diff --git a/docs/options.md b/docs/options.md
index d896c77..30de07f 100644
--- a/docs/options.md
+++ b/docs/options.md
@@ -14,6 +14,7 @@ The preset dropdown allows you to choose from a hardcoded list of preloaded STV
 * [*Wright STV*](https://www.aph.gov.au/Parliamentary_Business/Committees/House_of_Representatives_Committees?url=em/elect07/subs/sub051.1.pdf): Rules proposed by Anthony van der Craats designed for computer counting, involving reset and re-iteration of the count after each candidate exclusion. Validated against the [EVE Online reference implementation](https://github.com/ccpgames/ccp-wright-stv) for the [CSM 15 election](https://www.eveonline.com/news/view/meet-the-new-council).
 * [*PRSA 1977*](https://www.prsa.org.au/rule1977.htm): Simple rules designed for hand counting, using the exclusive Gregory method, with counting automatically performed in thousandths of a vote. Validated against [example 1](https://www.prsa.org.au/example1.pdf) of the PRSA's [*Proportional Representation Manual*](https://www.prsa.org.au/publicat.htm#p2).
 * [*ERS97*](https://www.electoral-reform.org.uk/latest-news-and-research/publications/how-to-conduct-an-election-by-the-single-transferable-vote-3rd-edition/): More complex rules designed for hand counting, using the exclusive Gregory method. Validated against the ERS97 model election.
+	* *ERS73*: Former rules from the 1973 1st edition. The quota is calculated always to 2 decimal places – for full ERS73 compliance, set *Round quota to 0 d.p.* when the quota is 100 or more.
 
 This functionality is not available on the command line.
 
diff --git a/html/index.html b/html/index.html
index 8b484e3..5eb1c29 100644
--- a/html/index.html
+++ b/html/index.html
@@ -44,6 +44,7 @@
 						<option value="wright">Wright STV</option>
 						<option value="prsa77">PRSA 1977</option>
 						<option value="ers97">ERS97</option>
+						<option value="ers73">ERS73</option>
 					</select>
 				</label>
 				<button id="btnAdvancedOptions" onclick="clickAdvancedOptions()">Show advanced options</button>
diff --git a/html/index.js b/html/index.js
index d36c505..e5e2209 100644
--- a/html/index.js
+++ b/html/index.js
@@ -548,5 +548,30 @@ function changePreset() {
 		document.getElementById('selPapers').value = 'transferable';
 		document.getElementById('selExclusion').value = 'by_value';
 		document.getElementById('selTies').value = 'forwards,random';
+	} else if (document.getElementById('selPreset').value === 'ers73') {
+		document.getElementById('selQuotaCriterion').value = 'geq';
+		document.getElementById('selQuota').value = 'droop_exact';
+		document.getElementById('selQuotaMode').value = 'static';
+		document.getElementById('chkBulkElection').checked = true;
+		document.getElementById('chkBulkExclusion').checked = true;
+		document.getElementById('chkDeferSurpluses').checked = true;
+		document.getElementById('selNumbers').value = 'fixed';
+		document.getElementById('txtDP').value = '5';
+		document.getElementById('txtPPDP').value = '2';
+		document.getElementById('chkNormaliseBallots').checked = false;
+		document.getElementById('chkRoundQuota').checked = true;
+		document.getElementById('txtRoundQuota').value = '2';
+		document.getElementById('chkRoundVotes').checked = true;
+		document.getElementById('txtRoundVotes').value = '2';
+		document.getElementById('chkRoundTVs').checked = true;
+		document.getElementById('txtRoundTVs').value = '2';
+		document.getElementById('chkRoundWeights').checked = true;
+		document.getElementById('txtRoundWeights').value = '2';
+		document.getElementById('selSumTransfers').value = 'single_step';
+		document.getElementById('selSurplus').value = 'by_size';
+		document.getElementById('selTransfers').value = 'eg';
+		document.getElementById('selPapers').value = 'transferable';
+		document.getElementById('selExclusion').value = 'by_value';
+		document.getElementById('selTies').value = 'forwards,random';
 	}
 }