# Filing Cost Calculator

> Work out what filing accounts and CT600s costs an accountancy firm with Tax Optimiser at any number of clients: the cheapest credit packs and the cost per client.

Enter how many client companies you file for in a year to see the cheapest credit packs to buy and what each client's accounts and CT600 cost you.

Use the calculator: https://www.taxoptimiser.co.uk/calculators/filing-cost

Example: A firm filing for 80 client companies a year pays least by buying 1 Practice pack of 100 credits for £600 + VAT, which is £7.50 a client and leaves 20 credits for next year. Buying 80 single credits would cost £800 + VAT.

## How credits work

One credit files one client company's accounts to Companies House and its CT600 to HMRC for one period, with any amendments included. Preparing the accounts and the return costs nothing: the credit is used when you submit. Credits do not expire, and there is no subscription or per-user fee.

## Why the next pack up can be cheaper

Packs can be mixed, so the calculator looks for the cheapest combination that covers your clients. Because larger packs cost less per credit, a pack bigger than you need is often cheaper than a smaller pack topped up with single credits, and the credits left over carry forward to next year.

## Dormant clients

A dormant period uses a dormant credit, which is bought singly in any quantity at a lower price. It covers the dormant accounts and, where HMRC has asked for one, the nil CT600.

## Credit packs

One credit files one client company's accounts and CT600 for one period. Prices exclude VAT.

| Pack | Credits | Price | Per credit |
| --- | --- | --- | --- |
| Pay-as-you-go | 1 | £10 | £10 |
| Starter | 25 | £200 | £8 |
| Practice | 100 | £600 | £6 |
| Growth | 250 | £1,250 | £5 |
| Scale | 500 | £2,000 | £4 |
| Enterprise | 1,000 | £3,000 | £3 |

Dormant credits are £2 + VAT each, in any quantity.

## Cost per client by number of clients

The cheapest mix of packs for each number of client companies, none of them dormant. Prices exclude VAT.

| Clients a year | Cheapest to buy | Cost | Per client | Credits left over |
| --- | --- | --- | --- | --- |
| 10 | 10 × Pay-as-you-go | £100 | £10.00 | 0 |
| 20 | 1 × Starter | £200 | £10.00 | 5 |
| 40 | 1 × Starter + 15 × Pay-as-you-go | £350 | £8.75 | 0 |
| 80 | 1 × Practice | £600 | £7.50 | 20 |
| 150 | 1 × Practice + 2 × Starter | £1,000 | £6.67 | 0 |
| 300 | 1 × Growth + 2 × Starter | £1,650 | £5.50 | 0 |
| 600 | 1 × Scale + 1 × Practice | £2,600 | £4.33 | 0 |
| 1,000 | 1 × Enterprise | £3,000 | £3.00 | 0 |

## Frequently asked questions

### How much does it cost an accountant to file a CT600 and accounts?

From £3 + VAT a client with the Enterprise pack of 1,000 credits, up to £10 + VAT for a single credit. One credit covers the accounts to Companies House and the CT600 to HMRC.

### Do credits expire?

No. Credits you do not use this year carry forward.

### Is there a subscription or a per-user fee?

No. A firm pays only for the credits it buys, and any number of staff can use them.

### Does a long period of accounts use two credits?

No. A period of accounts longer than 12 months needs two CT600s, but it is one period and uses one credit.

## Related calculators

- [Company Accounts Type Checker](https://www.taxoptimiser.co.uk/calculators/accounts-type-checker.md): Micro-entity, small or dormant accounts, and whether the free Companies House service is still open.
- [Corporation Tax Deadlines Calculator](https://www.taxoptimiser.co.uk/calculators/corporation-tax-deadlines.md): Payment, CT600 and Companies House dates for any accounting period.
- [Late Filing Penalty Calculator](https://www.taxoptimiser.co.uk/calculators/late-filing-penalties.md): Companies House and HMRC penalties for late accounts and a late CT600.
- [Corporation Tax Calculator](https://www.taxoptimiser.co.uk/calculators/corporation-tax.md): Estimate Corporation Tax for a UK limited company with marginal relief.

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Last updated 11 October 2026. Guidance only: a general estimate, not tax advice. Published by Tax Optimiser, UK tax filing software (https://www.taxoptimiser.co.uk).