31 forensic tools, grouped by discipline
These calculators exist to make published forensic methods visible. Each one implements the clearest form of a recognised technique, states its assumptions and requires you to supply the reference data that makes the result meaningful. They are built for students, teachers and writers — not for casework.
Every calculator in this section now carries a full explanation: what the method does, where it came from, a worked example, the mistakes people make, and — on every page — a plain statement of where the method is weakest. Where a discipline has faced scientific criticism, the page says so.
Start here
If you are not sure where to begin, these tools answer the questions readers ask most often in this section.
Crime scene investigation 3 tools
Planning tools for the practical side of scene work: how long a search will take, how many photographs are involved and how much light an area needs.
Evidence handling and continuity 3 tools
Labelling, packaging and timeline tools that support exhibit continuity. Nothing here leaves the browser, so no case detail is transmitted.
Time of death and post-mortem interval 5 tools
Body-cooling models used to illustrate how a post-mortem interval estimate is constructed. These are teaching implementations of published methods, not casework instruments.
Forensic entomology 6 tools
Thermal accumulation tools. Every one requires species-specific developmental data from an appropriate published source — the calculator supplies the arithmetic, never the reference values.
Bloodstain pattern analysis 4 tools
Stain geometry calculations. Each uses the idealised model taught in training: a spherical droplet, an elliptical stain and no allowance for surface texture or air resistance.
Forensic anthropology 4 tools
Skeletal measurement and inventory tools. Stature estimation depends entirely on choosing a regression equation appropriate to the population and the bone measured.
Laboratory and toxicology calculations 5 tools
General-purpose laboratory arithmetic: elimination kinetics, half-lives, unit conversion and elapsed time between two points.
How to read a forensic estimate
Every calculation in this section produces a number. None of them produces a conclusion. The difference matters more here than anywhere else on the site, so it is worth stating plainly.
What the arithmetic gives you
- A transparent, repeatable result from the values you entered — useful for checking coursework, testing an assumption or seeing how sensitive an answer is to one input.
- A sense of scale. Doubling a lane width halves the search distance; a ten-degree change in ambient temperature transforms an entomological timeline.
What it cannot give you
- A confidence interval. Real estimates are reported as ranges with stated uncertainty; these tools return point values from idealised models.
- Context. Scene disturbance, insulation, water immersion, drug effects, prior refrigeration and dozens of other factors sit outside every model here.
- Validation. None of these implementations has been through the verification, proficiency testing or peer review that casework methods require.
Educational use only. These tools are not validated for medical, legal or investigative casework. Forensic conclusions require scene context, calibrated measurements, appropriate population-specific reference data, documented quality assurance and qualified expert interpretation. Do not enter identifiable case information into any public website.
The published methods behind these calculations are listed on the references page, and the standard each page is written to is set out in my editorial policy.
Common questions
Can these calculators be used in real casework?
No. They are teaching and revision aids built to make published methods visible and checkable. Casework requires validated software, calibrated instruments, documented quality assurance, contemporaneous notes and an expert able to defend the method in court. Nothing on this site meets those requirements, and no result here should appear in a statement or report.
Why do several tools ask me to supply the reference values?
Because the reference value is the science, and it is not interchangeable. A blowfly developmental threshold is species-specific and population-specific; a stature regression is specific to the population, sex and bone it was derived from; a Henssge correction factor depends on body mass, clothing and the surrounding conditions. Supplying a default would invite the most serious error a forensic calculation can make. The tools do the arithmetic and require you to bring the appropriate published figure.
How accurate is a temperature-based time of death estimate?
Far less accurate than fiction suggests. Single-exponential cooling models assume a constant ambient temperature, a known starting temperature and undisturbed conditions — none of which usually hold. Real estimates carry wide confidence intervals that widen further as the interval lengthens, and they are normally corroborated by other evidence such as rigor, livor, gastric contents and entomology rather than relied on alone.
Is the data I enter stored or transmitted?
No. Every tool in this section runs entirely in your browser. Measurements, timestamps, exhibit references and any other value you type are never sent to a server and are not retained as calculator records. Even so, treat the browser as an unsecured environment and do not enter identifiable case information into a public website.
Who is this section written for?
Students on forensic science, criminology and related courses; teachers preparing worked examples; writers who want their procedural detail to be plausible; and anyone curious about how these estimates are actually constructed. It is not written as a professional reference.
Why is the maths so simple compared with published research?
Deliberately. Each tool implements the clearest published form of a method so the relationship between inputs and output stays visible. Research implementations add corrections, error terms and validation steps that would obscure the underlying principle. If you need that level of rigour, work from the primary literature listed on my references page.
Related subjects
Questions rarely sit inside a single subject. These sections cover the calculations most often needed alongside forensic calculations.