What the taxable base is (the short version)
The base imponible, or taxable base, is the figure the tax rate is applied to, and it is not exactly your profit. The starting point is the accounting result from your profit and loss account: the year's income minus its expenses. That result is then corrected by ajustes extracontables, tax adjustments that add or remove items: fines and penalties, or the corporate tax expense itself, are not deductible and get added back, for example.
If you also have negative taxable bases (BINs, tax losses declared in previous years), they can be offset and shrink the base before the rate is applied.
For the estimator, enter your best forecast of the taxable base. If all you have is an estimated accounting profit, use it as an approximation: in a small SL with few adjustments the two figures usually land close together, but they are not the same thing.
The three rate regimes: which box to tick
The estimator asks you to choose between three situations, matching the tax rates for 2026:
- Newly created company: 15%. It applies in the first tax period in which the taxable base is positive and in the following one, provided the company carries out a genuine business activity. The conditions are in article 29 of the Corporate Income Tax Act (Ley 27/2014): the company cannot be part of a group, the activity cannot have been carried on before by a related person or entity, and it cannot be an entidad patrimonial (a company that only holds assets). A first year in the red does not use up the window: the clock starts with the first positive base.
- Micro-company: the 19% and 21% scale. For companies whose net turnover (INCN, importe neto de la cifra de negocios) is under 1 million euros. In 2026 the first 50,000 euros of base are taxed at 19% and the rest at 21%. From 2027 the scale drops to 17% and 20%.
- General rate: 25%. The default rule if neither of the above fits.
While the 15% window lasts, it beats the micro-company scale, because it is lower than either of its bands. Once the two profitable years are used up, or if you do not qualify, you move to the micro-company scale or the general rate depending on your turnover. All the rates are collected in the 2026 tax figures.
What the calculator leaves out
The estimator applies the rate to the base you enter, and nothing more. It deliberately leaves out everything that depends on your specific case:
- Tax adjustments: it assumes the figure you enter is already the taxable base, not the accounting result.
- BIN offsetting: if you carry unused losses from previous years, your real base may be lower.
- Deductions and credits: they reduce the tax after the rate is applied and depend on each business.
- Prepayments already made: whatever you paid during the year through the modelo 202 is subtracted at the end, so the amount actually due in July can be well below the estimated tax.
If the base you enter is realistic, those elements can only reduce what you end up paying; that is why the estimated figure works well as a reasonable ceiling for your provision.
An estimate, not a return: from the number to the modelo 200
The real settlement of corporate income tax happens on the modelo 200, which for a financial year matching the calendar year is filed from 1 to 25 July of the following year. During the year, the tax is also prepaid in instalments through the modelo 202 in April, October and December, calculated from your last return that has already fallen due.
The estimator's result does what any estimate does: it tells you how much to set aside each month, lets you compare profit scenarios and spares you a surprise in July. It replaces neither the year-end close nor the return itself.
kontora does the heavy part of that journey: it keeps your SL's books, prepares the modelo 200 and 202 drafts box by box and reminds you of every deadline; filing on the AEAT website is still done by you. If your company is new, the guide to corporate income tax in year one explains the full cycle, and the 2026-2027 tax calendar gathers all the dates.
Frequently asked questions
What figure do I enter if I only know my estimated profit?
Does a newly incorporated SL always tick the new-company box?
Can I combine the 15% with the 19% and 21% scale?
Why might my real tax differ from the estimate?
Does this calculator file anything with the tax office?
Rather have this calculated for you?
kontora generates your tax forms box by box, tells you how much to set aside and reminds you before every deadline.