How lease vs buy is worked out
Leasing and buying are priced on different things, so the fair comparison is the net cost over the same months. The lease gross is the drive-off fee plus the lease payment times the months. The buy gross is the down payment plus the buy payment times the months, plus the maintenance. The buy net is the buy gross minus the resale value, because the buyer keeps the car. The lease net is the lease gross, because the lessee hands the car back with nothing kept. The net winner is the smaller of the lease net and the buy net, and the gap between them is how much the winner wins by.
At the defaults — 36 months, lease $450.00/mo, drive-off $1,500.00, buy down $3,500.00, buy $620.00/mo, maintenance $1,200.00, resale $22,000.00 — the lease gross is $1,500.00 + 36 × $450.00 = $17,700.00, the buy gross is $3,500.00 + 36 × $620.00 + $1,200.00 = $27,020.00, and the buy net is $27,020.00 − $22,000.00 = $5,020.00 — so buying wins net by $17,700.00 − $5,020.00 = $12,680.00. Per month that is $17,700.00 ÷ 36 = $491.67/mo to lease against $5,020.00 ÷ 36 = $139.44/mo net to buy.
| Case | Lease gross | Buy gross | Buy net | Net winner |
|---|
| 36 mo, lease $450, buy $620 (default) | $17,700.00 | $27,020.00 | $5,020.00 | Buy by $12,680.00 |
| 48 mo | $23,100.00 | $34,460.00 | $12,460.00 | Buy by $10,640.00 |
| Lease $350/mo | $14,100.00 | $27,020.00 | $5,020.00 | Buy by $9,080.00 |
| Buy $750/mo | $17,700.00 | $31,700.00 | $9,700.00 | Buy by $8,000.00 |
| Resale $18,000 | $17,700.00 | $27,020.00 | $9,020.00 | Buy by $8,680.00 |
| Buy down $7,000 | $17,700.00 | $30,520.00 | $8,520.00 | Buy by $9,180.00 |
| 24 mo | $12,300.00 | $19,580.00 | -$2,420.00 | Buy by $14,720.00 |
The worked example, line by line
Setup: 36 months, lease $450.00/mo, drive-off $1,500.00, buy down $3,500.00, buy $620.00/mo, maintenance $1,200.00, resale $22,000.00.
Line 1 — the lease gross. $1,500.00 + 36 × $450.00 = $17,700.00.
Line 2 — the buy gross. $3,500.00 + 36 × $620.00 + $1,200.00 = $27,020.00.
Line 3 — the buy net. $27,020.00 − $22,000.00 = $5,020.00. The buyer keeps a car worth $22,000.00, so the net cost is the gross minus the resale.
Line 4 — the net winner. $17,700.00 − $5,020.00 = $12,680.00 to buying. Per month that is $491.67 to lease against $139.44 net to buy.
Line 5 — the upfront winner. $3,500.00 − $1,500.00 = $2,000.00 to the lease: the lease asks for $2,000.00 less on day one, even though it costs $12,680.00 more over 3 years.
Line 6 — the break-evens. Buying ties the lease if the resale value falls to $27,020.00 − $17,700.00 = $9,320.00, or if the buy payment rises to ($17,700.00 − $3,500.00 − $1,200.00 + $22,000.00) ÷ 36 = $972.22/mo.
Every branch, checked
48 months: the lease gross is $1,500.00 + 48 × $450.00 = $23,100.00, the buy gross is $3,500.00 + 48 × $620.00 + $1,200.00 = $34,460.00, and the buy net is $34,460.00 − $22,000.00 = $12,460.00 — so buying still wins net by $10,640.00. A longer term narrows the gap, because the lease keeps charging every month while the resale value stays put.
Lease $350/mo: the lease gross falls to $1,500.00 + 36 × $350.00 = $14,100.00, so buying wins net by $14,100.00 − $5,020.00 = $9,080.00. A cheaper lease narrows the gap a lot, but the resale value still carries buying.
Buy $750/mo: the buy gross rises to $3,500.00 + 36 × $750.00 + $1,200.00 = $31,700.00, so the buy net is $31,700.00 − $22,000.00 = $9,700.00 and buying wins by $8,000.00. A dearer loan narrows the gap, because every extra dollar of payment is a dollar of net cost.
Resale $18,000: the buy net rises to $27,020.00 − $18,000.00 = $9,020.00, so buying wins by $8,680.00. A car that holds its value badly is the lease’s best friend: every $1,000 of lost resale is $1,000 off buying’s advantage.
Buy down $7,000: the buy gross rises to $7,000.00 + 36 × $620.00 + $1,200.00 = $30,520.00, so the buy net is $30,520.00 − $22,000.00 = $8,520.00 and buying wins by $9,180.00. A bigger down payment costs more upfront and more net, because it is cash out of your pocket either way.
24 months: the lease gross is $1,500.00 + 24 × $450.00 = $12,300.00, the buy gross is $3,500.00 + 24 × $620.00 + $1,200.00 = $19,580.00, and the buy net is $19,580.00 − $22,000.00 = -$2,420.00 — a negative net, which means the buyer ends ahead: the car is worth $2,420.00 more than the buyer paid over 2 years. Buying wins net by $12,300.00 − (-$2,420.00) = $14,720.00.
Reverse — the break-evens: buying ties the lease if the resale value falls to $9,320.00, or if the buy payment rises to $972.22/mo. A resale value below $9,320.00, or a buy payment above $972.22 a month, flips the answer to leasing.
What the defaults assume
The model assumes the lease and the loan run the same months, the resale value is what the car actually sells for at the end, and the maintenance is the whole cost of keeping the car while you own it. It assumes the lease has no excess-mileage or damage charges at hand-back, and that the loan is paid off at the end of the term. It leaves out insurance, tax differences between leasing and buying, and the interest on the loan — the buy monthly payment is the whole payment, so a loan with a high rate needs a higher monthly figure. Rounding convention: money is rounded to cents, months are whole numbers, and all figures are computed from unrounded values, rounded only for display.
Output · formula · meaning
| Output | Formula | What it means |
|---|
| Lease gross | drive-off + lease monthly × months | $17,700.00. |
| Buy gross | down + buy monthly × months + maintenance | $27,020.00. |
| Buy net | buy gross − resale value | $5,020.00. |
| Net winner | lease gross − buy net | Buy wins by $12,680.00. |
| Lease net/mo | lease gross ÷ months | $491.67/mo. |
| Buy net/mo | buy net ÷ months | $139.44/mo. |
| 48 mo | same model, 48 months | Lease gross $23,100.00, buy net $12,460.00, buy wins by $10,640.00. |
| Lease $350/mo | same model, lease $350 | Lease gross $14,100.00, buy net $5,020.00, buy wins by $9,080.00. |
| Buy $750/mo | same model, buy $750 | Buy gross $31,700.00, buy net $9,700.00, buy wins by $8,000.00. |
| Resale $18,000 | same model, resale $18,000 | Buy net $9,020.00, buy wins by $8,680.00. |
| Buy down $7,000 | same model, down $7,000 | Buy gross $30,520.00, buy net $8,520.00, buy wins by $9,180.00. |
| 24 mo | same model, 24 months | Lease gross , buy gross , buy net , . |
| Reverse: break-even resale | buy gross − lease gross | $9,320.00. |
| Reverse: break-even buy payment | (lease gross − down − maintenance + resale) ÷ months | $972.22/mo. |
Who uses this
- The commuter choosing a new car: they learn buying wins by $12,680.00 over 3 years — $17,700.00 to lease against a $5,020.00 net cost to buy — so they know the lease is the dearer habit, and they know the lease still asks for $2,000.00 less upfront.
- The driver who swaps cars every 3 years: they learn the lease costs $491.67/mo against $139.44 a month net to buy, so they check whether the new-car-every-3-years habit is worth $12,680.00, or whether keeping the car longer is the cheaper habit.
- The buyer with a $7,000 deposit saved: they learn a $7,000 down payment leaves a buy net of $8,520.00 — still $9,180.00 ahead of the lease — so they know the bigger deposit does not change the answer, it just costs more upfront.
- The driver whose car holds its value badly: they learn buying ties the lease if the resale value falls to $9,320.00 — so they know a car that loses value fast is the one case where leasing wins, and they check the resale value before they decide.
Accuracy & limitations
The math is exact for the numbers you enter: the lease gross is the drive-off plus the monthly payment times the months, the buy gross is the down payment plus the monthly payment times the months plus the maintenance, and the buy net is the buy gross minus the resale value. What the model cannot do is predict your car’s resale value: check what the same car actually sells for at 3 years old, and use that number, not the dealer’s guess. It leaves out insurance, tax differences between leasing and buying, and excess-mileage or damage charges at lease hand-back — ask the dealer to put those in writing. It assumes the lease and the loan run the same months, and that the loan is paid off at the end of the term. For the cost of running the car day to day, see auto insurance cost calculator; for buying new against used, see buy new vs used car.
Cite this calculatorBright Side Kit. “Lease vs Buy a Car Calculator: 3-Year Cost in 2026.” brightoolbox.com, 2026. Method: lease gross = drive-off + lease monthly × months; buy gross = down + buy monthly × months + maintenance; buy net = buy gross − resale value; net winner = lease gross − buy net; break-even resale = buy gross − lease gross; break-even buy payment = (lease gross − down − maintenance + resale) ÷ months. Defaults: 36 mo, lease $450.00/mo, drive-off $1,500.00, buy down $3,500.00, buy $620.00/mo, maintenance $1,200.00, resale $22,000.00 → lease gross $17,700.00, buy gross $27,020.00, buy net $5,020.00, buy wins net by $12,680.00; 48 mo → lease gross $23,100.00, buy gross $34,460.00, buy net $12,460.00, buy wins by $10,640.00; lease $350/mo → lease gross $14,100.00, buy wins by $9,080.00; buy $750/mo → buy gross $31,700.00, buy net $9,700.00, buy wins by $8,000.00; resale $18,000 → buy net $9,020.00, buy wins by $8,680.00; buy down $7,000 → buy gross $30,520.00, buy net $8,520.00, buy wins by $9,180.00; 24 mo → lease gross $12,300.00, buy gross $19,580.00, buy net -$2,420.00, buy wins by $14,720.00; break-even resale $9,320.00; break-even buy payment $972.22/mo.Bright Side Kit. "Lease vs Buy a Car Calculator: 3-Year Cost in 2026." https://brightoolbox.com/lease-vs-buy-car-calculator/ Accessed October 24, 2026.
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