Burn rate and runway, the way an investor reads them

Published 2026-08-15 · updated 2026-08-15

Gross burn and net burn are not the same number

Gross burn is total cash going out in a month — payroll, rent, software, contractors, everything. Net burn is gross burn minus cash coming in from revenue in the same period. A company with $180,000 in monthly operating expense and $60,000 in monthly revenue has a gross burn of $180,000 and a net burn of $120,000, and an investor reading a deck wants both, because they answer different questions.

Gross burn is the cost structure question: what does it take to run this business at its current size, independent of whether it is selling anything. Net burn is the survival question: at the current pace of revenue and spend, how fast is cash actually declining. A board deck that reports only net burn hides the cost structure behind whatever revenue happened to land that month — and a founder trying to read their own numbers should want to see both lines separately for the same reason.

Runway is computed off net burn — on reconciled cash

Runway is cash on hand divided by average monthly net burn, expressed in months. The two places this breaks are the numerator and the denominator, and they break in opposite directions.

The numerator has to be reconciled cash, not the number showing on the bank app. A bank balance includes checks that have not cleared, ACH payments that are pending, and a payroll run that has been submitted but not yet debited. None of that is available cash — it is cash already committed. Runway computed off an unreconciled bank balance routinely overstates the real number, sometimes by a full payroll cycle, because the balance has not yet caught up with commitments the company has already made. The reconciliation is the same discipline as closing the books for the month: every account tied to its statement, every pending item identified as pending rather than counted as available.

The denominator has to be an average, not a single month, for the reason in the next section — one month of net burn is a volatile number to divide by, and a volatile denominator produces a runway figure that swings for reasons that have nothing to do with the trend an investor is actually asking about.

One-off items distort a single month badly

A single month of net burn is a noisy number even in a stable business, because expense and revenue timing rarely land evenly across a calendar month. A handful of items do most of the damage:

An annual software or insurance renewal that hits in one month instead of being spread across twelve
A large one-time contractor or legal invoice — a fundraise, a contract negotiation, a one-off compliance filing — landing in the period being measured
A customer prepayment or a multi-month invoice collected up front, which inflates that month's cash-in without representing a repeatable run rate
A payroll cycle that happens to include an extra pay period in a given month, common with biweekly payroll schedules where some months carry three pay runs instead of two
A large vendor payment pulled forward or pushed back by a few days across a month boundary, moving spend into a different month than the one it was actually incurred in

The three-month-average convention

The standard fix is averaging net burn over the trailing three months rather than reading the most recent month on its own. Three months is enough to smooth a single annual renewal or a shifted payroll cycle without also smoothing away a real change in trajectory — a genuine step-up in spend from a new hiring cohort, or a genuine improvement from a pricing change, still shows up within a trailing three-month window; it just does not swing the number on the strength of one invoice.

The convention only works if it is applied consistently and disclosed as what it is. A board deck that silently switches between single-month and trailing-average burn depending on which number looks better in a given period is a pattern diligence reviewers are specifically trained to catch, because it is one of the easier ways a number gets quietly managed. Pick trailing-three-month net burn, state that it is trailing-three-month net burn, and report it the same way every period — including the periods where it goes the wrong direction.

How deferred revenue and payroll timing fake a good month

Two mechanics produce a month that looks better than the underlying business actually is, and both are common enough that an investor's diligence team checks for them by default.

The first is a prepayment booked as revenue when it was collected rather than as it is earned. A customer who pays for a full year up front puts real cash in the bank in month one, but under accrual accounting only one-twelfth of that contract is revenue for that month — the rest sits in a deferred revenue liability and releases over the following eleven months. A cash-basis read of that month looks like a strong revenue month. It is not; it is a strong collections month, and the two are different facts. Net burn computed against cash received rather than revenue earned will understate the real burn rate in the month the prepayment lands, and overstate it in the months that follow once the cash cushion is gone but the deferred balance has not fully released.

The second is payroll timing. Biweekly payroll produces twenty-six pay periods a year, which does not divide evenly into twelve months — most months carry two pay runs, but two months a year carry three. A month with only two pay runs shows lower payroll expense than the company's actual run rate, purely because of where the calendar landed, not because headcount cost changed. Reading that month's net burn at face value and projecting it forward overstates runway until the three-pay-period month arrives and burn jumps for no reason the numbers explained in advance.

Both distortions are visible from the same fix: reconcile cash against the general ledger and read net burn off accrual-basis figures with deferred revenue and payroll accruals properly booked, not off the raw cash-in/cash-out difference for a single calendar month.

The monthly pack that makes the number defensible

A burn and runway figure that survives a diligence question is built from a small, consistent set of artifacts produced the same way every month, not assembled retroactively when an investor asks for it.

A reconciled cash balance for the period — every account tied to its statement, pending items flagged as pending rather than counted as available
Gross burn and net burn reported as two separate lines, not folded into one figure
Trailing-three-month average net burn alongside the single-month figure, both computed the same way every period
A one-line note on any month containing a known one-off — an annual renewal, a large one-time invoice, an extra pay period — so a reader does not have to guess why a month moved
The deferred revenue schedule and payroll tie-out feeding the accrual-basis figures, current as of the same close date as the cash reconciliation

Where this fits with the rest of the pack

Burn and runway are one output of a monthly close, not a separate calculation done off to the side. They depend on the same reconciled cash position, the same deferred revenue schedule, and the same payroll tie-out that feed the rest of a board or investor reporting pack — which is why a business with a clean monthly close can produce a defensible runway figure on request, and a business reconstructing its books at fundraise time usually cannot, no matter how good the underlying numbers actually are.

CapEasy's part in this is the mechanical layer: the monthly reconciliation, the deferred revenue and payroll schedules, and the burn and runway figures built from them in a consistent format each period. What a given month's burn implies about runway strategy, hiring pace, or the next raise is a conversation for you and your board — the pack is what makes that conversation start from numbers everyone can trust.

Reading about it is optional. The books aren’t.

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