Calculate cash back before and after a spending or reward cap, track the amount remaining, and find the additional eligible spend needed to reach the limit.
Cash Back Cap Formula
For an offer capped by eligible spending, the amount of new spending that receives the bonus rate is:
Bonus-Rate Spend = min(New Spend, Spend Cap - Prior Eligible Spend)
Total cash back is the reward on bonus-rate spending plus the base reward on spending above the cap:
Cash Back = Bonus-Rate Spend * Bonus Rate + Spend Above Cap * Base Rate
For a dollar reward cap, the remaining bonus-rate spending capacity is:
Spend to Cap = (Reward Cap - Rewards Already Earned) / Bonus Rate
Variables:
- New Spend is additional eligible spending during the offer period
- Spend Cap is the maximum spending that earns the bonus rate
- Reward Cap is the maximum cash-back dollars allowed
- Bonus Rate is the promotional cash-back percentage
- Base Rate is the percentage earned after the cap is exhausted
Card issuers describe caps in two common ways: “5% on up to $1,500 in purchases” is a spending cap, while “earn up to $75 back” is a reward cap. Choose the wording that matches the offer because the remaining-cap units differ.
Maximum Cash Back by Spending Cap
These amounts are the maximum bonus-rate cash back before considering any base rewards earned after the spending cap.
| Bonus rate | $500 spend cap | $1,000 spend cap | $1,500 spend cap | $2,000 spend cap |
|---|---|---|---|---|
| 2% | $10 | $20 | $30 | $40 |
| 3% | $15 | $30 | $45 | $60 |
| 5% | $25 | $50 | $75 | $100 |
| 8% | $40 | $80 | $120 | $160 |
| 10% | $50 | $100 | $150 | $200 |
Example Problems
Example 1: Spending cap with base rewards.
A card earns 5% on up to $1,500 of eligible spending and 1% afterward. You have already used $1,200 of the cap and make $800 of new purchases. The first $300 earns 5%, or $15. The remaining $500 earns 1%, or $5. Total cash back is $20, a blended rate of 2.5% on the new spending.
Example 2: Dollar reward cap.
An offer pays 10% cash back up to a maximum of $50. You have already earned $20, so $30 of the cap remains. Additional spending needed to hit the cap is $30 / 10% = $300.
Frequently Asked Questions
What is the difference between a spending cap and a cash-back cap?
A spending cap limits the purchase amount that receives the bonus rate. A cash-back cap limits the reward dollars themselves. The two can be converted using the bonus rate, but the offer's exact wording determines what should be tracked.
Does spending above the cap earn nothing?
Not necessarily. Many cards revert to a base cash-back rate after the promotional cap, while some merchant offers stop earning rewards entirely. Enter zero as the base rate when no rewards apply beyond the cap.
How should returns affect the cap?
Returned purchases commonly reverse the associated rewards and may restore cap capacity, but issuer rules vary. Update the “already used” amount to match the net eligible spending or rewards shown by the issuer.
