Changelog

What changed in September 2026

536 calculators recorded a change this month, shown 100 at a time. The full history for any one of them is on its own page, under "What's changed".

Mortgage Calculator

Last reviewed 22 September 2026

Made the calculator US-only: the region selector and currency switch are gone, and the UK, Canadian, Indian and Australian versions are now their own calculators with each country’s own rules.

5updates in all, on the calculator's own page

UK Mortgage Calculator

Last reviewed 22 September 2026

Added an automated formula suite checked against HMRC’s published bands and hand-computed payments.

3updates in all, on the calculator's own page

Canadian Mortgage Calculator

Last reviewed 22 September 2026

Added an automated formula suite checked against the CMHC premium table and closed-form payments.

3updates in all, on the calculator's own page

Home Loan EMI Calculator

Last reviewed 22 September 2026

Added an automated formula suite checked against bank-published EMI figures and closed-form balances.

3updates in all, on the calculator's own page

Australian Mortgage Calculator

Last reviewed 22 September 2026

Added an automated formula suite with hand-computed repayments and offset and interest-only identities.

3updates in all, on the calculator's own page

Inflation Calculator

Last reviewed 22 September 2026

Added an automated formula suite against BLS published values.

3updates in all, on the calculator's own page

Social Security COLA Calculator

Last reviewed 22 September 2026

Added an automated formula suite with SSA's published COLAs as the outside authority.

3updates in all, on the calculator's own page

Fed Rate Impact Calculator

Last reviewed 22 September 2026

Added an automated formula suite.

2updates in all, on the calculator's own page

Education ROI Calculator

Last reviewed 22 September 2026

Added an automated formula suite with the BLS table as the outside authority.

2updates in all, on the calculator's own page

Random Number Generator

Last reviewed 22 September 2026

Added an automated formula suite including a chi-square uniformity test.

3updates in all, on the calculator's own page

Time Calculator

Last reviewed 22 September 2026

Added an automated formula suite with calendar, golden, boundary and round-trip cases.

3updates in all, on the calculator's own page

Dice Roller

Last reviewed 22 September 2026

Added an automated formula suite checked against the published 2d6 and 3d6 tables.

3updates in all, on the calculator's own page

Password Generator

Last reviewed 22 September 2026

Added an automated formula suite; guidance follows NIST SP 800-63B-4.

3updates in all, on the calculator's own page

GDP Calculator

Last reviewed 22 September 2026

Added the income approach: compensation, rent, interest, profits and proprietors’ income plus indirect taxes and depreciation, with net domestic product and the labor share.

3updates in all, on the calculator's own page

Spending Multiplier Calculator

Last reviewed 22 September 2026

Accepted the MPS as well as the MPC, with the multiplier table built from whichever is known.

3updates in all, on the calculator's own page

Real Interest Rate Calculator

Last reviewed 22 September 2026

Retitled around the real return after inflation, and linked the new Fisher equation calculator.

3updates in all, on the calculator's own page

Personal Inflation Rate Calculator

Last reviewed 22 September 2026

Added an automated formula suite with BLS published figures as the outside authority.

3updates in all, on the calculator's own page

Shrinkflation Calculator

Last reviewed 22 September 2026

Added an automated formula suite with the BLS examples as the outside authority.

3updates in all, on the calculator's own page

Federal Poverty Level Calculator

Last reviewed 22 September 2026

Added an automated formula suite with ASPE's published figures as the outside authority.

3updates in all, on the calculator's own page

National Debt Per Person Calculator

Last reviewed 22 September 2026

Added an automated formula suite.

2updates in all, on the calculator's own page

Average Propensity to Consume Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

3updates in all, on the calculator's own page

Average Propensity to Save Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

2updates in all, on the calculator's own page

Marginal Propensity to Consume Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

2updates in all, on the calculator's own page

Marginal Propensity to Save Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

2updates in all, on the calculator's own page

Consumption Function Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

2updates in all, on the calculator's own page

Savings Function Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

2updates in all, on the calculator's own page

National Savings Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

3updates in all, on the calculator's own page

Private Savings Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

2updates in all, on the calculator's own page

Public Savings Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

3updates in all, on the calculator's own page

Net Capital Outflow Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

2updates in all, on the calculator's own page

Net Exports Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

3updates in all, on the calculator's own page

Real Exchange Rate Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

3updates in all, on the calculator's own page

Marginal Propensity to Import Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

3updates in all, on the calculator's own page

Tax Multiplier Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

2updates in all, on the calculator's own page

Fisher Equation Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

3updates in all, on the calculator's own page

Real GDP Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

3updates in all, on the calculator's own page

Labor Force Calculator

Last reviewed 22 September 2026

Added it to an automated formula suite with golden, independent, property, boundary and structural cases.

3updates in all, on the calculator's own page

Coast FIRE Calculator

Last reviewed 15 September 2026

Explained how to allow for Social Security, a pension or a couple's combined savings.

2updates in all, on the calculator's own page

ROI Calculator

Last reviewed 15 September 2026

Explained that "ROI" on Indian loan documents means the rate of interest, with a link to the Loan Calculator.

6updates in all, on the calculator's own page

Two-Proportion Z-Test Calculator

Last reviewed 15 September 2026

Added how to check the result in Excel (NORM.S.DIST) and on a TI-84 (2-PropZTest), and why its 2-PropZInt interval differs.

6updates in all, on the calculator's own page

Percentage Calculator

Last reviewed 15 September 2026

Added the exam-marks case to the "what percent" question.

5updates in all, on the calculator's own page

Coterminal Angle Calculator

Last reviewed 15 September 2026

Added the 45° case (405° and −315°) to the explanation of coterminal families.

4updates in all, on the calculator's own page

BMI Calculator

Last reviewed 15 September 2026

Pregnancy or breastfeeding now shows the BMI with a notice in place of a category; every category shares one neutral color; the result explains what BMI screens for and adds the National Alliance for Eating Disorders helpline; each source now states what it backs.

3updates in all, on the calculator's own page

TDEE Calculator

Last reviewed 15 September 2026

The weight-loss scenarios now hold the same calorie floors and 2 lb-a-week pace cap; an age under 18 or pregnancy or breastfeeding shows a notice in place of the scenarios; each source now states what it backs.

3updates in all, on the calculator's own page

Calorie Deficit Calculator

Last reviewed 15 September 2026

Every goal method now holds a calorie floor (1,200 female reference, 1,500 male reference) and a 2 lb-a-week pace cap; an age under 18, pregnancy or breastfeeding, or a target below a BMI of 18.5 shows a notice in place of a target; each source now states what it backs.

3updates in all, on the calculator's own page

Time Zone Converter

Last reviewed 15 September 2026

Added a worked example for planning a meeting across time zones.

3updates in all, on the calculator's own page

NPV Calculator

Last reviewed 15 September 2026

Explained how to reproduce the result with Excel’s NPV function without discounting the upfront cost.

3updates in all, on the calculator's own page

Weighted Average Expense Ratio Calculator

Last reviewed 15 September 2026

Added the Excel SUMPRODUCT formula for portfolios with more than four funds.

4updates in all, on the calculator's own page

Cross-Validation Calculator

Last reviewed 13 September 2026

Stated that a tuned error double-counts the tuning and needs a nested procedure.

5updates in all, on the calculator's own page

Partial Least Squares Calculator

Last reviewed 13 September 2026

Stated the overfitting risk that consulting the outcome creates, and when it matters.

5updates in all, on the calculator's own page

Principal Component Regression Calculator

Last reviewed 13 September 2026

Confirmed that using every component reproduces ordinary least squares exactly.

5updates in all, on the calculator's own page

Elastic Net Calculator

Last reviewed 13 September 2026

Confirmed the exact reduction to ridge at a lasso share of zero.

5updates in all, on the calculator's own page

Lasso Regression Calculator

Last reviewed 13 September 2026

Stated why no p-values are offered: selection and estimation used the same data.

5updates in all, on the calculator's own page

Ridge Regression Calculator

Last reviewed 13 September 2026

Shipped a plentiful-data preset where cross-validation correctly declines to shrink.

5updates in all, on the calculator's own page

Tobit Calculator

Last reviewed 13 September 2026

Stated that censoring is not truncation and that a two-part model fits distinct decisions better.

5updates in all, on the calculator's own page

Zero-Inflated Calculator

Last reviewed 13 September 2026

Shipped a preset with no inflation where the model collapses onto the plain Poisson exactly.

5updates in all, on the calculator's own page

Negative Binomial Regression Calculator

Last reviewed 13 September 2026

Compared observed with predicted zeros to separate overdispersion from zero inflation.

5updates in all, on the calculator's own page

Multinomial Logistic Calculator

Last reviewed 13 September 2026

Stated the parameter cost of discarding a genuine ordering.

5updates in all, on the calculator's own page

Ordinal Regression Calculator

Last reviewed 13 September 2026

Noted that sign conventions for ordinal coefficients differ between software packages.

5updates in all, on the calculator's own page

Quantile Regression Calculator

Last reviewed 13 September 2026

Stated that a quantile slope describes the distribution rather than the individuals in it.

5updates in all, on the calculator's own page

Cluster Sample Size Calculator

Last reviewed 13 September 2026

Stated that the equal-size formula understates the requirement when cluster sizes vary.

5updates in all, on the calculator's own page

Design Effect Calculator

Last reviewed 13 September 2026

Stated that this is a planning device rather than a method of analysis.

5updates in all, on the calculator's own page

Mixed Model Calculator

Last reviewed 13 September 2026

Stated that this is method of moments rather than restricted maximum likelihood.

5updates in all, on the calculator's own page

Survival Sample Size Calculator

Last reviewed 13 September 2026

Stated that the formula assumes proportional hazards and what a delayed effect costs.

5updates in all, on the calculator's own page

Competing Risks Calculator

Last reviewed 13 September 2026

Stated that comparing groups needs a different test from the one that matches these curves.

5updates in all, on the calculator's own page

Cox Regression Calculator

Last reviewed 13 September 2026

Stated that a hazard ratio is not a risk ratio and cannot produce a survival probability.

5updates in all, on the calculator's own page

Odds Ratio to Risk Ratio Calculator

Last reviewed 13 September 2026

Stated that the conversion is approximate for an adjusted odds ratio, and why.

5updates in all, on the calculator's own page

Log Loss Calculator

Last reviewed 13 September 2026

Stated the clipping epsilon and how many forecasts hit it.

5updates in all, on the calculator's own page

Brier Score Calculator

Last reviewed 13 September 2026

Stated that Brier scores from different problems are not comparable because of the base rate.

5updates in all, on the calculator's own page

Hosmer-Lemeshow Calculator

Last reviewed 13 September 2026

Stated that the test sees calibration only, which a base-rate forecast passes perfectly.

5updates in all, on the calculator's own page

Poisson Regression Calculator

Last reviewed 13 September 2026

Documented the four causes of overdispersion and which remedy each one calls for.

5updates in all, on the calculator's own page

Logistic Regression Calculator

Last reviewed 13 September 2026

Printed events per parameter, which decides whether any individual coefficient is usable.

5updates in all, on the calculator's own page

VIF Calculator

Last reviewed 13 September 2026

Stated that collinearity damages interpretation rather than prediction.

5updates in all, on the calculator's own page

White Test Calculator

Last reviewed 13 September 2026

Stated that a significant result can mean an omitted non-linear term rather than unequal variance.

5updates in all, on the calculator's own page

Breusch-Pagan Calculator

Last reviewed 13 September 2026

Included a residuals-against-fitted plot beside the statistic.

5updates in all, on the calculator's own page

Influence Diagnostics Calculator

Last reviewed 13 September 2026

Checked every closed form against refits for each row and each coefficient.

5updates in all, on the calculator's own page

Cook's Distance Calculator

Last reviewed 13 September 2026

Computed the distances from a closed form checked against actual leave-one-out refits.

5updates in all, on the calculator's own page

Leverage Calculator

Last reviewed 13 September 2026

Printed the sum of leverages against the parameter count, which trace(H) = p fixes exactly.

5updates in all, on the calculator's own page

Covariance Matrix Calculator

Last reviewed 13 September 2026

Stated that a near-zero entry rules out a straight line rather than a relationship.

5updates in all, on the calculator's own page

Distance Correlation Calculator

Last reviewed 13 September 2026

Made the permutation count a visible control rather than a hidden default.

5updates in all, on the calculator's own page

Multiple Correlation Calculator

Last reviewed 13 September 2026

Printed the sum of unique contributions against R-squared to show how much variance is shared.

5updates in all, on the calculator's own page

Partial Correlation Calculator

Last reviewed 13 September 2026

Documented mediators and colliders as controls that make the adjusted number worse than the raw one.

5updates in all, on the calculator's own page

Hotelling T-Squared Calculator

Last reviewed 13 September 2026

Stated that a significant result does not identify which variable differs.

5updates in all, on the calculator's own page

Mahalanobis Distance Calculator

Last reviewed 13 September 2026

Printed the sum of distances against p(n-1), which must match exactly for any data.

5updates in all, on the calculator's own page

Gauge R&R Calculator

Last reviewed 13 September 2026

Rejected ragged, single-operator and single-trial designs outright rather than returning a plausible-looking number.

5updates in all, on the calculator's own page

Theil-Sen Calculator

Last reviewed 13 September 2026

Checked the estimator against its Kendall-tau characterisation using the site own rank engine rather than against itself.

5updates in all, on the calculator's own page

Concordance Correlation Calculator

Last reviewed 13 September 2026

Corrected two exponents in Lin asymptotic variance before shipping and validated the result against a 4,000-draw simulation at three sample sizes.

5updates in all, on the calculator's own page

Passing-Bablok Calculator

Last reviewed 13 September 2026

Asserted exact recovery of slope and intercept on a noiseless line, as exact equalities rather than tolerances.

5updates in all, on the calculator's own page

Deming Regression Calculator

Last reviewed 13 September 2026

Added a table of the fitted slope across five lambda values, so the sensitivity to the assumption is visible.

5updates in all, on the calculator's own page

Bland-Altman Calculator

Last reviewed 13 September 2026

Listed every subject with its average and difference, and flagged which points fall outside the limits.

5updates in all, on the calculator's own page

Cliff's Delta Calculator

Last reviewed 13 September 2026

Documented where the Romano magnitude bands come from and why they inherit the objections to Cohen conventions.

5updates in all, on the calculator's own page

Hedges' g Calculator

Last reviewed 13 September 2026

Delegated Cohen d to the shared routine used by the effect size calculator and asserted agreement to 1e-14 on 200 designs.

5updates in all, on the calculator's own page

Fleiss' Kappa Calculator

Last reviewed 13 September 2026

Shipped a preset where observed agreement is 0.333333 and expected agreement is identical, so kappa is exactly zero.

5updates in all, on the calculator's own page

Egger's Test Calculator

Last reviewed 13 September 2026

Documented the five causes of funnel asymmetry, only one of which is publication bias.

5updates in all, on the calculator's own page

I² Calculator

Last reviewed 13 September 2026

Made the truncation at zero explicit, including a preset where the raw ratio is -1258.95% and is reported as 0%.

5updates in all, on the calculator's own page

Meta-Analysis Calculator

Last reviewed 13 September 2026

Added log-scale entry for odds, risk and hazard ratios, with the shipped preset pooling to exactly 0.6500.

5updates in all, on the calculator's own page

Mutual Information Calculator

Last reviewed 13 September 2026

Verified that mutual information equals H(X) + H(Y) − H(X,Y) across 150 generated datasets, that it is exactly symmetric in its arguments, and that it never exceeds the smaller of the two entropies.

5updates in all, on the calculator's own page

Cosine Similarity Calculator

Last reviewed 13 September 2026

Explained why Pearson is rarely used on high-dimensional sparse data even where it would be more appropriate — centring turns every zero into a non-zero, so a twelve-multiplication dot product becomes a hundred-thousand-multiplication one.

5updates in all, on the calculator's own page

Jaccard Index Calculator

Last reviewed 13 September 2026

Recorded that all three ignore joint absence, with the practical test for whether that matters: would you be surprised if both sets lacked an item?

5updates in all, on the calculator's own page

Herfindahl Index Calculator

Last reviewed 13 September 2026

Contrasted it with the Gini on the same page: a thousand identical firms have a Gini of 0 and an HHI of 10; two identical firms have a Gini of 0 and an HHI of 5,000. The Gini ignores how many players there are and the HHI does not, which is the whole difference for a competition question.

5updates in all, on the calculator's own page