Free, cited, and wrong-answer proof.
Every calculator here is built the way we build the paid product: the rule is fetched from the SEC or the State of Delaware, implemented literally, then tested against the issuing authority's own published examples and a second independent computation before it ships. Where a question needs judgment rather than arithmetic, the tool says so instead of guessing. No signup, no email required, nothing you type leaves your browser.
SEC deadline calendar
Your 10-K, all three 10-Qs, Form 5, and the proxy window for the year — from your fiscal year end and filer status, with weekend and holiday rolls and Rule 12b-25 outside dates.
Optional email reminders 14, 5, and 1 day before each deadline.
Form 10-K Instr. A · Form 10-Q Instr. A.1 · 17 CFR 240.0-3
Form 8-K deadline helper
Pick the item, enter the trigger date, get the filing date — including what happens when the event lands on a weekend or a day the Commission is closed, and which items start their clock somewhere other than the event.
There is no NT 8-K. The tool says so.
Form 8-K Gen. Instr. B.1 · 17 CFR 240.12b-25(a)
83(b) election deadline calculator
Thirty days after transfer, and the only tax deadline with no cure. Enter the transfer date, get the postmark date — with the weekend and District of Columbia holiday rules that move it applied, Emancipation Day included.
A calculator that only knows federal holidays is a day early on April 16. This one is not.
IRC §83(b) · IRS Form 15620 · 26 U.S.C. §7503 · D.C. Code §1-612.02
Delaware franchise tax calculator
Both methods, side by side. Delaware bills the Authorized Shares number by default; most companies legally owe far less under Assumed Par Value Capital. The difference is routinely tens of thousands of dollars.
The state's own worked examples are in our test suite.
8 Del. C. §503 · corp.delaware.gov
Why give these away
A calculator you run once a year is not a subscription, so we do not pretend it is one. These exist so you can check our arithmetic against your own before trusting us with anything that matters. When you want the same discipline applied to your actual grants, insiders, and filings — deadlines watched on your data, Forms 4 drafted from it, ASC 718 expense that ties — that is the paid product.