Why these three
Because they are the calculations that decide how a practice feels to work in, and none of them come out of your accounts software. Your system knows what the practice received. It does not know what the contract said it should have received, what a partner can safely draw against a tax bill that has not arrived, or what a locum costs once status is priced in.
Common questions
Are these free, and is anything stored?
Free, no sign-up, and nothing is stored. They run entirely in your browser, so the figures you type never leave your device. There is no email gate in front of any of them, because a calculator you have to pay for with your contact details is an advert rather than a tool. If you would rather not type your own numbers in, the same calculations are part of the free review and we will run them from your contract statement. Nothing you enter is transmitted anywhere, so you can use them on real practice figures without worrying about where they go.
How accurate are they?
Accurate enough to tell you whether something is worth investigating, not accurate enough to file on. The global sum tool needs your weighted population rather than your list size, and if you enter list size it will overstate your income — the weighting under Carr-Hill is exactly the thing a simple calculator cannot know for you. Where a figure is an assumption the page says so. The drawings tool is the clearest example: it assumes a reserve percentage you set rather than computing your actual tax position, because that depends on each partner's other income. Treat the output as a floor to test, not a figure to draw to.
Where do the rates come from?
Primary sources, cited in the code. The global sum of £130.07 per weighted patient and the £2.18 London Adjustment come from the Statement of Financial Entitlements 2026, applying from 1 April 2026. Tax and National Insurance rates are 2026/27. If a rate changes the calculators change with it. Every rate is listed at the top of the JavaScript file that does the arithmetic, so you can check what a tool believes before you trust what it tells you — which is not something most calculators let you do.
Which should I use first?
The drawings calculator, if you only run one. Most partnership pain is not about how much the practice earns but about how much has already been drawn against tax and superannuation that have not yet been demanded. Getting that reserve right removes more stress than any other single change, and it costs nothing to model. If the number it gives you is a long way below what partners are currently taking, that is the conversation to have now rather than in January when the payment on account is due.