A grant's burn ratio is the percent of the budget spent divided by the percent of the award period elapsed: 40% spent after 50% of the time is 0.8, spending slower than plan. The runway then tells you whether the money lasts once commitments are counted.
The numbers below are an example (a three-year award). Replace them with yours.
Salaries to the end of appointments, open orders, invoices due.
Apart from what is already committed: supplies, travel, services.
Spending slower than plan
A burn ratio well under 1 can mean delayed hires or orders. Check what the underspend is waiting for before treating it as free money: commitments are already counted in the runway.
Percent spent = spent to date / total budget Percent of time elapsed = months elapsed / months in award period Burn ratio = percent spent / percent of time elapsed Planned monthly burn = total budget / months in award period Actual monthly burn = spent to date / months elapsed Available = total budget - spent to date - committed Months of runway = available / expected monthly spend from now on Run-out date = today + months of runway
A three-year award of 750,000 with 18 months gone and 300,000 spent has a burn ratio of 0.40 / 0.50 = 0.8. With 260,000 committed, 190,000 is available. At an expected 9,500 a month from now on, the runway is 190,000 / 9,500 = 20 months, against 18 months left in the award: room for about two extra months of supplies, not the large surplus the percentage suggested. These are the numbers the calculator starts with.
It works on totals. A real grant has budget lines (personnel, equipment, travel) with their own rules and rebudgeting limits, and a sponsor’s financial system is the record. Use this to see the shape of the whole grant; keep the line detail in your institution’s grants system or a spreadsheet. Nothing you type here is saved or sent anywhere.
A grant burn rate is how fast a grant is being spent compared with how fast time is passing. The quick check is the percent of the budget spent against the percent of the award period elapsed. Divide the first by the second to get the burn ratio: 1.0 is on plan, above 1 is spending faster than plan and below 1 is slower.
Percent spent is spent to date divided by the total budget. Percent of time is months elapsed divided by months in the award. Burn ratio is percent spent divided by percent of time. The monthly burn is spent to date divided by months elapsed, to compare with the planned monthly burn, which is the total budget divided by the months in the award.
Subtract what is spent and what is committed from the total to get the money available, then divide by the spending you expect each month from now on. That is the runway in months; add it to today's date for the run-out date. Use the expected spend from now, not the average so far, because a hire or an order changes the pace.
Money you have promised but not yet spent: salaries through the end of their appointments, open purchase orders and a subcontract invoice due next quarter. Leaving commitments out is the most common reason a grant that looked healthy runs out early.
Not always, but check why. Underspending can come from a delayed hire or order that will land later and push the burn rate up, or from a milestone that slipped. Treat the surplus as spendable only after the commitments are counted.