Examples
Examples
Try the starting example
- Credits: issuer, balance $, expiry date
- Shop,100,2026-10-31 Shop,50,2026-11-30
- Eligible purchases: name, issuer, purchase date, amount $
- Shoes,Shop,2026-10-25,80 Bag,Shop,2026-11-10,80
- Credit redeemed ($)
- $130.00
- Additional cash required ($)
- $30.00
- Unused credit balances ($)
- $20.00
- Purchase funding plan
- Shoes: credit 80, cash 0; Bag: credit 50, cash 30
Try another scenario
- Credits: issuer, balance $, expiry date
- Shop,100,2026-10-31 Shop,50,2026-11-30
- Eligible purchases: name, issuer, purchase date, amount $
- Shoes,Shop,2026-10-25,80 Bag,Shop,2026-10-30,80
- Credit redeemed ($)
- $150.00
- Additional cash required ($)
- $10.00
- Unused credit balances ($)
- $0.00
- Purchase funding plan
- Shoes: credit 80, cash 0; Bag: credit 70, cash 10
Calculation method
Calculation method
Credit redeemed ($)
Process purchases in date order; use same-issuer credits by earliest expiry, accepting credits through their expiry date inclusive.
Additional cash required ($)
Purchase amounts minus applied credit.
Unused credit balances ($)
Original credit balances minus redemptions, including unused amounts that expire before later purchases.
Purchase funding plan
Show each purchase’s credit contribution and residual cash; credits never transfer between issuers.
Symbols and units
- a
- Credits: issuer, balance $, expiry date
- b
- Eligible purchases: name, issuer, purchase date, amount $
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions & limits
Assumptions & limits
- A first-expiring-credit allocation for purchases you have already marked eligible. It assumes no minimum spend, partial-redemption restriction, exchange-rate change or expiry extension beyond what you enter.
Are these inputs private?
These calculations run in your browser. A shared link contains the values you choose to share. Only questions submitted to the separate AI finder are sent to OpenAI.
Further reading
OpenStax: arithmetic and geometry ↗
Background reading; this does not imply endorsement or independent review of SumFizz.