Estimate your Monzo Flex monthly payments, interest, and total cost based on real APR rates and repayment terms.

Monzo Flex charges 0% APR on 3-month plans and 24% APR on 6 and 12-month plans. Simple enough in theory, but the actual monthly cost depends on your purchase amount and which plan you pick, and Monzo doesn't show you a breakdown before you commit.

I built this after buying something and genuinely not being sure which plan worked out cheaper. Took about an hour to put together, and I've used it a few times since.

Monzo Flex Calculator

Purchase Amount (£)

Repayment Term (months)1 month2 months3 months4 months5 months6 months7 months8 months9 months10 months11 months12 months13 months14 months15 months16 months17 months18 months19 months20 months21 months22 months23 months24 months

Monthly Payment: £5.26

Total Interest: £1.60

Total to Repay: £31.55

This is an estimate only and not financial advice. Always check the current rate directly with Monzo before committing.

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Last updated on Apr 28, 2026