn, runway, CAC and more — what each means, why it matters, and how to keep them current.

At some point in a fundraise, an investor will fire a handful of three-letter abbreviations at you and watch your face. MRR? Burn? Runway? CAC? It can feel like a test in a language you never learned.

Here's the reassuring truth: there are only a few metrics investors actually care about at pre-seed and seed, each one means something simple, and you already half-know them from running your business. The test isn't whether you can recite textbook definitions. It's whether you know your numbers, cold, and whether they're current.

Let's go through the ones that matter — what each means in plain English, why investors ask, and what a good answer looks like.

MRR — monthly recurring revenue

What it means. MRR is the predictable subscription income you bank every month. If you have 50 customers each paying £40 a month, your MRR is £2,000. (If you don't run subscriptions, the equivalent is just your monthly revenue.)

Why investors ask. Recurring revenue is the holy grail because it's predictable — they can see it compounding. But they care less about the number than the trend: is MRR growing month on month, and how fast? A small MRR growing 15% a month is far more exciting than a bigger one that's flat.

A good answer. "We're at £6k MRR, growing about 12% month on month for the last six months." Specific, trended, confident.

Burn — how fast you spend

What it means. Your burn is how much cash you're spending each month, net of what's coming in. Spend £20k, bring in £6k, and you're burning £14k a month. It's the speed at which your bank balance is shrinking.

Why investors ask. Burn tells them how disciplined you are and how long their money will last. A high burn isn't automatically bad — but it has to be explainable. Investors want to see you spending deliberately, not haemorrhaging cash on things you can't justify.

A good answer. "We're burning around £14k a month, mostly engineering salaries. We've kept it flat for two quarters while revenue grew."

Runway — how long you've got

What it means. Runway is how many months of cash you have left at your current burn. Cash of £140k, burn of £14k a month, equals 10 months of runway. It's the single most important survival number in your business. What is runway and how do I work out mine? →

Why investors ask. Runway tells them how urgent your raise is and whether you're raising from strength or desperation. It also tells them whether their money will get you far enough to hit the milestones that unlock the next round.

A good answer. "We've got about 10 months of runway. This raise extends that to 24 and gets us to £30k MRR." Notice how runway, burn and the plan all connect.

CAC — customer acquisition cost

What it means. CAC is what it costs you, on average, to win one customer. Spend £2,000 on marketing and sales in a month and win 20 customers, and your CAC is £100.

Why investors ask. CAC tells them whether your growth is economic. If it costs £100 to win a customer who pays you £40 a month and stays a year, that's a great machine. If they only stay two months, you're losing money on every sale. Investors are checking whether more money would buy profitable growth or just expensive growth.

A good answer. Pair it with what a customer is worth: "CAC is about £100, and a customer pays us roughly £480 a year, so the economics work and improve as we scale."

The supporting cast

A few more you'll hear, briefly:

Gross margin — what's left of each pound of revenue after the direct costs of delivering it. High margins (typical of software) mean the business gets very profitable at scale. What is gross margin and why should I care? →

Churn — the percentage of customers who leave each month. Low churn means what you've built is sticky; high churn quietly undoes all your growth.

LTV — lifetime value, the total a customer pays you before they leave. Investors love to see LTV comfortably bigger than CAC.

You don't need all of these polished for a seed round. But MRR, burn and runway are non-negotiable — know those three cold.

The thing that matters more than any single metric

Here's what founders miss. Investors aren't only checking the values of these metrics. They're checking whether you know them without looking, whether they're current, and whether they're true.

A founder who answers the runway question instantly, with a number that ties to their actual bank balance, signals control. A founder who says "let me check and get back to you," then sends a figure that doesn't match the financials in the data room, signals risk — no matter how good the underlying numbers are. The metric is the message, but so is the way you know it. What investors actually want to see before they invest →

The problem is that keeping these current by hand is genuinely hard. MRR lives in your payment processor, burn lives across a card and a bank feed, runway needs both plus your cash balance, CAC needs your spend and your customer count. Stitch those together manually and they're out of date the moment you finish — and the version in your head rarely matches the version in your books.

How Ledgers keeps your metrics current and true

In Ledgers, your investor metrics aren't a spreadsheet you maintain — they're a live read-out of your reconciled books.

Because your bank feeds in and reconciles continuously, your runway and burn are always current — no recalculation, no stale figures. (There's even a public runway calculator to sanity-check the maths.) Your revenue, growth and key metrics sit on one investor dashboard, updating as money moves, each tied to a reconciled ledger so the numbers are provably true. When an investor asks "can I see your latest numbers?", the Investor Room shows them a live, scoped view — including what's changed since they last looked — straight from those metrics. And your self-writing monthly update pulls the same figures in automatically, so you're never hunting for them the night before.

You walk into every investor conversation knowing your metrics cold — because they've been current and correct the whole time.

Ready to know your numbers cold? In Ledgers, your MRR, burn and runway are always current and reconciled, on one investor dashboard — and the Investor Room shares them live the moment an investor asks. See your numbers without learning accounting → start free.

Next, see the full picture investors check: What investors actually want to see before they invest →

And get the books behind the metrics ready: Get your startup financials investor-ready in a weekend →

Frequently asked questions

What metrics do investors look at in a startup?

At pre-seed and seed, the core ones are MRR (monthly recurring revenue), burn (monthly cash spend), runway (months of cash left) and CAC (cost to win a customer), plus supporting metrics like gross margin, churn and LTV. They care most about the *trend* and whether you know the numbers cold.

What's the difference between burn and runway?

Burn is how much cash you spend per month; runway is how many months of cash you have left at that burn rate. Cash divided by burn equals runway. Burn measures speed; runway measures survival time.

What is a good CAC for a startup?

There's no universal number — what matters is CAC relative to what a customer is worth over their lifetime (LTV). A common rule of thumb is LTV at least three times CAC. Investors want to see that spending more would buy profitable growth.

How current do my metrics need to be for investors?

As current as possible — ideally today's numbers. Investors trust founders whose metrics tie to their actual, recent bank balance and financials. Continuously reconciled books keep MRR, burn and runway current automatically.

See your numbers without learning accounting

Ledgers does the bookkeeping — bank feeds, VAT, year-end — and keeps your accountant in the loop. Free for pre-revenue founders.

Start free →

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