Yes! The earlier you pay off your ISA, the cheaper it will be. You can calculate the amount you’d owe by taking your initial funding amount times the corresponding payment cap.

Years since disbursement |
Payment cap |

<1 |
1.25 |

1 |
1.25 |

2 |
1.5 |

3 |
1.75 |

4 |
2.0 |

5 |
2.25 |

6+ |
2.5 |