Flatpay · Retention Payback Calculator

Customer Current Situation

Annual TPV £/year

Monthly TPV computed

Current or competitor rate % — for savings comparison

Surcharge TPV share % of TPV under surcharge

AMEX TPV share % of TPV via AMEX

Retention Offer

Rate levers — the main bargaining variables

New base rate % — main lever

Effective blended rate what merchant actually pays

Surcharge rate % — applied to surcharged TPV

AMEX rate % — separate rate; uncheck for legacy

Hardware & upfront

Terminals (#)

Display options

Show customer savings vs current rate

Outputs

Payback

–

CAC (effective)

£–

Monthly profit

£–

Yearly margin

–

CAC Breakdown

Monthly Profit Breakdown

Cost Parameters & Commission Table

UK card cost (non-surch) %

Surcharge cost %

Surcharge buy-rate %

AMEX cost %

Settlement £/mo

Terminal running £/mo

Terminal amort £/mo

POS running £/mo

POS Premium amort £/mo

POS Pro amort £/mo

Terminal onboarding £

POS onboarding £

Driving allowance £

Salary share £ SL £50 + Cost per conv. booking £350 + BL £50 (same for both products)

Weighted bonuses — Terminal £ AMEX 10 + QInstall 25 + OG 20 + IH 11 (no POS vol / no upfront comm)

Weighted bonuses — POS £ terminal bonuses + POS vol £200 (upfront comm computed live)

SM upfront commission % POS only — % of actual upfront fee charged

Social costs %

Net commission discount %

Terminal discount %

Payback threshold (mo)

Margin threshold (%)

Defaults from POS_payback - FS.xlsx · SM (May 2026) - POS. Adjusting here updates the calculator live — switch back to the Calculator tab to see the impact.