Countdown Calculator
The start date is editable and defaults to the user’s local calendar date. Future spans are positive and past spans negative.
Last updated · View algorithm, constants and default inputs (JSON)
Results
About this calculator
The start date is editable and defaults to the user’s local calendar date. Future spans are positive and past spans negative.
Worked example
calculated with the default values below
Target date 2027-01-31 · Starting date 2026-10-31 · Count both start and target dates No Days remaining 92 days · Weeks remaining 13.1 weeks · Months remaining 3.0 months · Hours remaining 2,208 h · Including the start date in the direction counted 93 days · Weekdays 65 days · Weekend days 27 days · Target falls on a Sunday · Status Still to come
Method and assumptions
The start date is editable and defaults to the user’s local calendar date. Future spans are positive and past spans negative. Inclusive counting adds one date in that direction; weekday and weekend counts are unsigned counts over the same included dates. Months are an average conversion using 30.4375 days, not calendar months. Holidays are not removed.
General background references
Disclaimer
These calculators give general date results. Public holidays, working-day conventions and time-zone rules are set locally and change, so confirm against the official calendar for anything legally or contractually binding.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
Δ = (T − S)/86400000; counted = sign(Δ) × (|Δ| + inclusive); weeks = counted/7; months ≈ counted/30.4375
Months are an average conversion using 30.4375 days, not calendar months. Holidays are not removed.
Frequently asked questions
Why does the calculator count today as an extra day?
The start date is editable and defaults to the user’s local calendar date. Future spans are positive and past spans negative. Inclusive counting adds one date in that direction; weekday and weekend counts are unsigned counts over the same included dates. Months are an average conversion using 30.4375 days, not calendar months. Holidays are not removed.