diff --git a/app/src/App.js b/app/src/App.js
index 12cbc493..343d0de5 100644
--- a/app/src/App.js
+++ b/app/src/App.js
@@ -22,6 +22,7 @@ import {FilePreviewProvider} from "./components/FilePreview";
 import {TagsProvider} from "./Tags";
 import {ZimRoute} from "./components/Zim";
 import {IframeViewer} from "./components/Common";
+import {CalculatorsRoute} from "./components/Calculators";
 
 function PageNotFound() {
     const {t} = useContext(ThemeContext);
diff --git a/app/src/components/Apps.js b/app/src/components/Apps.js
index 289b591f..3791d9f6 100644
--- a/app/src/components/Apps.js
+++ b/app/src/components/Apps.js
@@ -1,5 +1,14 @@
 import React, {useContext} from 'react';
-import {Divider, Input, SegmentGroup, StatisticLabel, StatisticValue, TableCell, TableRow} from "semantic-ui-react";
+import {
+    Divider,
+    Input,
+    Label,
+    SegmentGroup,
+    StatisticLabel,
+    StatisticValue,
+    TableCell,
+    TableRow
+} from "semantic-ui-react";
 import {Link, Route, Routes} from "react-router-dom";
 import {decryptOTP, encryptOTP} from "../api";
 import {
@@ -15,6 +24,7 @@ import {
 import {ThemeContext} from "../contexts/contexts";
 import {Button, Header, Loader, Segment, Statistic, StatisticGroup, Table, TextArea} from "./Theme";
 import {useStatistics, useVINDecoder} from "../hooks/customHooks";
+import {CalculatorsPage} from "./Calculators";
 
 class Encrypt extends React.Component {
     constructor(props) {
@@ -332,9 +342,15 @@ function StatisticsPage() {
 export function MoreRoute(props) {
     return <PageContainer>
         <Routes>
+            <Route path='calculators' element={<CalculatorsPage/>}/>
             <Route path='otp' exact element={<OTP/>}/>
             <Route path='statistics' exact element={<StatisticsPage/>}/>
             <Route path='vin' exact element={<VINDecoder/>}/>
         </Routes>
     </PageContainer>
 }
+
+export function ColoredInput({name, value, label, color, ...props}) {
+    label = label ? <Label color={color}>{label}</Label> : null;
+    return <Input value={value} name={name} label={label} {...props}/>
+}
\ No newline at end of file
diff --git a/app/src/components/Calculators.js b/app/src/components/Calculators.js
new file mode 100644
index 00000000..1e71a60f
--- /dev/null
+++ b/app/src/components/Calculators.js
@@ -0,0 +1,262 @@
+import React from "react";
+import {BackButton, roundDigits, useTitle} from "./Common";
+import {Button, Header, Icon} from "./Theme";
+import {GridColumn, GridRow, Input} from "semantic-ui-react";
+import Grid from "semantic-ui-react/dist/commonjs/collections/Grid";
+import {useCalcQuery} from "../hooks/customHooks";
+import {ColoredInput} from "./Apps";
+
+function TemperatureCalculator() {
+    const [state, setState] = React.useState({
+        celsius: '',
+        fahrenheit: '',
+        kelvin: '',
+    })
+
+    const handleInputChange = (e, {name, value}) => {
+        if (value === '') {
+            // User has cleared the input;
+            setState({volt: '', ohm: '', amp: ''});
+            return
+        }
+
+        const numValue = parseFloat(value.endsWith('.') ? `${value}0` : value);
+        console.debug(`Calculating ${value} ${name}`);
+        let newCelsius;
+        let newKelvin;
+        let newFahrenheit;
+        if (name === 'fahrenheit') {
+            newFahrenheit = value;
+            newCelsius = roundDigits((numValue - 32) / 1.8);
+            newKelvin = roundDigits(newCelsius + 273.15);
+        } else if (name === 'celsius') {
+            newCelsius = value;
+            newFahrenheit = roundDigits((numValue * 1.8) + 32);
+            newKelvin = roundDigits(numValue + 273.15);
+        } else if (name === 'kelvin') {
+            newKelvin = value;
+            newCelsius = roundDigits(numValue - 273.15);
+            newFahrenheit = roundDigits((newCelsius * 1.8) + 32);
+        }
+        setState({
+            celsius: newCelsius,
+            fahrenheit: newFahrenheit,
+            kelvin: newKelvin
+        });
+    }
+
+    const handleClick = (e) => {
+        e.target.select();
+    }
+
+    const commonInputProps = {
+        fluid: true,
+        labelPosition: 'right',
+        type: 'number',
+        onChange: handleInputChange,
+        onClick: handleClick
+    };
+
+    return <Grid columns={3}>
+        <GridRow>
+            <GridColumn>
+                <Input value={state.celsius} label='°C' name='celsius' {...commonInputProps}/>
+            </GridColumn>
+            <GridColumn>
+                <Input value={state.fahrenheit} label='°F' name='fahrenheit' {...commonInputProps}/>
+            </GridColumn>
+            <GridColumn>
+                <Input value={state.kelvin} label='K' name='kelvin' {...commonInputProps}/>
+            </GridColumn>
+        </GridRow>
+    </Grid>
+}
+
+const initialState = {
+    volts: '',
+    amps: '',
+    ohms: '',
+    watts: '',
+    lastUpdated: [],
+};
+
+// Ohms Law functions.  These take two values, and return the other two electrical values.
+const voltsAmps = (volts, amps) => {
+    const watts = volts * amps;
+    const ohms = volts / amps;
+    return [roundDigits(watts) || 0, roundDigits(ohms) || 0]
+};
+const voltsOhms = (volts, ohms) => {
+    const amps = volts / ohms;
+    const watts = volts * amps;
+    return [roundDigits(amps) || 0, roundDigits(watts) || 0]
+};
+const ampsOhms = (amps, ohms) => {
+    const volts = amps * ohms;
+    const watts = volts * amps;
+    return [roundDigits(volts) || 0, roundDigits(watts) || 0]
+};
+const voltsWatts = (volts, watts) => {
+    const amps = watts / volts;
+    const ohms = volts / amps;
+    return [roundDigits(amps) || 0, roundDigits(ohms) || 0]
+};
+const ampsWatts = (amps, watts) => {
+    const volts = watts / amps;
+    const ohms = volts / amps;
+    return [roundDigits(volts) || 0, roundDigits(ohms) || 0]
+};
+const wattsOhms = (watts, ohms) => {
+    const volts = Math.sqrt(watts * ohms);
+    const amps = volts / ohms;
+    return [roundDigits(volts), roundDigits(amps)]
+};
+
+function ohmsLawReducer(state, action) {
+    const {type, value} = action;
+    let {volts, amps, ohms, watts, lastUpdated} = state;
+
+    // Only replace last updated when a different input was updated.
+    let newLastUpdated = lastUpdated;
+    if (lastUpdated.length === 0) {
+        newLastUpdated = [type];
+    } else if (lastUpdated.length === 1 && lastUpdated[0] !== type) {
+        newLastUpdated = [...lastUpdated, type];
+    } else if (lastUpdated.length > 1 && lastUpdated[1] !== type) {
+        newLastUpdated = [lastUpdated[1], type];
+    }
+
+    // Copy new value into it's respective state.  Do not allow negative numbers.
+    if (type === 'amps') {
+        amps = Math.abs(value);
+    } else if (type === 'volts') {
+        volts = Math.abs(value);
+    } else if (type === 'ohms') {
+        ohms = Math.abs(value);
+    } else if (type === 'watts') {
+        watts = Math.abs(value);
+    }
+
+    // Sort the updated values, so we don't have to define everything twice.
+    const sortedLastUpdated = [...newLastUpdated].sort().join(',');
+    switch (sortedLastUpdated) {
+        case 'amps,ohms':
+            [volts, watts] = ampsOhms(amps, ohms);
+            break;
+        case 'amps,volts':
+            [watts, ohms] = voltsAmps(volts, amps);
+            break;
+        case 'amps,watts':
+            [volts, ohms] = ampsWatts(amps, watts);
+            break;
+        case 'ohms,volts':
+            [amps, watts] = voltsOhms(volts, ohms);
+            break;
+        case 'ohms,watts':
+            [volts, amps] = wattsOhms(watts, ohms);
+            break;
+        case 'volts,watts':
+            [amps, ohms] = voltsWatts(volts, watts);
+            break;
+    }
+
+    return {volts, amps, ohms, watts, lastUpdated: newLastUpdated};
+}
+
+function ElectricalCalculator() {
+    // Provides a form which provides 4 inputs (volts, amps, ohms, watts), and calculates the missing values.
+
+    const [state, dispatch] = React.useReducer(ohmsLawReducer, initialState);
+
+    const calculateColor = (name) => {
+        // Recently updated inputs are white, others are grey.
+        return state.lastUpdated.indexOf(name) >= 0 ? null : 'grey';
+    }
+
+    const inputProps = {
+        fluid: true,
+        type: 'number',
+        labelPosition: 'right',
+        onSelect: e => e.target.select(), // Select the contents of the Input when a user selects it.
+    };
+
+    return <div>
+        <Header as='h4'>Ohm's Law</Header>
+        <Grid columns={2}>
+            <GridRow>
+                <GridColumn>
+                    <ColoredInput {...inputProps}
+                                  value={state.volts}
+                                  onChange={e => dispatch({type: 'volts', value: e.target.value})}
+                                  label='Volts'
+                                  color={calculateColor('volts')}
+                    />
+                </GridColumn>
+                <GridColumn>
+                    <ColoredInput {...inputProps}
+                                  value={state.amps}
+                                  onChange={e => dispatch({type: 'amps', value: e.target.value})}
+                                  label='Amps'
+                                  color={calculateColor('amps')}
+                    />
+                </GridColumn>
+            </GridRow>
+            <GridRow>
+                <GridColumn>
+                    <ColoredInput {...inputProps}
+                                  value={state.ohms}
+                                  onChange={e => dispatch({type: 'ohms', value: e.target.value})}
+                                  label='Ohms'
+                                  color={calculateColor('ohms')}
+                    />
+                </GridColumn>
+                <GridColumn>
+                    <ColoredInput {...inputProps}
+                                  value={state.watts}
+                                  onChange={e => dispatch({type: 'watts', value: e.target.value})}
+                                  label='Watts'
+                                  color={calculateColor('watts')}
+                    />
+                </GridColumn>
+            </GridRow>
+        </Grid>
+    </div>
+}
+
+export function CalculatorsPage() {
+    const {calc, setCalc} = useCalcQuery();
+
+    const calculators = [
+        {key: 'temperature', icon: 'thermometer', button: 'Temperature', contents: <TemperatureCalculator/>},
+        {key: 'electrical', icon: 'lightning', button: 'Electrical', contents: <ElectricalCalculator/>},
+    ];
+
+    const activeCalculator = calc ?
+        calculators.filter(i => i.key === calc)[0]
+        : null;
+    const {button, title, contents} = activeCalculator || {};
+
+    const name = title || button + ' Calculator';
+    const header = activeCalculator ? name : 'Calculators';
+    useTitle(header);
+
+    const calculatorButtons = calculators.map(i => {
+        const {button, icon, key} = i;
+        return <Button key={key} onClick={() => setCalc(i.key)}>
+            {icon && <Icon name={i.icon}/>}
+            {button}
+        </Button>
+    });
+
+    const body = activeCalculator ? <>
+            <BackButton style={{marginBottom: '1em'}}/>
+            <span>{contents}</span>
+        </>
+        : calculatorButtons;
+
+    // TODO add Breadcrumb here.
+    return <>
+        <Header>{header}</Header>
+        {body}
+    </>
+}
diff --git a/app/src/components/Common.js b/app/src/components/Common.js
index 320fb1e0..ba515c06 100644
--- a/app/src/components/Common.js
+++ b/app/src/components/Common.js
@@ -1255,9 +1255,9 @@ export function DirectoryInput({disabled, error, placeholder, setInput, value, r
     </div>;
 }
 
-export const BackButton = () => {
+export const BackButton = ({...props}) => {
     const navigate = useNavigate();
-    return <Button icon='arrow left' content='Back' onClick={() => navigate(-1)}/>;
+    return <Button icon='arrow left' content='Back' onClick={() => navigate(-1)} {...props}/>;
 }
 
 export const ColorToSemanticHexColor = (color) => {
@@ -1715,4 +1715,8 @@ export function IframeViewer({title, viewerUrl}) {
                 }}/>
         </Media>
     </>
-}
\ No newline at end of file
+}
+
+export function roundDigits(value, decimals = 2) {
+    return Number(Math.round(value + 'e' + decimals) + 'e-' + decimals);
+}
diff --git a/app/src/components/Nav.js b/app/src/components/Nav.js
index 77288a34..03faa3a7 100644
--- a/app/src/components/Nav.js
+++ b/app/src/components/Nav.js
@@ -20,6 +20,7 @@ const links = [
             {text: 'Inventory', to: '/inventory', key: 'inventory'},
             {to: '/more/otp', text: 'One Time Pad', end: true},
             {to: '/more/vin', text: 'VIN Decoder', end: true},
+            {to: '/more/calculators', text: 'Calculators', end: true},
             {to: '/more/statistics', text: 'Statistics', end: true},
         ]
     },
diff --git a/app/src/hooks/customHooks.js b/app/src/hooks/customHooks.js
index 5a4880d3..7e47eddb 100644
--- a/app/src/hooks/customHooks.js
+++ b/app/src/hooks/customHooks.js
@@ -1186,3 +1186,8 @@ export const useDockerized = () => {
     const {status} = React.useContext(StatusContext);
     return status && status['dockerized'] === true;
 }
+
+export const useCalcQuery = () => {
+    const [calc, setCalc] = useOneQuery('calc');
+    return {calc, setCalc}
+}
\ No newline at end of file