Debit vs Credit Card Calculator: Which Costs Less in 2026?

How the debit vs credit card comparison is worked out

On the defaults — $2,000.00 a month, 2% rewards, 24% APR, 25% of the balance carried, a $95 annual fee — the credit card rewards are $480.00, the interest is $120.00, the credit card net is $265.00, the debit card net is $0.00, and the winner is the credit card by $265.00. The whole calculation is four moves: multiply the monthly spending by 12 and the rewards rate for the rewards, multiply the monthly spending by the fraction carried and the APR for the interest, subtract the interest and the fee for the credit net, and take the higher net as the winner.

Five things about the model are worth stating plainly. First, the rewards are the monthly spending times 12 times the rewards rate — $2,000.00 × 12 × 2% = $480.00. Second, the interest is the monthly spending times the fraction of the balance carried times the APR — the same amount is spent and the same fraction carried every month, so it is one carried balance, charged APR ÷ 12 each month for 12 months: $2,000.00 × 25% × 24% = $120.00. Third, the credit card net is the rewards minus the interest minus the annual fee — $480.00 − $120.00 − $95.00 = $265.00. Fourth, the debit card net is $0 — no rewards, no interest, no fee — because the model assumes the debit card pays no cashback. And fifth, the winner is the higher net value, decided from the rounded net gap — a rounded gap of exactly $0.00 is a tie.

The worked example, line by line

Setup: $2,000.00 a month, 2% rewards, 24% APR, 25% of the balance carried, $95 annual fee.

Line 1 — work out the rewards. A year of spending is $2,000.00 × 12 = $24,000.00, so the rewards are $24,000.00 × 2% = $480.00.

Line 2 — work out the interest. The balance carried each month is $2,000.00 × 25% = $500.00, and the interest on it over a year at 24% APR is $500.00 × 24% = $120.00.

Line 3 — take the credit card net. The net is $480.00 − $120.00 − $95.00 = $265.00.

Line 4 — take the winner. The debit card net is $0.00, so the credit card wins by $265.00. Rounding convention: totals are computed from unrounded values, so rounded parts may differ by a cent from their rounded sum.

Every branch, checked

Carried fraction 100% (never pay it off): Monthly spending $2,000.00, rewards 2.00%, APR 24.00%, 100.00% carried, fee $95.00: credit rewards $480.00, interest $480.00, net -$95.00; debit net $0.00; debit wins by $95.00 — carry the whole balance and the interest is $480.00, exactly the rewards — and the fee is left over, so the debit card wins by $95.00.

Rewards rate 1%: Monthly spending $2,000.00, rewards 1.00%, APR 24.00%, 25.00% carried, fee $95.00: credit rewards $240.00, interest $120.00, net $25.00; debit net $0.00; credit wins by $25.00 — half the rewards is $240.00, and the net shrinks to $25.00 — the credit card still wins, but only just.

Annual fee $0: Monthly spending $2,000.00, rewards 2.00%, APR 24.00%, 25.00% carried, fee $0.00: credit rewards $480.00, interest $120.00, net $360.00; debit net $0.00; credit wins by $360.00 — no fee lifts the net to $360.00 and the credit card wins by $360.00.

APR 0% (intro 0% APR): Monthly spending $2,000.00, rewards 2.00%, APR 0.00%, 25.00% carried, fee $95.00: credit rewards $480.00, interest $0.00, net $385.00; debit net $0.00; credit wins by $385.00 — no interest at all, so the net is the rewards minus the fee: $385.00, and the credit card wins by $385.00.

Monthly spending $5,000: Monthly spending $5,000.00, rewards 2.00%, APR 24.00%, 25.00% carried, fee $95.00: credit rewards $1,200.00, interest $300.00, net $805.00; debit net $0.00; credit wins by $805.00 — two and a half times the spending, two and a half times the rewards and the interest: the net is $805.00.

Rewards rate 5%: Monthly spending $2,000.00, rewards 5.00%, APR 24.00%, 25.00% carried, fee $95.00: credit rewards $1,200.00, interest $120.00, net $985.00; debit net $0.00; credit wins by $985.00 — 5% back is $1,200.00 of rewards, and the net is $985.00.

Carried fraction 50%: Monthly spending $2,000.00, rewards 2.00%, APR 24.00%, 50.00% carried, fee $95.00: credit rewards $480.00, interest $240.00, net $145.00; debit net $0.00; credit wins by $145.00 — carry half the balance and the interest doubles to $240.00, so the net falls to $145.00.

The reverses, worked backwards

Rewards rate for a tie: 0.90% — the exact rewards rate is 0.8958%. At the displayed 0.90% the rewards are $216.00 and the net is $1.00 — credit ahead by $1.00, rounding. 0.89% gives rewards $213.60 and net −$1.40. The star is a PERCENT.

Carried fraction for a tie: 80.21% — the exact fraction is 80.2083%. At the displayed 80.21% the interest is $385.01 and the net is −$0.01 — debit wins by $0.01, rounding. 80.20% gives interest $384.96 and net $0.04; 80.22% gives interest $385.06 and net −$0.06. The star is a PERCENT.

APR for a tie: 77.00% — the exact APR is 77.0000%. At the displayed 77.00% the interest is $385.00 and the net is $0.00 — an exact tie. 76% gives interest $380.00 and net $5.00; 78% gives interest $390.00 and net −$5.00. The star is a PERCENT.

Annual fee for a tie: $360.00 — the exact fee is 360.0000. At $360.00 the net is $0.00 — an exact tie. The star is DOLLARS.

Monthly spending for $500.00 net: $3,305.56 — the exact spending is 3305.5556. At $3,305.56 the net is $500.00 (exact to the cent). $3,305 gives $499.90; $3,306 gives $500.08. The star is DOLLARS.

Monthly spending for net to reach $1,000: $6,084 — the smallest whole-dollar spending that clears $1,000 of net. At $6,084 the net is $1,000.12; $6,083 gives $999.94. This is a step reverse: spending comes in whole dollars, so there is no exact in-between. The star is DOLLARS.

What the defaults assume

The defaults are $2,000.00 a month, 2% rewards, 24% APR, 25% of the balance carried, a $95 annual fee — credit rewards $480.00, interest $120.00, net $265.00, and the credit card wins by $265.00. With monthly spending of $0, Monthly spending $0.00, rewards 2.00%, APR 24.00%, 25.00% carried, fee $95.00: credit rewards $0.00, interest $0.00, net -$95.00; debit net $0.00; debit wins by $95.00 — no spending, no rewards, and the fee is the whole story. With a rewards rate of 0%, Monthly spending $2,000.00, rewards 0.00%, APR 24.00%, 25.00% carried, fee $95.00: credit rewards $0.00, interest $120.00, net -$215.00; debit net $0.00; debit wins by $215.00 — no rewards, only interest and the fee. With an annual fee of $500, Monthly spending $2,000.00, rewards 2.00%, APR 24.00%, 25.00% carried, fee $500.00: credit rewards $480.00, interest $120.00, net -$140.00; debit net $0.00; debit wins by $140.00 — the fee alone sinks the credit card. With monthly spending of $10,000, Monthly spending $10,000.00, rewards 2.00%, APR 24.00%, 25.00% carried, fee $95.00: credit rewards $2,400.00, interest $600.00, net $1,705.00; debit net $0.00; credit wins by $1,705.00 — the rewards scale with the spending. With a rewards rate of 10%, Monthly spending $2,000.00, rewards 10.00%, APR 24.00%, 25.00% carried, fee $95.00: credit rewards $2,400.00, interest $120.00, net $2,185.00; debit net $0.00; credit wins by $2,185.00 — $2,400.00 of rewards. With a carried fraction of 0% and an annual fee of $0, Monthly spending $2,000.00, rewards 2.00%, APR 24.00%, 0.00% carried, fee $0.00: credit rewards $480.00, interest $0.00, net $480.00; debit net $0.00; credit wins by $480.00 — the pure rewards case. Rounding convention: totals are computed from unrounded values, so rounded parts may differ by a cent from their rounded sum.

Output · formula · meaning

Who uses this

• The cardholder who carries a quarter of the balance: they learn the credit card wins by $265.00 on the defaults — and they check the 0.90% reverse to see the rewards rate that would tie the two cards.
• The cardholder who never pays it off: they learn carrying the full balance flips the answer — the debit card wins by $95.00 — and they check the 80.21% reverse to see how much of the balance they can carry before the debit card takes it.
• The no-fee card seeker: they learn a $0 fee lifts the net to $360.00 — and they check the $360.00 reverse to see the fee that would exactly wipe the credit card’s advantage out.
• The big spender at $5,000 a month: they learn the net is $805.00 — and they check the $3,305.56 reverse to see the spending it takes to clear $500.00 of net, and the $6,084 step to see what it takes to clear $1,000.00.

Accuracy & limitations

The math is first-principles: the rewards are the monthly spending times 12 times the rewards rate; the interest is the monthly spending times the fraction of the balance carried times the APR; the credit card net is the rewards minus the interest minus the annual fee; the debit card net is $0; the winner is the higher net value, decided from the rounded net gap. Every figure is rounded to cents half-up, and the totals are computed from unrounded values, so rounded parts may differ by a cent from their rounded sum. What the model cannot do is tell you what YOUR cards will cost: it ignores grace periods, which can make the interest zero if you pay in full; it ignores minimum payments, which decide how fast a carried balance shrinks; it ignores interest compounding within the year, which makes a real carried balance cost a little more than APR ÷ 12 each month; it assumes the debit card pays no cashback, while some debit cards pay a little; it ignores rewards caps and rotating categories, which change what a real credit card pays; and it ignores that credit-card rewards are usually paid as statement credit, not cash. Use it to size the trade-off, then check the card’s actual terms before you carry a balance.

Frequently asked questions