★ MONEY · CARS · AFFORDABILITY
Under budget by $299.98 a month — max car price $45,331.51. $5,000 take-home, 15% rule, $5,000 down, $2,000 trade-in, 60 months at 6.5% APR. Enter your numbers to work out yours.
Start with the monthly payment, not the sticker price. This calculator turns your take-home pay into a max monthly payment, a max loan, and a max car price — and checks the car you are eyeing against that budget.
Start with the monthly payment, not the sticker price. The rule of thumb is 15% of your monthly take-home pay: take-home × 15 / 100. On $5,000 a month of take-home pay, that is $5,000 × 15 / 100 = $750.00 a month. The monthly payment is what the loan buys: a payment of $750.00 a month buys a loan of $38,331.51 over 60 months at 6.5% APR, because the annuity factor is 51.1087 and $750.00 × 51.1087 = $38,331.51. The max car price is the max loan plus what you pay up front: $38,331.51 + $5,000.00 down + $2,000.00 trade-in = $45,331.51. That is the identity the whole calculator turns on: max price = max loan + down + trade-in. A $30,000 car needs a $23,000.00 loan ($30,000.00 − $5,000.00 − $2,000.00), which costs $450.02 a month ($23,000.00 / 51.1087) and $4,001.28 of total interest ($450.02 × 60 − $23,000.00). The verdict is UNDER BUDGET by $299.98 a month ($750.00 − $450.02).
| Scenario | Max payment | Max loan | Max price | Target payment | Verdict |
|---|---|---|---|---|---|
| Default | $750.00 | $38,331.51 | $45,331.51 | $450.02 | Under by $299.98 |
| Take-home $4,000 | $600.00 | $30,665.21 | $37,665.21 | $450.02 | Under by $149.98 |
| Payment 10% | $500.00 | $25,554.34 | $32,554.34 | $450.02 | Under by $49.98 |
| Payment 20% | $1,000.00 | $51,108.68 | $58,108.68 | $450.02 | Under by $549.98 |
| Term 36 months | $750.00 | $24,470.62 | $31,470.62 | $704.93 | Under by $45.07 |
| Term 72 months | $750.00 | $44,616.49 | $51,616.49 | $386.63 | Under by $363.37 |
| APR 9% | $750.00 | $36,130.03 | $43,130.03 | $477.44 | Under by $272.56 |
| APR 3% | $750.00 | $41,739.27 | $48,739.27 | $413.28 | Under by $336.72 |
| Down $0, trade $0 | $750.00 | $38,331.51 | $38,331.51 | $586.98 | Under by $163.02 |
| Target $50,000 | $750.00 | $38,331.51 | $45,331.51 | $841.34 | Over by $91.34 |
| Target $45,000 | $750.00 | $38,331.51 | $45,331.51 | $743.51 | Under by $6.49 |
| Target $7,000 | $750.00 | $38,331.51 | $45,331.51 | $0.00 | Pay cash |
At the defaults — take-home $5,000, payment 15%, down $5,000, trade-in $2,000, term 60 months, APR 6.5%, target $30,000 — the max monthly payment is $750.00, the annuity factor is 51.1087, the max loan is $38,331.51, the max car price is $45,331.51, the target loan is $23,000.00, the target monthly payment is $450.02, and the total interest on the target is $4,001.28. Check the identities: max price = max loan + down + trade-in ($38,331.51 + $5,000.00 + $2,000.00 = $45,331.51), and target payment × term − target loan = total interest ($450.02 × 60 − $23,000.00 = $4,001.28).
Setup: take-home $5,000, payment 15%, down $5,000, trade-in $2,000, term 60 months, APR 6.5%, target $30,000.
Line 1 — the max monthly payment. $5,000 × 15 / 100 = $750.00.
Line 2 — the annuity factor. r = 6.5 / 100 / 12 = 0.0054167; f = (1 − (1 + r)^−60) / r = 51.1087. The factor is how many dollars of loan one dollar a month buys.
Line 3 — the max loan. $750.00 × 51.1087 = $38,331.51.
Line 4 — the max car price. $38,331.51 + $5,000.00 + $2,000.00 = $45,331.51.
Line 5 — the target loan. $30,000.00 − $5,000.00 − $2,000.00 = $23,000.00.
Line 6 — the target monthly payment. $23,000.00 / 51.1087 = $450.02.
Line 7 — the total interest. $450.02 × 60 − $23,000.00 = $4,001.28.
Line 8 — the verdict. $750.00 − $450.02 = $299.98, UNDER BUDGET.
Reverse: the take-home pay for a $1,000.00 a month max payment at 15% is $6,666.67 (exact $6,666.6667). The take-home pay to afford a $50,000 car at 15% is $5,608.96 (exact $5,608.9625); at $5,608.96 the max payment is $841.34. The down payment to afford a $50,000 car at $750.00 a month with a $2,000.00 trade-in is $9,668.49 (exact $9,668.4903); $9,668.49 + $2,000.00 + $38,331.51 = $50,000.00 exactly. The loan term to afford a $50,000 car at $750.00 a month is 69 months (exact 68.8385 months); at 69 months the payment is $748.55 ($1.45 under), at 68 months it is $757.64 ($7.64 over) — 69 is the nearest. The max APR to afford a $50,000 car at $750.00 a month over 60 months is 1.80% (exact 1.8033%); at 1.80% the payment is $749.94 (6¢ under), at 1.81% it is $750.12 — 1.80% is the nearest.
Take-home $4,000: max payment $600.00, max loan $30,665.21, max price $37,665.21; UNDER by $149.98. A $1,000 pay cut costs $7,666.30 of car.
Payment 10%: max payment $500.00, max loan $25,554.34, max price $32,554.34; UNDER by $49.98. The stricter percentage leaves almost no headroom on a $30,000 car.
Payment 20%: max payment $1,000.00, max loan $51,108.68, max price $58,108.68; UNDER by $549.98. Five more points buys $12,777.17 of car — and $250.00 more a month of payment.
Term 36 months: max loan $24,470.62, max price $31,470.62, target payment $704.93, interest $2,377.37; UNDER by $45.07. The short term barely fits the $30,000 car, but saves $1,623.91 of interest.
Term 72 months: max loan $44,616.49, max price $51,616.49, target payment $386.63, interest $4,837.24; UNDER by $363.37. Twelve more months buys $6,284.98 of car and costs $835.96 more interest on the $30,000 car.
APR 9%: max loan $36,130.03, max price $43,130.03, target payment $477.44, interest $5,646.53; UNDER by $272.56. Two and a half points of APR costs $2,201.48 of car and $1,645.25 of interest.
APR 3%: max loan $41,739.27, max price $48,739.27, target payment $413.28, interest $1,796.79; UNDER by $336.72. Cheap credit is worth $3,407.76 of car on the same payment.
Down $0, trade $0: max price $38,331.51, target loan $30,000.00, target payment $586.98, interest $5,219.07; UNDER by $163.02. No cash up front means the whole $30,000 is borrowed.
Target $50,000: target loan $43,000.00, payment $841.34, interest $7,480.66; OVER BUDGET by $91.34 a month (FLIP). The $50,000 car is $4,668.49 over the max price, and the payment is $91.34 over the max.
Target $45,000: target loan $38,000.00, payment $743.51, interest $6,610.82; UNDER by $6.49. The $45,000 car just fits — $331.51 under the max price, $6.49 under the max payment.
Target $7,000: target loan $0.00, payment $0.00, interest $0.00; CASH — pay cash, no loan needed. The down payment and trade-in cover the whole price.
Reverse — the other way round: the take-home for a $1,000.00 max payment is $6,666.67 (exact $6,666.6667); the take-home for a $50,000 car is $5,608.96 (exact $5,608.9625); the down payment for a $50,000 car at $750.00 a month is $9,668.49 (exact $9,668.4903); the term for a $50,000 car at $750.00 a month is 69 months (exact 68.8385 months); the max APR for a $50,000 car at $750.00 a month is 1.80% (exact 1.8033%).
The model assumes the car payment is the only car cost counted: insurance, gas, maintenance, and registration are not in the 15%, so check them separately — a $750.00 payment with $200.00 of insurance is really $950.00 a month of car. It assumes the take-home pay is monthly and after tax, the APR is fixed for the whole term, and the down payment and trade-in are paid at the sale. It does not model sales tax, dealer fees, or a balloon payment. With take-home $0, the max payment is $0.00, the max loan is $0.00, the max price is $7,000.00 (down + trade-in only), and the $30,000 car is OVER by $450.02. With APR 0%, the factor is 60, the max loan is $45,000.00, the max price is $52,000.00, the target payment is $383.33, the interest is $0.00, and the verdict is UNDER by $366.67. With a 12-month term, the max loan is $8,690.97, the max price is $15,690.97, the target payment is $1,984.82, the interest is $817.81, and the verdict is OVER by $1,234.82. With an 84-month term, the max loan is $50,506.97, the max price is $57,506.97, the target payment is $341.54, the interest is $5,689.11, and the verdict is UNDER by $408.46. Monthly figures are rounded to the cent, so monthly × 12 can differ from the annualised total by a few cents; totals are computed from unrounded values, so rounded parts may differ by a cent from their rounded sum.
| Output | Formula | What it means |
|---|---|---|
| Max monthly payment | take-home × pct / 100 | $750.00. |
| Annuity factor | (1 − (1+r)^−n) / r | 51.1087. |
| Max loan | max payment × factor | $38,331.51. |
| Max car price | max loan + down + trade-in | $45,331.51. |
| Target loan | target − down − trade-in | $23,000.00. |
| Target monthly payment | target loan / factor | $450.02. |
| Total interest on the target | target payment × term − target loan | $4,001.28. |
| Monthly gap | max payment − target payment | $299.98. |
| Verdict | target payment vs max payment | Under budget by $299.98 a month. |
| Take-home for a $1,000/mo payment | 1,000 / 0.15 | $6,666.6667 → $6,666.67. |
| Take-home for a $50,000 car | payment / 0.15 | $5,608.9625 → $5,608.96. |
| Down payment for a $50,000 car | 50,000 − max loan − trade-in | $9,668.4903 → $9,668.49. |
| Term for a $50,000 car | solve 43,000 / f = 750 | 68.8385 months → 69 months. |
| Max APR for a $50,000 car | solve 43,000 / f = 750 | 1.8033% → 1.80%. |
| Take-home $4,000 | same model | Max price $37,665.21, target payment $450.02 — Under budget by $149.98 a month. |
| Payment 10% | same model | Max price $32,554.34, target payment $450.02 — Under budget by $49.98 a month. |
| Payment 20% | same model | Max price $58,108.68, target payment $450.02 — Under budget by $549.98 a month. |
| Term 36 months | same model | Max price $31,470.62, target payment $704.93 — Under budget by $45.07 a month. |
| Term 72 months | same model | Max price $51,616.49, target payment $386.63 — Under budget by $363.37 a month. |
| APR 9% | same model | Max price $43,130.03, target payment $477.44 — Under budget by $272.56 a month. |
| APR 3% | same model | Max price $48,739.27, target payment $413.28 — Under budget by $336.72 a month. |
| Down $0, trade $0 | same model | Max price $38,331.51, target payment $586.98 — Under budget by $163.02 a month. |
| Target $50,000 | same model | Max price $45,331.51, target payment $841.34 — Over budget by $91.34 a month. |
| Target $45,000 | same model | Max price $45,331.51, target payment $743.51 — Under budget by $6.49 a month. |
| Target $7,000 | same model | Max price $45,331.51, target payment $0.00 — Pay cash — no loan needed. |
The math is exact for the numbers you enter: max payment = take-home × pct / 100, factor = (1 − (1+r)^−n) / r, max loan = max payment × factor, max car price = max loan + down + trade-in, target loan = target − down − trade-in, target payment = target loan / factor, total interest = target payment × term − target loan. What the model cannot do is know your real costs: check the insurance, because a $750.00 payment with $200.00 of insurance is really $950.00 a month of car, and check the APR, because the rate you are offered is the rate that decides the loan. It assumes the take-home pay is monthly and after tax, the APR is fixed for the whole term, and the down payment and trade-in are paid at the sale. It leaves out sales tax, dealer fees, insurance, gas, maintenance, and registration. It is an affordability calculator, not a loan offer: for the loan itself, see the car loan payoff calculator; for whether to lease or buy, see the lease vs buy car calculator.
Bright Side Kit. "Car Affordability Calculator: How Much Car in 2026" https://brightoolbox.com/car-affordability-calculator/ Accessed October 25, 2026.$750.00 a month, a $38,331.51 loan, a $45,331.51 car. 15% of $5,000 is $750.00 a month. At 6.5% APR over 60 months, $750.00 a month buys a $38,331.51 loan (factor 51.1087), and with $5,000 down and a $2,000 trade-in the max car price is $45,331.51. A $30,000 car costs $450.02 a month — under budget by $299.98.
Multiply the payment by the annuity factor. The factor is (1 − (1+r)^−n) / r, where r is the monthly rate. At 6.5% APR over 60 months the factor is 51.1087, so $750.00 a month buys $750.00 × 51.1087 = $38,331.51 of loan. At 0% APR the factor is just the term: 60.
20% down, a term of 4 years or less, and a payment of 10% or less of your gross monthly income. It is a stricter alternative to the 15%-of-take-home rule this calculator uses: on $5,000 of take-home pay the 10% payment is $500.00 a month, which buys a $25,554.34 loan and a $32,554.34 car at 6.5% over 60 months. This calculator does not model the 20/4/10 rule — it is a stricter check you apply yourself.
Not on the 15% rule — the payment is $841.34 a month, $91.34 over the $750.00 max. To afford it, you would need take-home pay of $5,608.96 a month at 15% (exact $5,608.9625), or a down payment of $9,668.49 at $750.00 a month (exact $9,668.4903), or a 69-month term (exact 68.8385 months), or an APR of 1.80% (exact 1.8033%). A $45,000 car fits: $743.51 a month, under budget by $6.49.
Whatever your down payment and trade-in cover, with no loan at all. A $7,000 car is covered by the $5,000 down payment and the $2,000 trade-in: the target loan is $0.00, the payment is $0.00, and the interest is $0.00 — pay cash, no loan needed. At APR 0% the max loan is $45,000.00 and the max price is $52,000.00, with $0.00 interest.
Yes — but it costs more interest. At 36 months the max loan is $24,470.62 and the max price is $31,470.62; at 72 months the max loan is $44,616.49 and the max price is $51,616.49. On the $30,000 car, the 36-month term costs $2,377.37 of interest and the 72-month term costs $4,837.24. At 12 months the max loan is only $8,690.97 and the $30,000 car is over budget by $1,234.82 a month.